Electrical Wiring Residential Canadian 7th Edition Mullin Solutions Manual [7 ed.]

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Instructor’s Solutions Manual to accompany

Prepared by Sandy F. Gerolimon Humber College

Instructor’s Solutions Manual to accompany Electrical Wiring: Residential, Seventh Canadian Edition By Mullin, Branch, Gerolimon, Trineer, Todd, Simmons Instructor Solutions Manual prepared by Sandy Gerolimon, Humber College Available on the SSO Instructor’s site at http://www.nelson.com/instructor COPYRIGHT © 2016 by Nelson Education Ltd. Nelson is a registered trademark used herein under licence. All rights reserved. For more information contact Nelson, 1120 Birchmount Road, Toronto, Ontario M1K 5G4. Or you can visit our Internet site at www.nelson.com ALL RIGHTS RESERVED. No part of this work covered by the copyright hereon may be reproduced or used in any form or by any means—graphic, electronic, or mechanical, including photocopying, recording, taping, web distribution or information storage and retrieval systems—without the written permission of the publisher.

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Table of Contents To the Instructor

v

Unit 1

General Information for Electrical Installations

1-1

Unit 2

Drawings and Specifications

2-1

Unit 3

Service Entrance Calculations

3-1

Unit 4

Service Entrance Equipment

4-1

Unit 5

Electrical Outlets

5-1

Unit 6

Determining the Number and Location of Lighting and Receptacle Branch Circuits

6-1

Conductor Sizes and Types, Wiring Methods, Wire Connections, Voltage Drop, Neutral Sizing for Services

7-1

Switch Control of Lighting Circuits, Receptacle Bonding, and Induction Heating Resulting from Unusual Switch Connections

8-1

Ground-Fault Circuit Interrupters, Arc Fault Circuit Interrupters, Transient Voltage Surge Suppressors, and Isolated Ground Receptacles

9-1

Unit 10

Lighting Fixtures and Ballasts

10-1

Unit 11

Branch Circuits for the Bedrooms, Study, and Halls

11-1

Unit 12

Branch Circuits for the Living Room and Front Entry

12-1

Unit 13

Branch Circuits for Bathrooms

13-1

Unit 14

Lighting Branch Circuit and Small Appliance Circuits for the Kitchen

14-1

Unit 15

Special Purpose Outlets for Ranges, Counter-Mounted Cooking Units Wall-Mounted Ovens , Food Waste Disposals , and Dishwashers

, 15-1

Unit 16

Branch Circuits for the Laundry, Washroom, and Attic

16-1

Unit 17

Electric Heating and Air Conditioning

17-1

Unit 7

Unit 8

Unit 9

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Unit 18

Oil and Gas Heating Systems

18-1

Unit 19

Recreation Room

19-1

Unit 20

Branch Circuits for Workshop and Utility Area

20-1

Unit 21

Heat and Smoke Detectors, Carbon Monoxide Detectors, and Security Systems

21-1

Unit 22

Swimming Pools, Spas, and Hot Tubs

22-1

Unit 23

Television, Telephone, Data, and Home Automation Systems

23-1

Unit 24

Lighting Branch Circuit for the Garage and Outdoor Lighting

24-2

Unit 25

Standby Power Systems

25-1

Unit 26

Residential Utility-Interactive Solar Photovoltaic Systems

26-1

Review Examination

R-1

Answers to the Review Examination

A-1

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To the Instructor The Seventh Canadian Edition of Electrical Wiring: Residential provides basic instructions for students, apprentices, and technicians. In order to assist the instructors it has been planned that each text unit can serve as its own lesson plan with review questions at the end of each chapter to summarize the material covered. The text units are sequenced to introduce the student to basic principles with progression to more advanced material. It is hoped that this will simplify the learning process. It is expected that the students will possess a reasonable level of mechanical aptitude skills and will also receive some supplemental instruction in blueprint reading for the building trades. The material emphasizes the 2015 Canadian Electrical Code (CEC), Part I, and all students should be encouraged to study the CEC in conjunction with their comprehensive study of Electrical Wiring: Residential. To assist the instructor, questions from the end of each unit have been included with answers/solutions. These may be used as additional review or examination questions. The diagrams have been checked and corrected from the previous edition to aid in the instructor facilitations of the program. We hope you enjoy this guide with Electrical Wiring: Residential and would appreciate suggestions for any improvements/additions that may be included in subsequent editions. Sandy Gerolimon can be reached at: [email protected].

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 1 General Information for Electrical Installations Solutions to Review Note: Where applicable, responses should be written in complete sentences. 1.

What is the difference between a code and a standard? a. Codes are standards that deal with life safety issues. b. Standards describe minimum performance levels.

2. What Code sets standards for the installation of electrical equipment? The Canadian Electrical Code, Part I, (CEC) is the basic standard, with local and provincial codes as standards that must also be considered. 3. What authority enforces the standards set by the CEC? The provincial or local electricity inspection authority. 4. Does the CEC provide minimum or maximum standards? The CEC standards are minimum standards but are expressed in both minimum and maximum terms. For example, Rule 2-308 is a minimum clearance of 1 m around electrical equipment, while Rule 8-104 is a maximum circuit loading. Both of these are minimum standards. 5. What do the letters CSA signify? Canadian Standards Association 6. Does compliance with the CEC always result in an electrical installation that is adequate, safe, and efficient? Why? Section O of the CEC states that “Compliance with the requirements of this Code and proper maintenance will ensure an essentially safe installation.” But if adequate provision is not made for future expansion, a hazardous condition could develop. 7. What are the general sections of the CEC? According to Table 1-1, the general sections of the CEC are Sections 0 to 16, and 26. 8. Is the section of the CEC that deals with wiring methods a general section or an amending section? General section. 9. When is an electrical installation required to be inspected? ALL work is required to be inspected. 10. What should you look for when trying to determine if a piece of electrical equipment is approved for use in Canada? CSA or other approval mark on the equipment.

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11. If a piece of electrical equipment is not approved for use in Canada, what should you do? Special inspection should be obtained for the equipment. 12. When the words “shall be” appear in a code reference, they mean that it (must) (may) (does not have to) be done. (Underline the correct answer.) must

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 2 Drawings and Specifications Solutions to Review

Note: For these exercises, refer to the blueprints provided with this textbook. Also, refer to the CEC when necessary. Where applicable, responses should be written in complete sentences. PART 1—DRAWING PLANS 1. Identify three line types shown on Sheet 2. Centre lines, border lines, hidden lines, dimension lines, visible lines 2. Determine the length of the lines for the following. SCALE

LENGTH

1:50

3m

1:75

4.5 m

1:100

6m

⅛″ = 1 ft

19 ft, or 5.71 m

¼″ = 1 ft

9 ft 6 in, or 2.9 m

3. What is the purpose of specifications? To supplement the plans by providing written information on materials and to the methods of construction. 4. In what additional way are the specifications particularly useful to the electrical contractor? They allow the contractor to prepare an accurate cost estimate without having to find all the data in the plans. 5. What is done to prevent a plan from becoming confusing because of too much detail? Symbols are used that refer to a table or notes. Information is supplied in the specifications. 6. Name three requirements contained in the specifications regarding material (Appendix A). a. Shall be all new b. Size and types specified c. Carry a label from an approved testing organization. 7. What are the two main hazards that the CEC is designed to prevent? a. Shock b. Fire

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8. What phrase is used when a substitution is permitted for a specific item in a specification? “or equivalent” 9. What is the purpose of an electrical symbol? To represent electrical equipment and components. 10. What is a notation? A note providing additional or more specific information. 11. List five electrical notations found on the plans for the residence used as an example in this textbook. Refer to the blueprints provided with this textbook. Found on the electrical drawing sheets. E6 is as follows:

PROVIDE TR, G.F.C.I. AND A.F.C.I. AS REQUIRED BY THE CANADIAN ELECTRICAL CODE

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Electrical Wiring: Residential, Seventh Canadian Edition

The following is found on the electrical drawing sheets. E5 is as follows:

PART 2—STRUCTURAL FEATURE 1. To what scale is the basement plan drawn? See plans. 1:50 2. What is the size of the footing for the steel support columns in the basement? 610 x 610 x 305 3. To what kind of material will the front porch lighting bracket fixture be attached? The fixture will be supported by fastening it to the electrical outlet box, which is set into the wood siding. 4. Give the size, spacing, and direction of the ceiling joists in the workshop. 50 x 255 @ 305 on centre, running front to rear. 5. What is the size of the lot on which this residence is located? 30 x 46 m 6. In what compass direction is the front of the house facing? 30 x 46 m

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7. How far is the front garage wall from the curb? 10.67 m 8. How far is the side garage wall from the property lot line? 9.145 m = 7620 (garage to set back) + 1525 (setback measurement) (shown on DWG #1 Site plan) 9. How many steel support columns are in the basement, and what size are they? 5 columns @ 76 mm outer diagram (shown on DWG #2 Basement) 10. What is the purpose of the I-beams that rest on top of the steel support columns? To support the floor joists. 11. Is the entire garage area to have a concrete floor? Yes. 12. Where is access to the attic provided? In the garage. 13. Give the thickness of the outer basement walls. 305 mm 14. What material is indicated for the foundation walls? Poured concrete. 15. Where are the smoke detectors located in the basement? One in the workshop near the entrance way; one at the foot of the basement stairs. 16. What is the ceiling height in the basement workshop from bottom of joists to floor? (DWG#4 Section A-A) 2690 - 255 = 2435 mm 17. Give the size and type of the front door. 813 x 2032 x 45 mm decorative with /light Sheet 7 under Door schedule 18. Who is to furnish the range hood? The electrical contractor. Appendix A, number 15. 19. Who is to install the range hood? The electrical contractor. Appendix A, number 19.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 3 Service Entrance Calculations Solutions to Review

Note: Refer to the CEC or to the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. When a service entrance calculation results in a value of 15 kW or more, what is the minimum size service required by the CEC? 100 amperes 2. a. What is the demand load per 90 m2 for the general lighting load of a residence? The first 90 m² has a demand of 5000 watts, and each 90 m² after has a demand of 1000 watts. Rule 8-200(1)(a)(i,ii) b. What are the demand factors for the baseboard heating load in dwellings? The first 10 kW at 100% and the remainder at 75% when automatic thermostatic control is provided in each room or area. Rule 62-118 (3)(a,b). 3. a. What is the ampere rating of the circuits that are provided for the lighting and power loads? The ampere rating is based on the lower value of the wire in the branch circuit or the fuse or circuit breaker protecting the circuit. Rule 8-104(1). In this residence, the rating is 15 amps. b. What is the maximum number of outlets permitted on a 15-ampere branch circuit by the CEC? 12 maximum. Rule 8-304(1). The maximum number of outlets may be exceeded if the load is not greater than 80% of the fuse or breaker. Rule 8-304(3). c. How many 15-ampere circuits are included in this residence? Main Panel A – 14 and Panel B – 14 (Sheet 7 of 8 Panel Schedule) 4. Why is the air-conditioning load for this residence omitted in the service calculations? What is the CEC rule number? Rule 8-106(4). Since a central air conditioning system in installed, it is electrically interlocked with the heating system such that only one of the two loads can operate at a time. 5. What demand factor may be applied to loads greater than 1500 watts, such as a clothes dryer and water heater, in addition to an electric range, Rule 8–200(1)(a)(vi). A demand of 25% is applied to the rating of the appliance. 6. What load may be used for an electric range rated at not over 12 kW? 6 kW. Rule 8-200(1)(a)(iv). 7. What is the load for an electric range rated at 16 kW, Rule 8–200(1)(a)(v)? Show calculations. 1st 12 kW = 6000 W Next 4 kW @ 40% = 1600 W Total = 7600 W

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8. What is the computed load when fixed electric heating is used in a residence? (Rule 62–116) If baseboard heating is used, then any amount over 10 kW may be reduced to 75%. If the heating is central forced air electric, the rating of the furnace applies at 100%. 9. On what basis is the neutral conductor of a service entrance determined? It is sized according to Rule 4-024(3) for the minimum size. This is based on the demand watts of the loads with a neutral (120 v or 120/240 v loads), divided by 240 volts for a 120/240-volt service. Most utilities require the neutral to be the same size as the line conductors except where there is an obvious large 240-volt load, as in the case of electric baseboard heating. 10. Why is it permissible to omit an electric space heater, water heater, and certain other 240-volt equipment when calculating the size of the neutral service entrance conductor for a residence? Because the equipment does not require a neutral or an identified conductor. 11. Calculate the minimum size of service entrance conductors required for a residence containing the following: floor area 8 m × 12 m; 12-kW electric range; 5-kW dryer 120/240-volt; 2200-watt sauna heater, 120-volt; 12 kW of baseboard heaters with individual thermostat control, 240-volts; two 3-kW, 240-volt air conditioners; 3-kW, 240-volt water heater. CALCULATIONS Area 96 m² Heating (12kW – 10kW@100% – 2kW@75%) Range Dry, Water Heater Sauna A/C* Total demand watts

6000 W 11500 W 6000 W 2000 W 2200 W 6000 W 33700 W

I = P/E 33.7 kW/240V = 140.42 amperes (L1, L2) & N * Rule 8-106(4) (not interlocked with heating) (L1, L2) Determine the sizes of the ungrounded conductors and the neutral conductor. Use type RW90 copper conductors. Two # 1/0 RW90 ungrounded conductors One # 1/0 RW90 neutral (or bare neutral if permitted) One # 6 AWG system grounding conductor to water meter (Rule 10-812(a))

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Electrical Wiring: Residential, Seventh Canadian Edition

STUDENT CALCULATIONS (Remember: MINIMUM Requirements) Minimum service ampacity Minimum switch Minimum fuse or circuit breaker Minimum bonding jumper 41 Minimum conduit size Minimum panel ampacity Minimum number of circuits in panel

140.42 amperes (Rule 8-104(1)) 200 amperes 150 amperes Table 13 (supplier you will get 200 amperes) #6 AWG Rule 10-614 (1)(a), Table 41 mm Table 6B 200 amperes 30 – of which ½ DP Rule 8-108(1)(c)

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 4 Service Entrance Equipment Solutions to Review

Note: Refer to the CEC or to the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Where does a consumer’s service start and end? A consumer’s service starts where the service drop conductors from the utility are attached and ends at the terminals in the service box, which is usually the main switch or circuit breaker. 2. What are supply service conductors? Conductors from the utility mains to the consumer service. 3. Who is responsible for determining the service location? The supply authority. Rule 6-408(f). 4. a. [Circle one.] The service head must be located (above) (below) the point where the supply service conductors are spliced to the consumer’s service conductors. b. What CEC rule provides the answer to part (a)? Rule 6-116(b). 5. a. What size and type of conductors are installed for this service? 3/0 AWG RW90 XLPE 600V without jacket. b. What size of conduit is installed? 53 mm, Table 6A. c. What size of grounding electrode conductor (system grounding conductor) is installed? (Not neutral) #6 AWG, Rule 10-812(a). d. Is the grounding electrode conductor insulated, armoured, or bare? Bare. 6. How and where is the grounding electrode conductor attached to the water pipe? The grounding electrode conductor is attached with a ground clamp to the water pipe where it enters the basement wall. 7. When a service mast is extended through a roof, must it be guyed? When the distance between the upper support clamp and the point of attachment is greater than 1.5 m, or if the supply service is greater than 30 m in length, then it should be guyed. Rule 6-112(4), Appendix B.

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8. What are the minimum distances or clearances for the following? a. Supply service conductors, clearance over private driveway 4 m, Rule 6-112(2)(b). b. Supply service conductors, clearance over private sidewalks 3.5 m, Rule 6-112(2)(d). c. Supply service conductors, clearance over alleys 5.5 m, Rule 6-112(2)(a). d. Supply service conductors, clearance over a roof having a roof pitch that may be walked on. (Voltage between conductors does not exceed 300 volts.) 2.5 m, Rule 12310. e. Supply service conductors, horizontal clearance from a porch 1 m, Rule 6-112(3). f. Supply service conductors, clearance from a window or door 1 m, Rule 6-112(3). 9. What size of ungrounded conductors is installed for each of the following residential services? (Use type RW90 XLPE copper conductors). a. 60-ampere service #6 RW90 XLPE copper. Use 75ᴼColumn. b. 100-ampere service #3 RW90 XLPE copper. Use 75ᴼColumn. c. 200-ampere service #3/0 RW90 XLPE copper. Use 75ᴼColumn. 10. What size of grounding electrode conductors are installed for the services listed in Question 9? (Rule 10–812) a. 60-ampere service #6 AWG grounding conductor (Rule 10–812(a)). b. 100-ampere service #6 AWG grounding conductor (Rule 10–812(a)). c. 200-ampere service #6 AWG grounding conductor (Rule 10–812(a)). 11. What is the recommended height of a meter socket from the ground? The local utility must always be contacted for the exact height measurement. Usually the height is 1.73 m measured to the centre of the meter socket above finished grade. The rule of thumb is eye level, but that depends on how tall you are and if the ground you are standing on is finished grade. 12. a. What is the minimum length of conductor that must be left extending out of the service head? 750 mm b. What CEC rule covers this? Rule 6-302. 13. What are the restrictions on the use of bare neutral conductors? a. Copper and run in raceway. b. Aluminum in aluminum or non-metallic raceway above ground. c. Part of busway or service entrance cable. d. Part of neutral supported cable used in accordance with Rule 6-302(2). 14. How far must mechanical protection be provided when underground service conductors are carried up a pole? Rigid conduit is to be used to provide mechanical protection where the wire is exposed to injury. This protection is to be within 600 mm (24”) of the utility connection point. Check with your local supply authority.

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Electrical Wiring: Residential, Seventh Canadian Edition

15. What is the maximum number of consumer’s services allowed without special permission? Four. Quote the CEC rule. Rule 6-104. 16. Complete the following table by filling in the columns with the appropriate information. [Note to formatter: answers are in red; those cells of the table should be blank for studentfacing question] CIRCUIT NUMBER B 16

AMPERE RATING 15

A 19

15

1

120

14

A 5, 7

20

2

240

12

D. ATTIC EXHAUST FAN E. KITCHEN LIGHTING F. HYDROMASSAGE TUB G. ATTIC LIGHTING

A 10

15

1

120

14

B7

15

1

120

14

A9

15

1

120

14

B 20

15

1

120

14

H. COUNTERMOUNTED COOKING UNIT I. ELECTRIC FURNACE

B 2, 4

40

2

240

8

A 1, 3

70

2

240

4

A. LIVING ROOM RECEPTACLE OUTLETS B. WORKBENCH RECEPTACLE OUTLETS C. WATER PUMP

POLES VOLTS WIRE SIZE 1 120 14

17. a. What size of conductors supply Panel B? #3 RW90 XLPE 600 V unjacketed. b. What size of conduit? 27 mm, Table 6A. c. Is this raceway run in the form of EMT or rigid conduit? EMT. d. What size of overcurrent device protects the feeders to Panel B? 100A double pole. 18. How many electric meters are provided for this residence? One. 19. According to the CEC, is it permissible to ground rural service entrance systems and equipment to driven ground rods when a metallic water system is not available? Yes. Rule 10-700. 20. What CEC table lists the sizes of grounding electrode conductors to be used for service entrances of various sizes similar to the type found in the residence discussed in this text? Rule 10-812(a), #6 AWG copper.

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21. Do the following conductors require mechanical protection? a. # 8 grounding conductor Yes. Rule 10-806(3). b. # 6 grounding conductor No, unless rigidly stapled to the construction. Rule 10-806(2). c. # 4 grounding conductor No, unless rigidly stapled to the construction. Rule 10-806(2). 22. Why is bonding service entrance equipment necessary? Since the service-entrance conductors are not fused, a fault on one or more of the service conductors may result in high current attempting to flow to ground. Proper bonding provides a low-impedance path to ground, rather than passing the heavy flow of current through possibly loose locknuts, bushings, or eccentric and concentric knockouts, resulting in severe arcing and sparking. 23. What special types of bushings are required on service entrances when metallic raceways are used? Bonding or grounding bushings. 24. When #8 AWG conductors or larger are installed, what additional provision is required on the conduit ends? Insulation must be provided. Use insulating bushings with double locknuts, combination insulating and metal bushings, insulating sleeves (insuliner), or any other approved insulating means. Rule 12-906(2). 25. What minimum size copper bonding jumpers must be installed to properly bond the electric service for the residence discussed in this text? 200A Service #6 copper. Table 41 for size of bonding jumper. 26. a. What is a Type D fuse? A plug fuse that has time-delay characteristics. b. Where could a Type D fuse be installed? In circuits containing motor loads or cycling loads such as electric water heaters. 27. a. What is the maximum voltage permitted between conductors when using plug fuses? Not over 125 volts between conductors unless the circuit has a grounded neutral and operates at not more than 150 volts to ground. b. May plug fuses be installed in a switch that disconnects a 120/240-volt clothes dryer? Plug fuses shall not be used in circuits exceeding 125 volts between conductors except if the system has a grounded neutral where no conductor is more than 150 volts to ground. So, in this case, yes, you can.

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Electrical Wiring: Residential, Seventh Canadian Edition

c. Give a reason for the answer to (b). Since it’s a three-wire system that has the neutral in the system, the conductor voltage to ground between any conductor to ground does not exceed 150 volts, so you can. Rule 14-202 supports this answer. 28. What part of a circuit breaker causes the breaker to trip a. on an overload? Bimetallic element. b. on a short circuit? Magnetic coil. 29. List the standard sizes of circuit breakers up to and including 100 amperes. 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, and 100 amperes. 30. Using the method shown in this unit, what is the approximate short-circuit current available at the terminals of a 50-kVA single-phase transformer rated 120/240 volts? The transformer impedance is 1%. a. Line-to-line? I = 50 x 1000/240 = 208.33 amperes Multiplier equals 100/1 = 100 208.33 x 100 = 20833 amperes available, short-circuit current, line-to-line. b. Line-to-neutral? 20833 x 1.5 = 31250 amperes available, short-circuit current, line-to-neutral. 31. Where is the service for this residence located? On the east wall. 32. a. On what type of wall is Panel A fastened? Cement block. b. On what type of wall is Panel B fastened? Cement block. 33. When conduits pass through the wall from outside to inside, the conduit must be sealed to prevent air circulation through the conduit. 34. Briefly explain why electrical systems and equipment are grounded. Electrical systems are grounded to minimize the line surges and stabilize the normal voltage to ground. Equipment is grounded to minimize the voltage to ground on that equipment. 35. What CEC rule states that all overcurrent devices must have adequate interrupting ratings for the current to be interrupted? Rule 14-012. 36. All electrical components have some sort of “withstand rating,” which indicates the ability of the component to withstand fault currents for the time required by the overcurrent device to open the circuit. What CEC rule refers to withstand ratings with reference to fault current protection? Rule 14-012(a), Appendix B.

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37. Arcing fault damage is closely related to the value of ampere-squared-seconds (I ² T). 38. In general, systems are grounded so that the maximum voltage to ground does not exceed [circle one] a. 120 volts. b. 150 volts. c. 300 volts. 39. An electric clothes dryer is rated at 5700 watts. The electric rate is 10.091 cents per kWh. The dryer is used continuously for three hours. Find the cost of operation, assuming that the heating element is on continuously. Cost = 5700 x 3 x 0.10091/1000 = 1.726 ($1.73) 40. Rule 14–012 requires that the service equipment (breakers, fuses, and the panel itself) be rated [circle one] a. equal to or greater than the current it must interrupt. b. equal to or greater than the available voltage and the fault current that is available at the terminals. 41. Read the meter below. Last month’s reading was 22 796. How many kilowatt-hours of electricity were used for the current month?

The meter shows the following dial setting: 23 079. 23 079 – 22 796. This leaves a difference of 283. So this would be represented as: .283 kWh.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 5 Electrical Outlets Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What does a plan show about electrical outlets? It shows, in a simple manner, the location and type of outlet, switch, or special electrical device needed. 2. What is an outlet? A point on the wiring system at which current is taken to supply utilization equipment. 3. Match the following switch types with the proper symbol. a. single-pole Sp b. three-way S4 c. four-way S d. single-pole with pilot light S3 4. The plans show curved lines running between switches and various outlets. What do these curved lines indicate? The outlets that are controlled by the switches. 5. Why are the lines mentioned in Question 4 usually curved? To distinguish them from visible lines. 6. a. What are junction boxes used for? For joining two or more cables or conduits. b. Are junction boxes normally used in wiring the first floor? No. The CEC, Part I, requires that they be installed so that the cover openings are accessible. Note: The requirements for accessibility would mar the appearance of the living quarters; therefore, connections are usually made in outlet boxes. c. Are junction boxes normally used to wire exposed portions of the basement? Yes. The installation will not spoil the appearance of the basement. 7. How are standard sectional switch (device) boxes mounted? The boxes can be nailed or screwed to a structural member or wood backing or mounted to brackets or metal mounting strips or adjustable bar hangers.

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8. a. What is an offset bar hanger? An offset bar hanger is a device on which boxes are fastened so they can be mounted between joists or studs. The hangers are available in adjustable types for different joist spacing. b. What types of boxes may be used with offset bar hangers? Practically any outlet or switch box with a ½ -inch knockout can be used with offset bar hangers. 9. What methods may be used to mount lighting fixtures to an outlet box fastened to an offset bar hanger? Either a fixture stud or the No. 8-32 screw holes in the box can be used. Fixtures are usually furnished with some means to fasten the fixture to the box using either one or both of these methods. Section 30-302(3). 10. What is the size of the opening of a switch (device) box for a single device? 3” x 2”. Single sectional box sizes are found in Table 23. 11. The space between a door casing and a window casing is 89 mm. Two switches are to be installed at this location. What problems could you encounter when placing the switches in this location? What would you recommend as a possible solution? The space is too small for a two-gang face plate; therefore, the switches must be mounted one above the other vertically or one of them relocated to another location. 12. Three switches are mounted in a three-gang switch (device) box. The wall plate for this assembly is called a three-gang, three-hole switch plate. 13. [Circle the correct answer.] For each fixture stud inside a box, (increase) (decrease) the number of conductors allowed by one. 14. a. How high above the finished floor are the switches located in the garage of this dwelling? 1200 mm to centre. b. In the living room of this dwelling? 1300 mm to centre. 15. How high above the finished floor are the receptacle outlets in the garage located? 1200 mm In the living room? 300 mm 16. Outdoor receptacle outlets in this dwelling are located 450 mm above grade.

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Electrical Wiring: Residential, Seventh Canadian Edition

17. In the spaces provided, draw the correct symbol for each of these items: a. Lighting panel

or LP

b. Clock outlet

LP

c. Duplex outlet d. Outside line telephone e. Single-pole switch

or

f. Four-way switch

or

g. Duplex outlet, split-circuit

Drawing symbol

h. Lampholder with pull switch i. Weatherproof outlet j. Special-purpose outlet k. Fan outlet l. Range outlet m. Power panel

LP

n. Three-way switch

or

o. Pushbutton p. Thermostat q. Electric door opener

G

r. Multioutlet assembly

18. The front edge of a box installed in a combustible wall must be flush with the finished surface. Rule number? Rule 12-3016(1).

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19. List the maximum number of #12 AWG conductors permitted in a a. 4 × 1½-in. (102 × 38-mm) octagon box. 8 Table 23 b. 411/16 × 1½-in. (119 × 38-mm) square box. 17 Table 23 c. 3 × 2 × 2½-in. (76 × 51 × 64-mm) device box. 7 Table 23 20. Hanging a ceiling fixture directly from a plastic outlet box is permitted only if the carton or box is marked that the non-metallic box is CSA approved for that purpose. 21. It is necessary to count fixture wires when counting the permitted number of conductors in a box according to Rule 12–3034(1)(d). [Underline or circle the correct answer.] (True) (False) 22. CEC Table 23 allows a maximum of ten wires in a certain box. However, the box will have two wire connectors and one fixture stud in it. What is the maximum number of wires allowed in this box? 10 – 1 for two wire connectors = 9 9 – 1 for fixture stud = 8 wires maximum 23. When laying out a job, the electrician will usually make a layout of the circuit, taking into consideration the best way to run the cables and/or conduits and how to make up the electrical connections. Doing this ahead of time, the electrician determines exactly how many conductors will be fed into each box. With experience, the electrician will probably select two or three sizes and types of boxes that will provide adequate space to meet Code requirements. CEC Table 23 shows the maximum number of conductors permitted in a given size box. However, the number of conductors shown in the table must be reduced by 1 conductor(s) for two wire connectors by 1 conductor(s) for the fixture stud by 2 conductor(s) for each wiring device mounted on a single strap by 0 conductor(s) for one or more bare copper bonding conductors. Rule 12-3034(1,2) 24. Define the term bonding. Why is the installation of bonding conductors important? Bonding is a low impedance path obtained by permanently connecting all noncurrent-carrying metal parts to assure electrical continuity and having sufficient capacity to conduct safely any current likely to be imposed on it. Bonding ensures that all of the non-current-carrying metal parts of the electrical system are at the same potential.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 6 Determining the Number and Location of Lighting and Receptacle Branch Circuits Solutions to Review

1. A living room wall is 6 m long. How many receptacles are required for the wall? Two. 2. A hallway is 3 m long and has a doorway fitted at each end. Does this hallway require a receptacle? Yes. 3. A hallway is 6 m long and has an open doorway at each end. The hall opens onto two rooms that each has one receptacle within 1 m of the doorway. Does this hallway require a receptacle? No. No point in the hall is more than 4.5 m from a receptacle. 4. How many receptacles are required in an unfinished basement with an area of 63 m2? One. 5. A kitchen counter is 3 m long. A sink that is 600 mm is located in the exact centre of the counter. How many receptacles are required for the counter? Two. 6. How many of the receptacles in Question 5 require GFCI protection? Two. 7. A counter has an isolated work surface of 600 mm between a sink and a built-in oven. Is a receptacle required in this space? Yes. 8. How many luminaires or lampholders are required for an unfinished basement area that is 63 m2? Three, one for every 30 m2 or fraction thereof. 9. How many receptacles are required in an attached two-car garage? Two, one for each car space. 10. How many luminaries are required in an attached two- car garage? One. 11. When is a luminaire required for a stairway? All stairways are required to be lighted.

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12. When is switch control required at the top and bottom of a stairway? When there are four or more risers. Exception is single-dwelling unfinished basement with no exits. 13. When a stairway leads to an unfinished basement that has an outside exit, is a switch required at the top and bottom of the stairs? Yes. 14. When should a receptacle be provided for a central vacuum unit? When the ducting for the central vac is installed. 15. A receptacle in a utility room is supplied from its own circuit. Can the wiring from the receptacle be extended to supply eight outlets in a finished family room? No. A separate circuit is required for the utility room. 16. Why shouldn’t a freezer be placed on a circuit protected by a GFCI? Nuisance tripping of the GFCI will cause the freezer to lose power. 17. What outlets in a dwelling unit must have AFCI protection? All receptacles except bathrooms with basin, refrigerator, kitchen counter receptacles, kitchen island receptacle, peninsula, sump pumps of dwelling units. 18. A counter has three 5-20A receptacles. What is the minimum number of branch circuits that may be used for these receptacles? Two. 19. What is the minimum number of circuits that may be run to a laundry room? Minimum of one for the laundry room receptacles, one for the lighting, additional if electric dryer is supplied. 20. Does the receptacle located next to a washbasin in a bathroom have to be on its own circuit? No. This is not a requirement of the CEC.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 7 Conductor Sizes and Types, Wiring Methods, Wire Connections, Voltage Drop, Neutral Sizing for Services Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What is the largest size of solid wire that is commonly used for branch circuits and feeders? #10 AWG 2. What is the minimum size of branch-circuit conductor that may be installed in a dwelling unit? #14 AWG copper 3. What exceptions, if any, are there to the answer for Question 2? Wires used in lighting fixtures, bell wiring, and remote-control low-energy circuits. Section 16 and Table 12. 4. Define the term ampacity. The current carrying capacity of a wire expressed in amps. 5. What is the maximum voltage rating of all NMSC? 300 volts for non-metallic sheathed cable 6. Indicate the ampacity of these Type T90 Nylon (copper) conductors. Refer to Table 2. a. 14 AWG 25 amperes b. 12 AWG 30 amperes c. 10 AWG 40 amperes d. 8 AWG 55 amperes e. 6 AWG 75 amperes f. 4 AWG 95 amperes 7. What is the maximum operating temperature of these conductors? Give the answer in Celsius. (Use Tables 11 and 19.) a. Type TEW 60°C (Table 11, note 3) b. Type R90 90°C c. Type LVT 60°C d. Type DRT 60°C 8. What are the colours of the conductors in non-metallic-sheathed cable for a. two-wire cable? black, white, bare b. three-wire cable? red, black, white, bare

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9. For non-metallic-sheathed (Type NMD90) cable, can the uninsulated conductor be used for purposes other than bonding? No. 10. Under what condition may non-metallic-sheathed cable (Type NMD90) be fished in the hollow voids of stud walls? Where it is run as concealed wiring and not subject to excessive moisture. 11. a. What is the maximum distance permitted between straps on a cable installation? 1.5 m b. What is the maximum distance permitted between a box and the first strap in a cable installation? 300 mm 12. What is the difference between Type AC90 and Type TECK90 cable? TECK90 can be used in a wet location, while AC90 cannot. TECK90 also has a tighter spiral. Table 19. 13. [Fill in the blank and then circle the correct answer.] Type AC90 cable may be bent to a radius of not less than six times the diameter of the cable, measured to the (inside, outside) edge of the cable. 14. When armoured cable is used, what protection is provided at the cable ends? Anti-short bushings or other acceptable bushings of insulating material. Rule 12-610 (1)(a). 15. What protection must be provided when installing a cable in a notched stud or joist? The cable must be protected by a metal plate at least 1.59 mm thick (1/16 in). Rule 12-516(1)(a) and Appendix G. 16. Cables passing through a stud where the edge of the bored hole is less than 32 mm from the edge of the stud require additional protection. 17. a. Is non-metallic-sheathed cable permitted in your area for residential occupancies? Refer to local code and inspection department. b. From what source is this information obtained? The local regulatory authority. 18. [Circle the correct answer.] Is it permitted to use flexible metal conduit over 2 m long as a bonding means? (Yes) (No) 19. [Circle the correct answer.] Liquidtight flexible metal conduit (may) (may not) serve as a bonding means.

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Electrical Wiring: Residential, Seventh Canadian Edition

20. The allowable current-carrying capacity (ampacity) of aluminum wire is less than that of an equivalent copper wire. Use Rule 4-002 and Tables 2, 4, and 13 to complete the following table. Enter both ampacity and maximum overcurrent protection values.

WIRE #12 R90 #10 R90 #3 TW75 0000 TW 500 kcmil RW75

COPPER Ampacity Overcurrent Protection 30 30 40 40 100 100 230 250 380 400

ALUMINUM Ampacity Overcurrent Protection 35 35 45 45 115 125 280 300 485 500

21. [Circle the correct answer.] All solderless wire connectors are approved to connect aluminum and copper conductors together in the same connector. (True) (False) 22. Terminals of switches and receptacles marked CO/ALR are suitable for use with copper, aluminum, and copper-clad aluminum conductors. 23. When non-metallic-sheathed cables are bunched or bundled together for distances longer than 600 mm, what happens to their current-carrying ability? Their ampacity must be derated according to Table 5C. 24. A 120-volt branch circuit supplies a resistive heating load of 10 amperes. The distance from the panel to the heater is about 43 metres. Calculate the voltage drop using (a) #14, (b) #12, (c) #10, and (d) #8 AWG copper conductors. a. Ud = K I x L x 2/CMA = (39.4 x 10 x 43 x 2)/4110 = 8.24 volts b. Ud = K I x L x 2/CMA = (39.4 x 10 x 43 x 2)/6530 = 5.19 volts c. Ud = K I x L x 2/CMA = (39.4 x 10 x 43 x 2)/10380 = 3.26 volts d. Ud = K I x L x 2/CMA = (39.4 x 10 x 43 x 2)/16510 = 2.05 volts 25. In Question 24, it is desired to keep the voltage drop to 3% maximum. What is the minimum size wire that would be installed to accomplish this 3% maximum voltage drop? 3% of 120 volts is 3.6 volts. Therefore, the #10 AWG conductor or larger would be correct. Note to instructor: If time permits, you could ask the student to do a few calculations of the wattage output of the 10-amperes heater at the different voltages resulting from using different wire sizes.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 8 Switch Control of Lighting Circuits, Receptacle Bonding, and Induction Heating Resulting from Unusual Switch Connections Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. The identified grounded circuit conductor may be which colour? [Circle one.] State the CEC rule that specifies this. a. green b. white c. yellow d. grey e. green with yellow stripes Rule 4-030(1). 2. A T-rated switch may be used to its rated current capacity when controlling an incandescent lighting load. Rule 14-508(b) 3. What switch type and rating are required to control five 300-watt tungsten filament lamps on a 120-volt circuit? Show calculations. PT = 5 * 300 = 1500 W, So I = P/E = 1500/120 = 12.5A This circuit will need a Category 2 general purpose switch. 4. To control a lighting load from one control point, what type of switch would you use? Single-pole switch. 5. Single-pole switches are always connected to the ungrounded (HOT) wire. 6. Complete the connections in the following arrangement so that both ceiling light outlets are controlled from the single-pole switch. Assume the installation is in cable.

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7. a. Complete the connections for the diagram. Installation is cable.

b. Which conductor of the cable feeds the switch? c. Which conductor is used as the return wire? d. From which wire does the switch feed tap? e. What are the colours of the conductors connected to the fixture?

White Black Black Black and white

8. What type of switch is installed to control a lighting fixture from two control points? How many switches are needed? Three-way switches are required. Two three-way switches are needed.

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Electrical Wiring: Residential, Seventh Canadian Edition

9. Complete the connections in the following diagram so that the lamp may be controlled from either three-way switch.

Option #1

Option #2

10. Show the connections for a ceiling outlet to be controlled from any one of three switch locations. The 120-volt feed is at the light, Rule 4–036(2). Label the conductor colours. Assume the installation is in cable.

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2- conductor cable

3- conductor cable

11. Match the following switch types with the correct number of terminals for each. Three-way switch Two terminals Single-pole switch Four terminals Four-way switch Three terminals 12. When connecting single-pole, three-way, and four-way switches, they must be wired so that all switching is done in the ungrounded (HOT) circuit conductor. 13. If you had to install an underground three-wire feeder to a remote building using three individual conductors, which of the following installations “meets code”? [Circle correct installation.]

14. Is it always necessary to attach the bare equipment bonding conductor of a non-metallicsheathed cable to the green hexagonal bonding screw on a receptacle? Explain. Yes. The receptacle is fitted with the ground screw so that the bare copper bonding wire will be connected to the box first, then to the receptacle. This will ensure that if the receptacle is removed, the system is still bonded to ground. Rule 10-808(2).

15. When two non-metallic-sheathed cables enter a box, is it permitted to bring both bare bonding conductors directly to the bonding terminal of a receptacle, using the terminal as a splice point? No. A terminal may not have more than one wire connected to it, unless identified for such use.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 9 Ground-Fault Circuit Interrupters, Arc-Fault Circuit Interrupters, Transient Voltage Surge Suppressors, and Isolated Ground Receptacles Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Explain the operation of a GFCI. Why are GFCI devices used? Where are GFCI receptacles required? A ground-fault circuit interrupter (GFCI) senses an unbalanced current flow. An unbalanced current occurs when a ground fault exists. In other words, some of the current flow in a circuit is going to a grounded object from the hot conductor. This current flow may result in injury or death if it passes through a human being. The GFCI device interrupts the flow of current if an unbalanced current exists. A GFCI device may be an integral part of the branch-circuit breaker or part of the receptacle. Ground-fault protection supplied as part of the main service or a feeder is normally installed to protect electrical equipment against arcing ground faults. A ground-fault circuit interrupter is required where there is a possibility that a person will be operating electrical equipment, such as a drill, saw, electrical lawn mower or hair dryer, from a particular outlet. For example, this outlet could supply a swimming pool or receptacles outside the house or in a bathroom. 2. Residential GFCI devices are set to trip a ground-fault current of 6mA. 3. What are the residential applications of GFCI receptacles? GFCI-protected receptacles are required for all receptacles within 1.5 m of a sink, outside, and may also be used to replace two-wire duplex receptacles in renovation applications. Rules 26-700 (8,11), 26-710(n). 4. The CEC requires GFCI protection for certain receptacles in the bathroom. Explain where these are required. Any receptacle located within 1.5 m of a sink, bathtub, or shower stall must be GFCI protected. Rule 26-700(11).

5. Is it a CEC requirement to install GFCI receptacles in a fully carpeted, finished recreation room in the basement? Circle one. (Yes) (No) 6. A homeowner calls in an electrical contractor to install a separate circuit in an unfinished basement for a freezer. Is a GFCI receptacle required? No.

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7. GFCI protection is available as (a) a branch-circuit breaker GFCI, (b) a feeder-circuit breaker GFCI, (c) an individual GFCI receptacle, (d) a feedthrough GFCI receptacle. What type would you install for residential use? Explain your choice. (c) an individual GFCI receptacle, (d) a feedthrough GFCI receptacle. They have the lowest cost. 8. Extremely long circuit runs connected to a GFCI branch-circuit breaker might result in [circle the letter of the correct answer] a. nuisance-tripping of the GFCI. b. loss of protection. c. the need to reduce the load on the circuit. 9. If a person comes into contact with the hot and grounded circuit conductors of a two-wire branch circuit that is protected by a GFCI, will the GFCI trip? Why or why not? No. A GFCI trips only when there is a line-to-ground fault. It should be emphasized that GFCIs do not provide short-circuit protection. 10. What might happen if the line and load connections of a GFCI receptacle are reversed? The actual tripping mechanism is on the load side of the line supply terminals. If the 120-volt circuit were to be connected to the load terminals, should a ground-fault occur on the downstream device, the GFCI would trip off. All downstream devices would be de-energized, but the GFCI itself would still be energized. If the fault occurred at the GFCI receptacle, it would not trip off. 11. May a GFCI receptacle be installed on a replacement in an old installation where the twowire circuit has no bonding conductor? Circle one. (Yes) (No) 12. What two types of receptacles may be used to replace a defective receptacle in an older home with knob-and-tube wiring where a bonding means does not exist in the box? A GFCI receptacle or a grounding receptacle protected by a Class A GFCI or effectively bonded to ground. Rule 26-700 (7,8). 13. You are asked to replace a receptacle. Upon checking the wiring, you find that the wiring method is conduit and that the wall box is properly bonded. The receptacle is of the older style two-wire type that does not have a bonding terminal. You remove the old receptacle and replace it with [circle the letter of the correct answer] a. the same type of receptacle as the type being removed. b. a receptacle of the bonding type. c. a GFCI receptacle. 14. What colour are the terminals of a standard bonding-type receptacle? The “HOT” terminal is brass colour; the grounded circuit conductor terminal is white or silver; the bonding terminal is green. 15. What special shape are the bonding terminals of receptacle outlets and other devices? The bonding terminal is hexagon-shaped (six sides).

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Electrical Wiring: Residential, Seventh Canadian Edition

16. Why are GFCI receptacles installed on construction sites? Some of the hazards that may be encountered on a construction site are shock hazard from temporary wiring; workers standing in water; working in close proximity to or in contact with steel framing; electric cords and cables subject to severe mechanical abuse. 17. In your own words, explain why the CEC does not require receptacle outlets in garages and basements to be GFCI-protected. Nuisance-tripping. Where there are cord-connected appliances such as freezers, garage door openers, and refrigerators, the normal or slightly above-normal leakage currents might nuisance-trip the GFCI. 18. What do the letters TVSS stand for? transient voltage surge suppression 19. Transients (surges) on a line can cause spikes or surges of energy that can damage delicate electronic components. A TVSS device contains one or more metal-oxide varistors that bypass and absorb the energy of the transient. 20. Undesirable noise on a circuit can cause computers to lock up or lose their memory, and/or can cause erratic performance of the computer. This noise does not damage the equipment. The two types of this noise are EMI and RFI. What do these letters mean? EMI means electro-magnetic interference RFI means radio frequency interference 21. Can TVSS receptacles be installed in standard device boxes? Yes. 22. When an isolated ground receptacle is installed, the CEC permits the separate equipmentbonding conductor to be carried back through the raceway or cable to the distribution panel. What section of the CEC references this topic? Rule 10-904(8) 23. Briefly explain the difference between a GFCI breaker and an AFCI breaker. A GFCI breaker monitors the current in line and identifies conductors. If the difference exceeds 6 mA, the breaker de-energizes the circuit. An AFCI breaker monitors the voltage and current signatures associated with arcing faults. If an arcing fault is detected, the breaker de-energizes the circuit.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 10 Lighting Fixtures and Ballasts Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Is it permissible to install a recessed fixture directly against wood ceiling joists? Explain why or why not. No, due to the heat over time this will dry out the wood and lead to combustion. 2. If a recessed fixture without an approved junction box is installed, what extra wiring must be provided? The fixture must be wired with conductors having temperature ratings suitable for the temperature at the fixture. These conductors must be installed in a raceway at least 450 mm long but not more than 2 m long. A junction box must be provided at least 300 mm from the fixture. Rule 30-910. 3. Recessed fixtures are available for installation in direct contact with thermal insulation. These fixtures bear the CSA mark “Type IC.” 4. Unless specially designed, all recessed incandescent fixtures must be provided with factory-installed thermal protection. 5. Plans require the installation of a surface-mounted fluorescent fixture on the ceiling of a recreation room that is finished with low-density ceiling fibreboard. What sort of mark would you look for on the label of the fixture? CSA or other acceptable approval logo and have a maximum temperature rating of 90ᴼC. 6. If a recessed fixture bears no marking that it is listed for branch-circuit feedthrough wiring, is it permitted to run the circuit conductors from fixture to fixture? What section of the CEC covers this? No, it is not permitted to run branch feedthrough wiring. Section # 30-910(8). 7. Fluorescent ballasts for all indoor applications must be Class P type. These ballasts contain internal thermal protection to protect against overheating.

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8. You are called on to install a number of lighting fixtures in a suspended ceiling. The ceiling will be dropped about 200 mm from the ceiling joists. Briefly explain how you might go about wiring these fixtures. The branch-circuit wiring is installed above the suspended ceiling using standard wiring methods, such as EMT, NMSC, or AC90 cable. This depends upon the local electrical codes. Outlet boxes are installed above the ceiling, usually on the bottom or sides of the ceiling joists. The boxes are located near the location of the suspended ceiling “lay in” fixtures. From the outlet boxes, NMSC, armoured cable, or flexible metal conduit as applicable can be run to the knockouts on the fixture. These flexible connections are not to exceed 2 m. In the case of the NMSC and armoured cable, a staple or strap must be installed within 300 mm or the outlet box. It is recommended that the same be done for the flexible metal conduit. The conductor temperature rating must be suitable for the temperature requirements as stated on the fixture label. The fixtures are hoisted up and positioned so as to lay in the “T” bars of the ceiling grid. The fixtures must be securely fastened to the suspended ceiling grid. The fixtures must be securely fastened to the suspended ceiling metal framing members with clips, screws, or bolts. It is also a requirement in most localities that the fixture have an independent means of support other than the ceiling; this is usually jack chain and “S” hooks, which will support the fixture so that in the event of a fire, earthquake, or ceiling collapse from a similar problem, the fixture will not fall down onto someone’s head. If the fixtures have an internal connection box, such as in the case of many potlights, cable and /or conduit may be connected directly to the fixture. The outlet boxes indicated above may be eliminated in this case. 9. The CEC places a maximum open circuit voltage on lighting equipment in homes. [Circle the correct answer.] The maximum voltage is (300) (600) (750) (1000). Where in the CEC is this voltage maximum referenced? 150 volts-to-ground. Rules 2-106, 30-102. 1000 volts. Rule 30-802 gives this specific reference to electric discharge lighting.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 11 Branch Circuits for the Bedrooms, Study, and Halls Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Why do some electricians prefer to have more than one circuit feeding a room? It is good practice in large areas to have more than one circuit feeding the lighting circuits because if there is a problem on one circuit all power to the room is not lost. 2. Is it good practice to have outlets on different floors on the same circuit? Why? No, this is not recommended. In some localities it is against local code regulations. 3. What usually determines the grouping of outlets into a circuit? • CEC requirements for maximum number of outlets • Ease of wiring • Installation costs 4. The continuous load on a lighting branch circuit must not exceed 80 % of the branchcircuit rating. 5. To determine the maximum number of outlets in a circuit, 1.0 amperes per outlet are allowed. For a 15-ampere circuit, this results in a maximum of 12 outlets. 6. For this residence, what are the estimated wattages used in determining the loading of Branch-Circuit A16? Receptacles 120 watts (volt-amperes) Closet recessed fixture 60 watts (volts-amperes) 7. With respect to Rule 8–104(1), the ampere rating of Circuit A16 is 15 amps. 8. What size of wire is used for the lighting circuit in the front bedroom? #14 AWG 9. How many receptacles are connected to this circuit? 10 receptacles 10. What main factor influences the choice of wall boxes? The number of conductors entering and leaving the box and the devices to be mounted to the box. 11. How is a wall box grounded? By installing NMSC or AC90 cable, which contains a bare copper bonding conductor. This conductor is connected to the separate bonding screw in the box.

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12. What is a split-switched receptacle? A duplex receptacle with one outlet connected directly to the hot wire, which is on continuously. The other outlet is connected to the wire that is controlled by the switch. Split-circuit receptacles may also be used for individual circuiting of each outlet. 13. Is the switched portion of an outlet mounted toward the top or the bottom? Why? The switched portion is mounted at the bottom so that any lamp cord plugged into the switched section does not hang in front of the unswitched portion. 14. The following questions pertain to lighting fixtures in clothes closets. a. Does the CEC allow bare incandescent lamp fixtures such as porcelain keyless or porcelain pull-chain lampholders to be installed? No b. Does the CEC allow bare fluorescent lamp fixtures to be installed? No c. Does the CEC permit pendant fixtures or pendant lampholders to be installed? No. Rule 30-204. 15. How many switches are in the front bedroom circuit, and of what type are they? Three single-pole, single-throw. 16. The following is a layout of the lighting circuit for the front bedroom. Using the cable layout shown in Figure 11–6, make a complete wiring diagram of this circuit. Indicate the colour of each conductor.

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Electrical Wiring: Residential, Seventh Canadian Edition

17. When planning circuits, how should you divide loads? Loads are divided as evenly as possible among circuits, and there is a maximum of 12 outlets on a two-wire circuit. 18. The CEC uses the terms watts, volt-amperes, and kW. Explain their significance in calculating loads. On an AC circuit, the only time that watts equals volt-amperes, or when kW equals kVA, is for a pure resistive circuit (100% power factor). If wattage values are used for calculations for other than resistive loads (such as motor load), it is likely that a smaller current draw than the actual value will be calculated. Using VA and kVA values ensures that the actual current draw will be obtained. 19. How #14 AWG conductors are permitted in a device box that measures 76 × 51 × 64 mm (3 × 2 × 2½ in.)? Eight #14 AWG.

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20. A 102 × 38 mm (4 × 1½ in.) octagon box has one cable clamp, one fixture stud, and three wire connectors. How many #14 AWG conductors are permitted? Box 10 Less one for connectors -1 Less one for stud -1 Total 8 Clamps don’t count. Rule 12-3036(5). 21. What circuit supplies the master bedroom? A 14 22. For the recessed closet fixtures, what wattage was used for calculating their contribution to the circuit? 60 watts each; total 120 watts (150 VA) 23. What is the estimated load in volt-amperes for the circuit supplying the master bedroom? 920 volt-amperes 24. The sliding door in the master bedroom could affect the number of required receptacle outlets. Answer the following statements True or False. a. Sliding glass panels are considered to be wall space. False b. Fixed panels of glass doors are considered to be wall space. False. Any space occupied by glass panels that extend to the floor, as is the case with most patio doors, are not considered to be usable wall space. 25. What type of receptacle will be installed outdoors, just outside of the master bedroom? A GFCI receptacle protected by a weatherproof cover. 26. Based on the total estimated load calculations, what is the current draw on the study/bedroom lighting circuit? I = VA/E = 700 = 5.83 Amperes 120 27. The study/bedroom is connected to Circuit A16 lighting, A18 AFCI receptacles. 28. The conductor for this circuit is #14 AWG copper.

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Electrical Wiring: Residential, Seventh Canadian Edition

29. Is it necessary to install a receptacle in the wall space leading to the bedroom hallway? Rule 26-712(c) includes as usable wall space sections that are 900 mm or greater in width. In order to satisfy this requirement, a receptacle should be installed. 30. Show calculations needed to select a properly sized box for the receptacle outlet mentioned in Question 29. Non-metallic-sheathed cable is the wiring method. Refer to Quick-Check Box Selector Guide, Figure 5-16 in Unit 5. # Conductors from figure a14-1 4 # Wire Connectors 0 # Devices on Single Strap 1 Therefore, 2 additional conductors Total 6 conductors A standard 3 x 2 x 2-1/2 box would be suitable. The smallest size box permitted would be 3 x 2 x 2. 31. Using the cable layout shown in Figure 11–13, make a complete wiring diagram of Circuit A16.

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32. The following is a layout of the lighting circuit for the master bedroom. Using the cable layout shown in Figure 11–12, make a complete wiring diagram of this circuit. Indicate the colour of each conductor.

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Electrical Wiring: Residential, Seventh Canadian Edition

NOTE: The switch boxes that house the 3W and S/P need to be deep boxes as the wire count is high so you need deeper boxes. 33. Using the electrical plans supplied with this text, lay out the devices and wiring in the master bedroom according to minimum CEC standards. Review the diagram to see if okay.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 12 Branch Circuits for the Living Room and Front Entry Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. How many convenience receptacles are connected to the living room circuit? Nine. 2. a. How many wires enter the switch box at the four-way switch location? # Conductors from Figure 12-1 6 # Wire connectors 0 # Devices on single strap 1 therefore, 2 additional conductors Total 8 conductors b. What type and size of box may be installed at this location? A standard 3 x 2 x 2-1/2 box would be suitable. 3. a. What is meant by incandescent lamp inrush current? The cold resistance of a tungsten filament lamp is very low. When the lamp is energized, an extremely high in-rush current results. The temperature and resistance of the tungsten filament increase very rapidly and reduces the current to normal levels. T-rated switches are required on tungsten loads. b. Does the CEC require T-rated switches for incandescent lamps in dwelling units? Rule 14-508(b). 4. Complete the wiring diagram for the dimmer and lamp.

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5. What is the difference between a split-switched receptacle and a split-wired (three-wire) receptacle? A split-switched receptacle has one circuit with one half of a duplex receptacle switched and the other half live. A split-wired receptacle has two separate circuits feeding the duplex receptacle. 6. How many branch circuits are required for 1. a split-switched receptacle? One. 2. a split-wired (three-wire) receptacle? Two. 7. Explain why fluorescent lamps having the same wattage can draw different current values. The current ratings must be checked for various types of ballasts because the current draw depends on the power factor of the ballast-lamp combination. The lower the power factor rating, the higher the current draw. 8. What is the total current consumption of the track lighting? I = VA/E = 200/120 = 1.67 amperes 9. a. How many television outlets are provided in the living room? Three. b. What symbol is used on the drawing to indicate the TV outlet? The symbol for the TV outlet can be found in Figure 2-10E of Unit 2 of the textbook. TV

10. a. Where is the telephone outlet located in the living room? On the wall between the master bedroom and living room. b. What symbol is used on the drawing to indicate the telephone outlet? The symbol for the telephone outlet can be found in Figure 2-10E of Unit 2 of the textbook.

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11. A layout of the outlets, switches, dimmers, track lighting, and recessed fixtures is shown in the following diagram. Using the cable layout shown in Figure 12-1, make a complete wiring diagram of this circuit. Use coloured pencils or marking pens to indicate conductors.

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12. Must track lighting always be fed (connected) at one end of the track? No, the track may be fed at any point on the track using approved fittings. 13. If there is a 7-m piece of track lighting, how many outlets is this considered to have? (7 m is 23 ft.) Rule 8-2001(a). Determine by branch connected devices. Not to exceed 12 amperes. Also track fixture size to be considered. 14. Using the electrical plans provided, lay out devices and wiring in the living room area to minimum CEC standards. Since there are many variations of acceptable layouts, each will have to be evaluated independently.

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15. a. How many circuit wires enter the front entry ceiling box? Five. b. How many equipment bonding conductors enter the front entry ceiling box? Two. 16. How many receptacle outlets and lighting outlets are supplied by Circuit A15? Feed from the six gang box, the following spread to this feeder is as follows: Feeding the recess closet light (1) Ceiling fixture in entry area (1) Living room track light (1) The porch bracket fixture (1) The two-bracket fixture in the front of the garage (2) One receptacle outlet in the entry (1) Post light in the front lawn (1) Table 12-2 lays this out. Total: 8 17. Outdoor fixtures directly exposed to the weather must be marked as [circle the correct answer] a. suitable for damp locations. b. suitable for dry locations only. c. suitable for wet locations. 18. Make a materials list of all types of switches and receptacles connected to Circuit A15. • One duplex receptacle • Five single-pole switch • One single-pole incandescent dimmer • Two three-way switches 19. The following layout is for lighting Circuit A15, the entry, porch, and front garage lights. Using the cable layout shown in Figure 12–15, make a complete wiring diagram of this circuit. Use coloured pencils to indicate the colour of the conductors’ insulation.

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20. Using the electrical plans provided with this text, lay out the devices and wiring, including circuit numbers, for the front porch and entry to minimum CEC standards. Since there are many layout possibilities that will meet the minimum standards of the CEC, the instructor must evaluate each student’s answers.

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Unit 13 Branch Circuits for Bathrooms Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Most appliances of the type commonly used in bathrooms, such as hair dryers, electric shavers, and curling irons, have two-wire cords. These appliances are double insulated. Rule 10-408(3) and Appendix B. 2. The CEC requires that all receptacles in bathrooms be GFCI protected. 3. Draw the symbol or other markings used to identify double-insulated equipment. Rule 10-408(3) and Appendix B.

BATHROOM CEILING HEATER CIRCUITS

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1. What is the wattage rating of the heat/vent/light/night light? 120 x 14.9 = 1788 watts 2. To what circuits are the heat/vent/lights connected? A11 and A13 3. What type of box would you use for the rough-in of the switch assembly for the heat/vent/light? Two-gang switch boxes, which can accommodate the switches for the AK965 unit and a single gang for the vanity light. Why? As required by the manufacturer of the heat/vent/light/night-light combination unit (AK965) supplied by Air King ventilation products. 4. a. How many wires are required to connect the control switch and the heat/vent/light/night light? Five + bonding conductor. b. What size of wires are used? #12 AWG 5. Can the heating element be energized when the fan is not operating? No. Separate heater fan comes on with heater. 6. Can the fan be turned on without the heating element? Yes. Unit has separate ventilating fan. 7. What device can be used to provide automatic control of the heating element and the fan of the heat/vent/light? Thermostat

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8. Where does the air enter the heat/vent/light? Through the outer grille. 9. Where does the air leave this unit? Air is exhausted through the discharge duct. 10. Who is to furnish the heat/vent/light? The electrical contractor. See the specification, Appendix A. 11. For a ceiling heater rated 1200 watts at 240 volts, what is the current draw? I = P/E = 1200/240 = 5 amperes

HYDROMASSAGE BATHTUB CIRCUIT

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1. What circuit supplies the hydromassage bathtub? A9 2. Should the circuit supplying the hydromassage bathtub have GFCI protection? Yes. Rule 68-302. 3. What conductor size feeds the hydromassage tub? #14 AWG 4. What is the fundamental difference between a hydromassage bathtub and a spa? Hydromassage bathtub: Fill – use – drain. Spa: Fill – use – do not drain after each use. 5. What rules of the CEC refer to hydromassage bathtubs? Rules 68-300 to 68-308. 6. Must the metal parts of the pump and power panel of the hydromassage tub be grounded? Yes, they must be bonded to the ground. 7. Where should the electric controls be located for the hydromassage tub? The on-off device must be located not less than 1 m horizontally from the wall of the hydromassage bathtub, unless it is behind a barrier.

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8. Complete the wiring diagram below.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 14 Lighting Branch Circuit and Small-Appliance Circuits for the Kitchen Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What provision does the CEC require for microwave ovens in enclosures? A receptacle on a separate circuit. What is the relevant rule number? Rules 26-710 (h)(iii)(v) and 26-722(d). 2. What circuit feeds the kitchen lighting? What size of conductors is used? Panel B circuit B7. #14 AWG copper wire. 3. How many lighting fixtures are connected to the kitchen lighting circuit? Six, plus light in range hood. 4. Which colour of fluorescent lamps are recommended for residential installations? Deluxe warm white (WWX), or warm white (WW), or deluxe cool white (CWX). 5. a. What is the minimum number of 15-ampere split circuits or 20-ampere circuits required for a kitchen according to the CEC? Rule 26-712 (d)(iii,iv,v): (iii) a sufficient number of receptacles (5-15R split or 5-20R) along the wall at counter work surfaces (excluding sinks, built-in equipment, and isolated work surfaces less than 300 mm long at the wall line) so that no point along the wall line is more than 900 mm from a receptacle measured horizontally along the wall line; (iv) at least one receptacle (5-15R split or 5-20R) installed at each permanently fixed island counter space with a continuous long dimension of 600 mm or greater and a short dimension of 300 mm or greater; (v) at least one receptacle (5-15R split or 5-20R) installed at each peninsular counter space with a continuous long dimension of 600 mm or greater and a short dimension of 300 mm or greater. b. How many are there in this kitchen? 2-20A circuits. B13 and B15.

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6. How many duplex receptacle outlets are provided in the kitchen? 3 5-20RA on the wall behind the counter. 1 5-20RA on the island. 1 5-15R in the eating area of the kitchen. 1 5-15 R for the microwave +1 5-15R for the refrigerator 7 in total 7. What is meant by the term split-circuit receptacle? A receptacle to which two circuits may be connected. Each outlet of the receptacle is capable of being connected to a separate circuit. The CEC calls this a multiwire branch circuit. Also, part of the split-circuit receptacle may be switch-controlled. 8. A single receptacle connected to a circuit must have a rating not less than the ampere rating of the circuit. 9. In kitchens, receptacles along the countertop must be installed no farther than 900 mm apart. Rule 26-712(d)(iii) 10. A fundamental rule regarding the grounding of metal boxes, fixtures, and so on is that they must be grounded when “in reach of a grounded surface.” Rule 26-712(d) 11. How many circuit conductors enter the box a. in the track lighting ceiling box over the eating area? 9 b. at the two-gang switch located to the right of the sliding door? 13 12. How much space is there between the countertop and upper cabinets? 750 mm 13. Where is the speed control for the exhaust fan located? On the range hood unit. 14. Who furnishes the range hood? Electrical contractor; see specifications. 15. List the appliances in the kitchen that must be connected. Built-in oven; built-in countertop cooking unit; dishwasher; food waste disposer; range hood fan/light.

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16. Complete the wiring diagram below by connecting feedthrough GFCI 1 to protect receptacle 1, both to be supplied by Circuit A1. Connect feedthrough GFCI 2 to also protect receptacle 2, both to be supplied by Circuit A2. Use coloured pencils or pens to show insulation colours. Assume that the wiring method is EMT, where more freedom in the choice of insulation colours is possible.

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17. Each 15-ampere appliance circuit load demand shall be determined at [circle one] (1440 watts) (1500 watts) (1800 watts). 18. It is permitted to connect an outlet supplying a clock receptacle to the branch circuit dedicated to the refrigerator circuit. [Circle one.] (True) (False) True. If the receptacle is a recessed clock receptacle. Rule 26-722(a). 19. a. It is permitted to connect a receptacle in the dining area of a kitchen to one of the kitchen split circuits. [Circle one.] (True) (False) What CEC rule applies to this situation? Rule 26-724(b)(ii). b. Receptacles located above the countertops in the kitchen must be supplied by at least two 15-ampere, three-wire circuits. 20. The following is a layout for the lighting circuit for the kitchen. Complete the wiring diagram using coloured pens or pencils to show the conductors’ insulation colour.

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21. a. According to Rule 26–712(a), no point along the floor line shall be more than 1.8 m from a receptacle outlet. b. According to Rule 26–712(c), a receptacle must be installed in any wall space 0.9 m wide or greater. 22. The CEC states that in multiwire circuits, the screw terminals of a receptacle must not be used to splice the neutral conductors. Why? Quote the rule number. This is so that the receptacle may be removed without breaking the identified conductor circuit to the next receptacle. Section 4-036 (4). 23. Exhaust fans produce noise. It is possible to compare the noise levels of different fans before installation by comparing their sone ratings. 24. Is it permitted to connect the white grounded circuit conductor to the grounding terminal of a receptacle? No.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 15 Special-Purpose Outlets for Ranges, Counter-Mounted Cooking Units , Wall-Mounted Ovens Food Waste Disposals , and Dishwashers

,

Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. COUNTER-MOUNTED COOKING UNIT CIRCUIT 1. a. What circuit supplies the counter-mounted cooking unit in this residence? B2-4 b. What is the rating of this circuit? 40 amperes 2. What methods may be used to connect counter-mounted cooking units? • By running the supply cable to a junction box attached to the appliance. • By running the supply cable to a junction box attached to a length of flexible conduit furnished by the appliance manufacturer. • By running the supply cable to a range receptacle of adequate capacity, then attaching a cord set to the appliance. (This cord set is usually supplied with new appliances.) Rules 26-710(h), 26-744(7). 3. Is it permissible to use standard 90°C insulated conductors to connect all countermounted cooking units? Why? Not necessarily. Check the appliance label to see if there is a requirement for a conductor with a higher temperature rating. 4. Indicate the maximum operating temperature (in degrees Celsius) for the following. a. Type TW conductors 60°C b. Type TWN75 conductors 75°C c. Type R90 conductors 90°C 5. May NMWU cable be used to connect counter-mounted cooking units? Yes, as long as the cable is sized from the appropriate table to carry the correct ampacity based on the rating of the appliance and the unit nameplate indicates the supply conductors may be rated for 60°C. 6. a. What CEC rule applies to bonding a counter-mounted cooking unit? Rule 10-400 b. How is the counter-mounted cooking unit bonded to ground? Through a separate bonding conductor run with the circuit conductors.

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7. a. What is the mounting height of the receptacle supplying a range? Not to exceed 130 mm to the centre of the receptacle. Rule 26-744(6)(a). b. In which direction should the U-ground slot be oriented? Either side. Rule 26744(6)(c). c. Give the CEC section number and rule. Rule 26-744(6)(a,c). 8. When the voltage to an element is doubled, the wattage [circle one] a. increases. b. decreases. 9. One kilowatt equals 3412 Btu per hour. 10. How much heat will a 1000-watt heating element produce if operated continuously for 1 hour? 3114 x 24 x 365 = 27,278,640 BTU WALL-MOUNTED OVEN CIRCUIT

F

1. To what circuit is the wall-mounted oven connected? Circuit B6-8. 2. An oven is rated at 7.5 kW. This is equal to a. 7500 watts. b. 31.2 amperes at 240 volts. 3. a. What section of the CEC governs the bonding of a wall-mounted oven? Rule 10-400. b. How are wall-mounted ovens bonded to ground? Through a separate bonding conductor run with the circuit conductors. 4. What is the type and rating of the overcurrent device protecting the wall-mounted oven? Two-pole, 40-ampere, 240-volt circuit breaker. 5. How many metres of cable are required to connect the oven in the residence? 4 m Note: Connection point at oven is unknown; therefore, vertical measurement is from bottom of panel to top of oven, approximately 3 m, horizontal measurement is approximately 700 mm, and 300 mm is allowed for connections.

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6. When connecting a wall-mounted oven and a counter-mounted cooking unit to one feeder, how long are the taps to the individual appliances? a. The conductors feeding a fixed cooking appliance may tap off from a singlebranch circuit. If the taps do not exceed 7.5 m, their ampacity may be based on the exact amp rating of the unit they supply. If, however, their length exceeds 7.5 m, these taps must be the same size as the feeder from which they are tapped. These taps can in no case be smaller than one-third the size of the main branch circuit conductor from which they branch out. Rule 26-742(c). 7. A 6-kW counter-mounted cooking unit and a 4-kW wall-mounted oven are to be installed in a residence. Calculate the demand according to Rule 8–300(1). Show all calculations. 6 kW + 4 kW = 10 kW For a load not over 12 kW, the maximum demand may be considered as 8 kW, or 8000 watts. Rule 8-300 (1,2). 8. What size conductors will feed a. from the panel to the junction box? 8kW/240 = 33.3 amperes. Use #10 NMD90. Rated from the 75ᴼC Column. b. each of the individual units in Question 7? 6 kW – If less than 7.5 m (6000/240 = 25 amperes), use #12 NMD 90. Rated from the 75ᴼC Column. 4 kW – If less than 7.5 m (4000/240 = 16.6 amperes), use #14 NMD90. Rated from the 75ᴼC Column. 9. a. A freestanding range is rated at 11.8 kW, 240 volts. According to Rule 8–300(1), what is the demand? 8kW b. What size wire (Type NMD90) is required? #8 AWG. Rated from the 75ᴼC Column. c. What type of receptacle is required for the range? 14-50R FOOD WASTE DISPOSAL CIRCUIT DISPOSALS

H

1. How many amperes does the food waste disposal draw? 7.2 amperes 2. a. To what circuit is the food waste disposal connected? B19 b. What size wire is used to connect the food waste disposal? #14 AWG 3. Means must be provided to disconnect the food waste disposal. The homeowner need not be involved in electrical connections when servicing the disposal if the disconnecting means is a plug cap and receptacle. 4. How is running overcurrent protection provided in most waste disposal units? By built-in thermal protection.

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5. Why are flow switches sometimes installed on food waste disposals? To ensure that enough cold water flows when the food waste disposer is used. 6. What CEC sections relate to the grounding of appliances? Rule 10-400. 7. Do the plans show a wall switch for controlling the food waste disposal? Yes. 8. A separate circuit supplies the food waste disposal in this residence. How many metres of cable will be required to connect the disposal? 3.5 m DISHWASHER CIRCUIT I 1. a. To what circuit is the dishwasher in this residence connected? B15 b. What size wire is used to connect the dishwasher? #14 AWG 2. The motor on the dishwasher is [circle one] a. ¼ hp. b. ⅓ hp. c. ½ hp. 3. The heating element is rated at [circle one] a. 750 watts. b. 1000 watts. c. 1250 watts. 4. How many amperes at 120 volts do the following heating elements draw? a. 750 watts 6.25 amperes b. 1000 watts 8.33 amperes c. 1250 watts 10.4 amperes 5. How is the dishwasher in this residence grounded? Through a separate bonding conductor run with the circuit conductors. In NMSC, this is the bare conductor in the cable. 6. What type of cord is used on most portable dishwashers? Three-wire flexible cord that is suitable for damp locations; for example, SJ or SJO as listed in Table 11. 7. How is a portable dishwasher grounded? Through the bonding conductor in the flexible cord supplying the dishwasher. 8. a. What is double insulation? Two separate insulations are provided between the hot conductor and the person using the appliance or tool.

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b. What is the symbol for double insulation?

Square within a square. Rule 10-408(3), Appendix B. 9. Who is to furnish the dishwasher? The homeowner. See the specification, Appendix A. 10. Does the CEC require a separate circuit for the dishwasher? No. It is commonly recommended that it is connected to a separate circuit so that any other loads will not be affected.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 16 Branch Circuits for the Laundry, Washroom, and Attic Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. DRYER CIRCUIT AND LAUNDRY ROOM CIRCUITS 1. List the switches, receptacles, and other wiring devices that are connected to Circuit B20. Single-pole switches 4 Single-pole switch with pilot light 1 Receptacles – GFCI type 1 Exhaust fans 2 Luminaires 2 Lampholders 4 2. What CEC rule(s) refers (refer) to the receptacle required for the laundry equipment? Briefly state the requirements. Rules 26-700(11), 26-710(e)(i,ii), 26-712(a), and 26-720(b). A receptacle is required in a space intended for a washing machine. At least one other receptacle is required in a laundry room. If the washing machine receptacle is within 1.5 m of a sink, it is to be inaccessible for use with general use appliances or GFCI-protected. 3. The receptacle outlets are connected to branch circuits that have been calculated to have a maximum load of ___ watts per circuit. Circle one: 1200, 1440, 1500 watts. a. What regulates the temperature in the dryer? thermostat b. What regulates the drying time? timer 4. What is the method of connection to an electric clothes dryer? The most common is a cord and receptacle combination rated at 125/250Volts @ 30 amperes 5. What is the unique shape of the neutral blade of a 30-ampere dryer cord set? It is L-shaped and is longer than the other two hot blades. 6. a. What is the minimum number of receptacle outlets that must be installed in a laundry room? Two b. Is a separate branch circuit required? Yes c. Quote the CEC rule numbers. Rules 26-710(e)(i,ii) and 26-722(b). 7. What is the maximum permitted current rating of a portable appliance on a 30-ampere branch circuit? 30 x 0.8 = 24 amperes

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8. What is the current draw of the exhaust fan in the laundry? I = VA/E = 90/120 = 0.75 amperes 9. What special type of switch controls the attic lights? A single-pole switch that has an integral light. 10. If an attic exhaust fan draws 12 amperes at 120 volts and the ambient temperature reaches 50°C, what size and type of wire will be required to feed the fan? Refer to CEC, Table 5A. 12/0.82 = 14.63-ampere wire (Table 5A, 90ᴼC column at 50ᴼC ambient). Therefore, #14/2 NMD-90 is acceptable. 11. When installing cables in an attic along the top of the floor joists, 1.0-m clearance must not be exceeded. Rule 12-514 (a). 12. The total estimated watts for a circuit has been calculated to be 1300 volt-amperes. How many amperes is this at 120 volts? I = VA/E = 1300/120 = 10.83 amperes 13. In what circumstances would lighting and/or power be provided in an attic? Where specified by the homeowner or the architect or where the attic may contain special equipment that may need to be serviced. 14. The following is a layout of the lighting circuit for the laundry, washroom, rear entrance hall, and attic. Complete the wiring diagram using coloured pens or pencils to indicate conductor insulation colour.

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ATTIC EXHAUST FAN CIRCUIT

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1. What is the purpose of the attic exhaust fan? To maintain the attic temperature at a level near to the outside air temperature. 2. At what voltage does the fan operate? 120 volts 3. What is the horsepower rating of the fan motor? ¼ HP 4. Is the fan direct-driven or belt-driven? Direct-driven. 5. How is the fan controlled? By a thermostat. 6. What is the setting of the running overload device? 7.25 amperes. 7. What is the rating of the running overload protection if the motor is rated at 10 amperes? 10 x 1.25 = 12.5 amperes

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8. What is the basic difference between a thermostat and a humidistat? A thermostat switching mechanism operates with a bimetallic element that is sensitive to changes in temperature. A humidistat contains a nylon element that is sensitive to changes in humidity to operate the switching mechanism. 9. What size of conductors are to be used for this circuit? #14 AWG 10. How many metres of cable are required to complete the wiring for the attic exhaust fan circuit? 9m 11. May the metal frame of the fan be grounded to the grounded circuit conductor? No 12. What CEC rule prohibits grounding equipment to a grounded circuit conductor? Rule 10-204 (1)(c).

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Unit 17 Electric Heating and Air Conditioning Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. ELECTRIC HEAT 1. a. What is the allowance in watts made for electric heat in this residence? 13 kW b. What is the value in amperes of this load? I= P/E = 13000/240 = 54.17 amperes 2. What are some of the advantages of electric heating? • Electric heating is safer than a fuel combustion system. • It is clean. • It has the capability for individual room control. • It is quiet in operation. • It requires a minimal amount of maintenance. 3. List the different types of electric heating system installations. Baseboard, wall-mounted, floor-mounted, embedded cable in ceiling or floor, central furnace, duct heaters, heat pumps. 4. There are two basic voltage classifications for thermostats. What are they? Line-voltage and low-voltage thermostats. 5. Which device is required when the total connected load exceeds the maximum rating of a thermostat? A relay of adequate capacity. 6. The electric heat in this residence is provided by what type of equipment? An electric furnace. 7. At what voltage does the electric furnace operate? 240 volts. 8. A certain type of control connects electric heating units to a 120-volt supply or a 240-volt supply, depending on the amount of the temperature drop in a room. These controls are supplied from a 120/240-volt, three-wire, single-phase source. Assuming that this type of device controls a 240-volt, 2000-watt heating unit, what is the wattage produced when the control supplies 120 volts to the heating unit? Show all calculations. P = E2 / R = (E x E) / R. If you solve for R = E2 /P, you get 28.8 ohms. The resistance of the baseboard never changes; all you can change is the amount of voltage you apply to it. If you use 28.8 ohms and multiply it by 120 volts, you get 500 watts. When the voltage is reduced to one-half the rated value, the wattage is reduced to one-quarter of its rated value.

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9. What advantages does a 240-volt heating unit have over a 120-volt heating unit? For the same wattage rating, the current draw at 240 volts is one-half of the current draw at 120 volts. This can result in the use of smaller conductors, smaller raceways, less voltage drop (IR), and less watts loss (I² R) in the conductors. 10. a. The white wire of a cable may be used to connect to a hot circuit conductor only if The white conductor is made permanently unidentified or cable is armoured cable, NMSC, or aluminum-sheathed cable used for S.P.S.T three-way or fourway switch loops. b. Quote the rule number. Rule 4-036(1)(2). 11. Electric baseboard heaters shall not be installed beneath wall receptacle outlets. Explain and quote the CEC rule. Receptacles should not be located so that the cord will pass over the baseboard heaters. Rule 26-712(a), Appendix B. 12. [Circle the correct answer.] The branch circuit supplying a heater shall have an ampacity of a. not less than the connected load supplied. Rule 62-110(1)(b) b. 125% of the current rating of the heater. 13. Compute the current draw of the following electric furnaces. The furnaces are all rated 240 volts. a. 7.5 kW I = P/E = 7500/240 = 31.25 amperes b. 15 kW I = P/E = 15000/240 = 62.5 amperes c. 20 kW I = P/E = 20000/240 = 83.3 amperes 14. The wattage output of a 240-volt electric furnace connected to a 208-volt supply will be about 75% of the wattage output if the furnace is connected to a 240-volt supply. Referring to Question 13, calculate the wattage output of (a), (b), and (c) if the furnace is connected to a 208-volt supply. a. 7.5 x 0.75 = 5.625 kW b. 15 x 0.75 = 11.25 kW c. 20 x 0.75 = 15 kW 15. A central electric furnace heating system is installed in a home. Should a separate branch circuit supply this furnace? Explain. Yes. Heating equipment is required to be on branch circuits devoted to heating equipment only. 16. What CEC rule provides the answer to Question 15? Rule 62-110(1)(a), Rule 62-114(1).

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AIR CONDITIONING 1. When calculating air-conditioner load requirements and electric heating load requirements, is it necessary to add the two loads together to determine the combined load on the service? Explain your answer. For loads that are not likely to be operated at the same time, the smaller of the two loads may be omitted. However, many inspection authorities require that the loads be interlocked such that only one load may operate at a time. Otherwise, both loads must be included. Rule 8-106 (4). 2. The total load of an air conditioner shall not exceed what percentage of a separate branch circuit? [Circle one of the following.] a. 75% b. 80% c. 125% 3. Do window air conditioners count as a connected load when calculating the demand watts on a service? Only if the total rating is greater than the heating load. Rule 8-200(1)(a)(iii). However, since these loads are not interlocked, many inspection authorities may require that both loads be included. 4. Must an air conditioner installed in a window opening be bonded to ground? Yes. 5. A 120-volt air conditioner draws 12 amperes. What size is the circuit to which the air conditioner will be connected? 15 amperes 6. When a central air-conditioning unit is installed and the label states “Maximum size fuse 50 amperes,” is it permissible to connect the unit to a 50-ampere circuit breaker? Only if the AC unit has a listing of 50 amperes for the circuit breaker as well. In other words, the overcurrent protection for a particular piece of equipment is listed on the label of the equipment in order for it to be certified by CSA. 7. What CEC rule prohibits installing Class 2 control circuit conductors in the same raceway as the power conductors? Rule 16-212(3). The Class 2 conductors may be run in the same raceway only if separated by an acceptable barrier.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 18 Oil and Gas Heating Systems Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. How is the residence in the text heated? Electric heat (furnace). 2. Where does the CEC require that a disconnecting means be installed for a furnace or boiler? It requires that the disconnecting means be located between the furnace and the point of entry to the area where the furnace is located. Not to be located on the furnace. Rule 26-806(6,7). 3. What device in an oil-burning system will shut off the burner in the event of a flame-out? The primary control, sometimes called the “stack” switch. 4. Name the control that limits dangerous water temperatures in a boiler. Liquid immersion control. This is also provided through an aqua-stat, which connects to the outside of the water line leaving the boiler. 5. Name the control that limits the temperature in the plenum of a furnace. Limit control, sometimes called a limit switch. 6. In the wiring diagrams in this unit, are the safety controls connected in series or parallel? Series. 7. What is meant by the term “self-generating”? “Self-generating” means that the system does not require a separate power supply. The system generates its own power by means of a thermopile. 8. Because a self-generating unit is not connected to an outside source of power, the electrician need not use care in selecting the conductor size or making electrical connections. Is this statement true or false? Explain. False. Regardless of the type of burner to be installed, the electrician must always use care in making connections. Because the power in a self-generating system is very low, the circuit resistance must be kept as low as possible by using correct extension wire for the thermocouples and by ensuring that all connections are secure. 9. Explain what a thermocouple is and how it operates. A thermocouple is two unlike metals joined together so that a complete circuit is formed. Electric current will flow when one junction is heated and the other junction remains cold. This can then be calibrated to measure the temperature at the end of the thermocouple.

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10. Explain what a thermopile is. A thermopile is a series of thermocouples connected in series to produce a greater voltage and subsequently a greater current. 11. If Class 2 extra-low-voltage conductors are insulated for 32 volts, and the power conductors are insulated for 600 volts, does the CEC permit pulling these conductors through the same raceway? No. Rule 16-212(3). 12. If Class 2 extra-low-voltage conductors are used on a 24-volt system but are actually insulated for 600 volts (T90 nylon No. 14, for example), does the CEC permit running these conductors together in the same raceway as the 600-volt power conductors? No. Except if the power conductors are supplying power to the Class 2 circuit. Rule 16-212(4). 13. Under what conditions may Class 1 conductors and power conductors be installed in the same raceway? If insulated for the maximum voltage of any conductor, and connected to the same piece of equipment. 14. What is the CEC section and rule for Question 13? Rule 16-114(2).

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 19 Recreation Room Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What is the total current draw when all six fluorescent fixtures are turned on? I = VA/E = 936/120 = 7.8 amperes 2. How many #14 AWG conductors will enter the junction box that will be installed above the dropped ceiling near the fluorescent fixtures closest to the stairway? Seven total conductors: three from the switch (power, return and neutral); two going to the next branch light return and neutral; and two to feed the receptacle power and neutral. 3. Why is it important that the hot conductors in a three-wire circuit be properly connected to opposite phases in a panel? Because of the possibility of overloading the neutral conductor. 4. In the diagram, Load A is rated at 10 amperes, 120 volts, and Load B is rated at 5 amperes, 120 volts.

a. When connected to the three-wire circuit as indicated, how much current will flow in the neutral? The neutral carries the unbalanced load of 10 – 5 = 5 amperes. b. If the neutral should open, to what voltage would each load be subjected, assuming both loads were operating at the time the neutral opened? Show all calculations. Load A: R = E/I = 120/10 = 12 ohms Load B: R = E/I = 120/5 = 24 ohms With an open neutral, A and B are in series, therefore, RT = 12 + 24 = 36 ohms IT = E/RT = 240/36 = 6.66 amperes

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Therefore:

Load A: E = I x R = 6.66 x 12 = 80 volts Load B: E = I x R = 6.66 x 24 = 160 volts

Load B will be damaged due to high voltage. 5. Calculate the watts loss and voltage drop in each conductor in the following circuit.

15.24m #12 AWG SOLID COPPER

15 ampere

15.24m #12 AWG SOLID COPPER

1000 ft. of #12 AWG solid copper wire has 1.93-ohms resistance. Therefore, 50 ft. would have 0.0965-ohms resistance. Power = I x I x R = 15 x 15 x 0.0965 = 21.7 watts per wire. Voltage drop = I x R = 15 x 0.0965 = 1.4475 volts per wire. At 120 volts applied to the circuit, the 2.9 volts dropped on the wires is less than the 3.6 volts (3%) permitted by the Code. 6. Unless specifically designed, all recessed incandescent fixtures must be provided with factory-installed marking to indicate if the fixture is suitable for insulation contact. 7. If the fluorescent fixtures in the recreation room were to be mounted on the ceiling, what sort of marking would you look for on the label of the fixture? The ceiling is low-density cellulose fibreboard. Suitable for surface mounting. 8. What is the current draw of the recessed fixtures above the bar? Four fixtures at 60 watts each: 60 x 4 = 240 watts I = P/E = 240/120 = 2.0 amperes 9. Calculate the total current draw for Circuits B10, B12, and B14. Based on the estimated load for: B10 240 VA / 120 = 2A B12 1140 VA / 120 = 9.5A B14 966 VA / 120 = 8.05A

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Electrical Wiring: Residential, Seventh Canadian Edition

10. Complete the wiring diagram for the recreation room. Follow the suggested cable layout in Fig 19-2. Use coloured pencils or pens to identify the various colours of the conductor insulation.

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11. a. May a fluorescent fixture that is marked “Recessed fluorescent fixture” be installed in a suspended ceiling? Yes. b. May a fluorescent fixture that is marked “Suspended ceiling fluorescent fixture” be installed in a recessed cavity of a ceiling? No. The fixture must be approved for the location that it is being installed in. c. What CEC, Part I, section covers the installation of recessed fixtures? Rules 30-900 to 30-912. 12. Using Table D3 in Appendix D, calculate the maximum distance for a #12/2 NMD90 wire carrying 10 amperes at 240 volts if a 3% voltage drop is on the cable. Answer in metres. Show calculations. Table D2 dist. x % v.d. x D.C.F. x volts/120 = Max. distance. 9.8 m x 3 x 1.06 x 240 = 62.33 m maximum. 120 The Table D3 distance is obtained from the 10-ampere line and the No. 12 column = 9.8 m. The maximum % voltage drop is 3%. The wire is 90°C wire at 50% load; therefore, from the table in note 3 of Table D3 the distance correction factor is 1.06. 13. Using the plans provided with this textbook, complete a device and wiring layout for the recreation room area to minimum CEC standards. Because there are many possible layouts that meet the minimum requirements of the CEC, each answer must be independently evaluated.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 20 Branch Circuits for Workshop and Utility Area Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. WORKSHOP 1. a. What circuit supplies the workshop lighting? A17 b. What circuit supplies the plug-in strip over the workbench? A19 c. What circuit supplies the freezer receptacle? A12 2. What types of lighting fixtures are installed on the workshop ceiling? Four lampholders (two keyless) that mount directly to the outlet boxes, plus the fluorescent fixtures above the workbench. 3. Does a receptacle for a freezer have to be GFCI-protected? Explain. No. The same reasoning as for the smoke detectors applies. A slight “leakage” could cause the GFCI to trip to the off position, resulting in spoiled food. 4. Does a receptacle for a sump pump have to be GFCI-protected? Explain. No. This is a good example of a “dedicated receptacle,” which should be on a dedicated circuit for the sump pump. If connected to a GFCI-protected circuit, the receptacle or breaker could trip and the basement could be flooded. 5. When a 120-volt receptacle is provided for the laundry equipment in a basement, what is the minimum number of additional receptacle outlets required? What is the CEC reference? The CEC, Part I, requires one duplex receptacle in the space intended to accommodate a washing machine. It also requires at least one in a utility room or area and one in an unfinished basement area, and an additional one in a laundry room. Rule 26-710(e)(i). 6. When a single receptacle is installed on an individual branch circuit, the receptacle must have a rating not less than the rating of the branch circuit. The voltage and current must correspond to the rating of the configuration of the receptacle. Rule 26-722(f). 7. Calculate the total current draw of Circuit A17 if all lighting fixtures and the exhaust fan were turned on. I = VA/E = 656 = 5.47 amperes 120 8. If a #10 NMD90 cable is located in an ambient temperature of 42°C, what would be the temperature correction factor? From Table 5A in the 90°C column at 45°C ambient temperature, the correction factor is 0.87.

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9. What size of box would you use where Circuit A17 enters the junction box on the ceiling? This box has six #14 AWG conductors. A 4” x 1 ½” octagon box would be suitable. 10. The following is a layout of the lighting circuits for the workshop. Using the conduit layout in Figure 20-1, make a complete wiring diagram. Use coloured pencils or pens to indicate conductors.

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Electrical Wiring: Residential, Seventh Canadian Edition

WATER PUMP CIRCUIT

B

1. How is the motor disconnected if pumping is no longer required? By the double-pole breaker in Panel A and the disconnect switch next to the pump controller location. Normal start-stop operations are controlled by the pressure switch. 2. Why is a 240-volt motor preferable to a 120-volt motor for use in this residence? A 240-volt motor operates using one-half the current used by a 120-volt motor. Lower current results in lower line loss. 3. How many amperes does a 1-hp, 240-volt, single-phase motor draw? (See Table 45.) 8 amperes 4. What size are the conductors used for this circuit? Copyright © 2016 by Nelson Education Ltd.

20-3

#12 AWG conductors to be used for the pump circuit. Special-purpose outlets, see Table A-1. 5. a. What is the branch-circuit protective device? Circuit A5,7 is a 20-ampere double-pole overcurrent device in Panel A. b. What furnishes the running protection for the pump motor? A double-pole thermal overload switch mounted next to the pump. For submersible pumps, the controller contains the overload protection. Back-up overload protection is accomplished by installing Fusetron dual-element fuses in the disconnect switch. c. What is the maximum ampere setting required for running protection of the 1-hp, 240volt pump motor? 10 amperes = (8 x 1.25). Rule 26-106(1). 6. [Circle correct answer.] Submersible water pumps operate the electrical motor and actual pump located a. above the permanent water level. b. below the permanent water level. c. half above and half below permanent water level. 7. Because the controller contains the motor starting relay and the running and starting capacitors, the motor itself contains no moving parts, i.e., relays or switches for capacitors. 8. What type of pump moves the water inside the deep-well pipe? Centrifugal pump. 9. Proper pressure of the submersible pump system is maintained by a pressure switch. 10. Fill in the data for a 16-ampere electric motor, single-phase, 1.15 service factor. a. Branch-circuit protection, nontime-delay fuses. Normal size: 48 (use 45) A Switch size: 60 A (Table 29) Maximum size: 64 (use 60) A Switch size: 60 A (400%) Rule 28-200(a,e), D16 Chart.

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Electrical Wiring: Residential, Seventh Canadian Edition

b. Branch-circuit protection, dual-element, time-delay fuses. Normal size: 28 (use 25) A Switch size: 30 A (Table 29) Maximum size: 36 (use 35) A Switch size: 60 A (225%) Rule 28-200(a,e), D16 Chart. c. Branch-circuit protection, instant-trip breaker. Maximum setting 208 A (13 x) (Rule 28-210(b)) d. Branch-circuit protection—inverse time breaker. Maximum setting 40 A (Table 29, D16 Chart) e. Branch-circuit conductor size. #14 AWG Ampacity 20 A 125% of FLA = 16 x 1.25= 20 A f. Motor running protection using dual-element time-delay fuses. Maximum size 20 A (Rules 28-302(2) and 28-306) 11. The CEC is very specific in its requirement that submersible electric water pump motors be grounded. Where is this specific requirement found? Rule 26-954(d). 12. Does the CEC allow submersible pump cable to be buried directly in the ground? Yes, if the cable supplied with a submersible is also approved for direct earth burial. For example, RWU75, RWU90, TWU, and TWU75. Rule 26-954.

WATER HEATER CIRCUIT

C

1. At what temperature is the water in a residential heater usually maintained? 60°C to 72°C. 2. Magnesium rods are installed inside the water tank to reduce corrosion. 3. Is a separate meter required to record the amount of energy used to heat the water? No. 4. What is meant by the phrase “flat rate” installation? The utility will want to control the power demands of its users. One way is to turn “off” the energy supply to heater loads during “peak” demand periods and reenergize during light load demand periods. The utility charges the customers with this service a “flat rate” for the equipment and energy used. 5. What is the most common method of metering water heater loads? With the water heater connected to the regular house meter and feeding the water heater directly from the panel.

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6. Two thermostats are generally used in an electric water heater. a. What is the location of each thermostat? Approximately three-quarters of the way up from the bottom of the tank and onequarter of the way up from the bottom of the tank. b. What type of thermostat is used at each location? Upper—interlocking or snap-over type Lower—single-pole, on or off variety 7. a. How many heating elements are provided in the heater in the residence discussed in this text? Two. b. Are these heating elements allowed to operate at the same time? No. 8. When does the lower heater operate? When the water in the upper part of the tank reaches 65°C and the upper thermostat snaps over, allowing the lower element to operate. 9. The CEC states that water heaters must have a temperature regulating device set at 90°C maximum. Secondary protection is by a temperature cut out set at the factory at 96°C. Rule 26-750(1,2). 10. Why does the storage tank hold the heat so long? The insulation is designed to minimize heat loss. 11. The electric water heater is connected for “limited demand” so that only one heating element can be on at one time. a. What size of wire is used to connect the water heater? #12 AWG b. What size of overcurrent device is used? 20 amperes 12. a. If both elements of the water heater are energized at the same time, how much current will they draw? (Assume the elements are rated at 240 volts.) Element No. 1 = 3000 watts Element No. 2 = 2000 watts Add the total wattage of both elements: PT = P1 + P2 = 3000 +2000 = 5000 watts I = P/E = 5000/240 = 20.83 amperes b. What size of wire is required for the load of both elements? Show your calculations. #12 AWG wire, as per Table 2. 13. a. How much current do the elements in Question 12 draw if connected to 220 volts? Show your calculations. 240/220 = 20.83/x (ratio comparison) x = 220 x 20.83/240 x = 19.094 amperes

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Electrical Wiring: Residential, Seventh Canadian Edition

b. What is the wattage value at 220 volts? Show your calculations. P=ExI P = 220 x 10.094 P = 4201 watts 14. A 240-volt heater is rated at 1500 watts. a. What is its current rating at rated voltage? I = P/E = 1500/240 = 6.25 amperes b. What current draw would occur if connected to a 120-volt supply? 120 –240 = x/6.25 x = 120 x 6.26/240 x = 3.125 amperes c. What is the wattage output at 120 volts? R = E/I = 240/6.25 = 38.4 Ω P = E2/R = 1202/38.4 = 375 watts Note: 375 watts is one-quarter the 1500 watts at rated 240 volts. Therefore, one-half the rated volts = one-quarter the rated watts, or two times the rated volts = four times the rated watts. 15. A customer asks the electrician to set the water heater thermostat 30ºC below the maximum permitted by the CEC. The thermostat is set at a. 70°C. b. 66°C. c. 60ºC. d. 49 ºC.

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Instructor’s Solutions Manual to accompany

Prepared by Sandy F. Gerolimon Humber College

Instructor’s Solutions Manual to accompany Electrical Wiring: Residential, Seventh Canadian Edition By Mullin, Branch, Gerolimon, Trineer, Todd, Simmons Instructor Solutions Manual prepared by Sandy Gerolimon, Humber College Available on the SSO Instructor’s site at http://www.nelson.com/instructor COPYRIGHT © 2016 by Nelson Education Ltd. Nelson is a registered trademark used herein under licence. All rights reserved. For more information contact Nelson, 1120 Birchmount Road, Toronto, Ontario M1K 5G4. Or you can visit our Internet site at www.nelson.com ALL RIGHTS RESERVED. No part of this work covered by the copyright hereon may be reproduced or used in any form or by any means—graphic, electronic, or mechanical, including photocopying, recording, taping, web distribution or information storage and retrieval systems—without the written permission of the publisher.

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Table of Contents To the Instructor

v

Unit 1

General Information for Electrical Installations

1-1

Unit 2

Drawings and Specifications

2-1

Unit 3

Service Entrance Calculations

3-1

Unit 4

Service Entrance Equipment

4-1

Unit 5

Electrical Outlets

5-1

Unit 6

Determining the Number and Location of Lighting and Receptacle Branch Circuits

6-1

Conductor Sizes and Types, Wiring Methods, Wire Connections, Voltage Drop, Neutral Sizing for Services

7-1

Switch Control of Lighting Circuits, Receptacle Bonding, and Induction Heating Resulting from Unusual Switch Connections

8-1

Ground-Fault Circuit Interrupters, Arc Fault Circuit Interrupters, Transient Voltage Surge Suppressors, and Isolated Ground Receptacles

9-1

Unit 10

Lighting Fixtures and Ballasts

10-1

Unit 11

Branch Circuits for the Bedrooms, Study, and Halls

11-1

Unit 12

Branch Circuits for the Living Room and Front Entry

12-1

Unit 13

Branch Circuits for Bathrooms

13-1

Unit 14

Lighting Branch Circuit and Small Appliance Circuits for the Kitchen

14-1

Unit 15

Special Purpose Outlets for Ranges, Counter-Mounted Cooking Units Wall-Mounted Ovens , Food Waste Disposals , and Dishwashers

, 15-1

Unit 16

Branch Circuits for the Laundry, Washroom, and Attic

16-1

Unit 17

Electric Heating and Air Conditioning

17-1

Unit 7

Unit 8

Unit 9

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Unit 18

Oil and Gas Heating Systems

18-1

Unit 19

Recreation Room

19-1

Unit 20

Branch Circuits for Workshop and Utility Area

20-1

Unit 21

Heat and Smoke Detectors, Carbon Monoxide Detectors, and Security Systems

21-1

Unit 22

Swimming Pools, Spas, and Hot Tubs

22-1

Unit 23

Television, Telephone, Data, and Home Automation Systems

23-1

Unit 24

Lighting Branch Circuit for the Garage and Outdoor Lighting

24-2

Unit 25

Standby Power Systems

25-1

Unit 26

Residential Utility-Interactive Solar Photovoltaic Systems

26-1

Review Examination

R-1

Answers to the Review Examination

A-1

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To the Instructor The Seventh Canadian Edition of Electrical Wiring: Residential provides basic instructions for students, apprentices, and technicians. In order to assist the instructors it has been planned that each text unit can serve as its own lesson plan with review questions at the end of each chapter to summarize the material covered. The text units are sequenced to introduce the student to basic principles with progression to more advanced material. It is hoped that this will simplify the learning process. It is expected that the students will possess a reasonable level of mechanical aptitude skills and will also receive some supplemental instruction in blueprint reading for the building trades. The material emphasizes the 2015 Canadian Electrical Code (CEC), Part I, and all students should be encouraged to study the CEC in conjunction with their comprehensive study of Electrical Wiring: Residential. To assist the instructor, questions from the end of each unit have been included with answers/solutions. These may be used as additional review or examination questions. The diagrams have been checked and corrected from the previous edition to aid in the instructor facilitations of the program. We hope you enjoy this guide with Electrical Wiring: Residential and would appreciate suggestions for any improvements/additions that may be included in subsequent editions. Sandy Gerolimon can be reached at: [email protected].

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 1 General Information for Electrical Installations Solutions to Review Note: Where applicable, responses should be written in complete sentences. 1.

What is the difference between a code and a standard? a. Codes are standards that deal with life safety issues. b. Standards describe minimum performance levels.

2. What Code sets standards for the installation of electrical equipment? The Canadian Electrical Code, Part I, (CEC) is the basic standard, with local and provincial codes as standards that must also be considered. 3. What authority enforces the standards set by the CEC? The provincial or local electricity inspection authority. 4. Does the CEC provide minimum or maximum standards? The CEC standards are minimum standards but are expressed in both minimum and maximum terms. For example, Rule 2-308 is a minimum clearance of 1 m around electrical equipment, while Rule 8-104 is a maximum circuit loading. Both of these are minimum standards. 5. What do the letters CSA signify? Canadian Standards Association 6. Does compliance with the CEC always result in an electrical installation that is adequate, safe, and efficient? Why? Section O of the CEC states that “Compliance with the requirements of this Code and proper maintenance will ensure an essentially safe installation.” But if adequate provision is not made for future expansion, a hazardous condition could develop. 7. What are the general sections of the CEC? According to Table 1-1, the general sections of the CEC are Sections 0 to 16, and 26. 8. Is the section of the CEC that deals with wiring methods a general section or an amending section? General section. 9. When is an electrical installation required to be inspected? ALL work is required to be inspected. 10. What should you look for when trying to determine if a piece of electrical equipment is approved for use in Canada? CSA or other approval mark on the equipment.

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11. If a piece of electrical equipment is not approved for use in Canada, what should you do? Special inspection should be obtained for the equipment. 12. When the words “shall be” appear in a code reference, they mean that it (must) (may) (does not have to) be done. (Underline the correct answer.) must

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 2 Drawings and Specifications Solutions to Review

Note: For these exercises, refer to the blueprints provided with this textbook. Also, refer to the CEC when necessary. Where applicable, responses should be written in complete sentences. PART 1—DRAWING PLANS 1. Identify three line types shown on Sheet 2. Centre lines, border lines, hidden lines, dimension lines, visible lines 2. Determine the length of the lines for the following. SCALE

LENGTH

1:50

3m

1:75

4.5 m

1:100

6m

⅛″ = 1 ft

19 ft, or 5.71 m

¼″ = 1 ft

9 ft 6 in, or 2.9 m

3. What is the purpose of specifications? To supplement the plans by providing written information on materials and to the methods of construction. 4. In what additional way are the specifications particularly useful to the electrical contractor? They allow the contractor to prepare an accurate cost estimate without having to find all the data in the plans. 5. What is done to prevent a plan from becoming confusing because of too much detail? Symbols are used that refer to a table or notes. Information is supplied in the specifications. 6. Name three requirements contained in the specifications regarding material (Appendix A). a. Shall be all new b. Size and types specified c. Carry a label from an approved testing organization. 7. What are the two main hazards that the CEC is designed to prevent? a. Shock b. Fire

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8. What phrase is used when a substitution is permitted for a specific item in a specification? “or equivalent” 9. What is the purpose of an electrical symbol? To represent electrical equipment and components. 10. What is a notation? A note providing additional or more specific information. 11. List five electrical notations found on the plans for the residence used as an example in this textbook. Refer to the blueprints provided with this textbook. Found on the electrical drawing sheets. E6 is as follows:

PROVIDE TR, G.F.C.I. AND A.F.C.I. AS REQUIRED BY THE CANADIAN ELECTRICAL CODE

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Electrical Wiring: Residential, Seventh Canadian Edition

The following is found on the electrical drawing sheets. E5 is as follows:

PART 2—STRUCTURAL FEATURE 1. To what scale is the basement plan drawn? See plans. 1:50 2. What is the size of the footing for the steel support columns in the basement? 610 x 610 x 305 3. To what kind of material will the front porch lighting bracket fixture be attached? The fixture will be supported by fastening it to the electrical outlet box, which is set into the wood siding. 4. Give the size, spacing, and direction of the ceiling joists in the workshop. 50 x 255 @ 305 on centre, running front to rear. 5. What is the size of the lot on which this residence is located? 30 x 46 m 6. In what compass direction is the front of the house facing? 30 x 46 m

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7. How far is the front garage wall from the curb? 10.67 m 8. How far is the side garage wall from the property lot line? 9.145 m = 7620 (garage to set back) + 1525 (setback measurement) (shown on DWG #1 Site plan) 9. How many steel support columns are in the basement, and what size are they? 5 columns @ 76 mm outer diagram (shown on DWG #2 Basement) 10. What is the purpose of the I-beams that rest on top of the steel support columns? To support the floor joists. 11. Is the entire garage area to have a concrete floor? Yes. 12. Where is access to the attic provided? In the garage. 13. Give the thickness of the outer basement walls. 305 mm 14. What material is indicated for the foundation walls? Poured concrete. 15. Where are the smoke detectors located in the basement? One in the workshop near the entrance way; one at the foot of the basement stairs. 16. What is the ceiling height in the basement workshop from bottom of joists to floor? (DWG#4 Section A-A) 2690 - 255 = 2435 mm 17. Give the size and type of the front door. 813 x 2032 x 45 mm decorative with /light Sheet 7 under Door schedule 18. Who is to furnish the range hood? The electrical contractor. Appendix A, number 15. 19. Who is to install the range hood? The electrical contractor. Appendix A, number 19.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 3 Service Entrance Calculations Solutions to Review

Note: Refer to the CEC or to the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. When a service entrance calculation results in a value of 15 kW or more, what is the minimum size service required by the CEC? 100 amperes 2. a. What is the demand load per 90 m2 for the general lighting load of a residence? The first 90 m² has a demand of 5000 watts, and each 90 m² after has a demand of 1000 watts. Rule 8-200(1)(a)(i,ii) b. What are the demand factors for the baseboard heating load in dwellings? The first 10 kW at 100% and the remainder at 75% when automatic thermostatic control is provided in each room or area. Rule 62-118 (3)(a,b). 3. a. What is the ampere rating of the circuits that are provided for the lighting and power loads? The ampere rating is based on the lower value of the wire in the branch circuit or the fuse or circuit breaker protecting the circuit. Rule 8-104(1). In this residence, the rating is 15 amps. b. What is the maximum number of outlets permitted on a 15-ampere branch circuit by the CEC? 12 maximum. Rule 8-304(1). The maximum number of outlets may be exceeded if the load is not greater than 80% of the fuse or breaker. Rule 8-304(3). c. How many 15-ampere circuits are included in this residence? Main Panel A – 14 and Panel B – 14 (Sheet 7 of 8 Panel Schedule) 4. Why is the air-conditioning load for this residence omitted in the service calculations? What is the CEC rule number? Rule 8-106(4). Since a central air conditioning system in installed, it is electrically interlocked with the heating system such that only one of the two loads can operate at a time. 5. What demand factor may be applied to loads greater than 1500 watts, such as a clothes dryer and water heater, in addition to an electric range, Rule 8–200(1)(a)(vi). A demand of 25% is applied to the rating of the appliance. 6. What load may be used for an electric range rated at not over 12 kW? 6 kW. Rule 8-200(1)(a)(iv). 7. What is the load for an electric range rated at 16 kW, Rule 8–200(1)(a)(v)? Show calculations. 1st 12 kW = 6000 W Next 4 kW @ 40% = 1600 W Total = 7600 W

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8. What is the computed load when fixed electric heating is used in a residence? (Rule 62–116) If baseboard heating is used, then any amount over 10 kW may be reduced to 75%. If the heating is central forced air electric, the rating of the furnace applies at 100%. 9. On what basis is the neutral conductor of a service entrance determined? It is sized according to Rule 4-024(3) for the minimum size. This is based on the demand watts of the loads with a neutral (120 v or 120/240 v loads), divided by 240 volts for a 120/240-volt service. Most utilities require the neutral to be the same size as the line conductors except where there is an obvious large 240-volt load, as in the case of electric baseboard heating. 10. Why is it permissible to omit an electric space heater, water heater, and certain other 240-volt equipment when calculating the size of the neutral service entrance conductor for a residence? Because the equipment does not require a neutral or an identified conductor. 11. Calculate the minimum size of service entrance conductors required for a residence containing the following: floor area 8 m × 12 m; 12-kW electric range; 5-kW dryer 120/240-volt; 2200-watt sauna heater, 120-volt; 12 kW of baseboard heaters with individual thermostat control, 240-volts; two 3-kW, 240-volt air conditioners; 3-kW, 240-volt water heater. CALCULATIONS Area 96 m² Heating (12kW – 10kW@100% – 2kW@75%) Range Dry, Water Heater Sauna A/C* Total demand watts

6000 W 11500 W 6000 W 2000 W 2200 W 6000 W 33700 W

I = P/E 33.7 kW/240V = 140.42 amperes (L1, L2) & N * Rule 8-106(4) (not interlocked with heating) (L1, L2) Determine the sizes of the ungrounded conductors and the neutral conductor. Use type RW90 copper conductors. Two # 1/0 RW90 ungrounded conductors One # 1/0 RW90 neutral (or bare neutral if permitted) One # 6 AWG system grounding conductor to water meter (Rule 10-812(a))

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Electrical Wiring: Residential, Seventh Canadian Edition

STUDENT CALCULATIONS (Remember: MINIMUM Requirements) Minimum service ampacity Minimum switch Minimum fuse or circuit breaker Minimum bonding jumper 41 Minimum conduit size Minimum panel ampacity Minimum number of circuits in panel

140.42 amperes (Rule 8-104(1)) 200 amperes 150 amperes Table 13 (supplier you will get 200 amperes) #6 AWG Rule 10-614 (1)(a), Table 41 mm Table 6B 200 amperes 30 – of which ½ DP Rule 8-108(1)(c)

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 4 Service Entrance Equipment Solutions to Review

Note: Refer to the CEC or to the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Where does a consumer’s service start and end? A consumer’s service starts where the service drop conductors from the utility are attached and ends at the terminals in the service box, which is usually the main switch or circuit breaker. 2. What are supply service conductors? Conductors from the utility mains to the consumer service. 3. Who is responsible for determining the service location? The supply authority. Rule 6-408(f). 4. a. [Circle one.] The service head must be located (above) (below) the point where the supply service conductors are spliced to the consumer’s service conductors. b. What CEC rule provides the answer to part (a)? Rule 6-116(b). 5. a. What size and type of conductors are installed for this service? 3/0 AWG RW90 XLPE 600V without jacket. b. What size of conduit is installed? 53 mm, Table 6A. c. What size of grounding electrode conductor (system grounding conductor) is installed? (Not neutral) #6 AWG, Rule 10-812(a). d. Is the grounding electrode conductor insulated, armoured, or bare? Bare. 6. How and where is the grounding electrode conductor attached to the water pipe? The grounding electrode conductor is attached with a ground clamp to the water pipe where it enters the basement wall. 7. When a service mast is extended through a roof, must it be guyed? When the distance between the upper support clamp and the point of attachment is greater than 1.5 m, or if the supply service is greater than 30 m in length, then it should be guyed. Rule 6-112(4), Appendix B.

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8. What are the minimum distances or clearances for the following? a. Supply service conductors, clearance over private driveway 4 m, Rule 6-112(2)(b). b. Supply service conductors, clearance over private sidewalks 3.5 m, Rule 6-112(2)(d). c. Supply service conductors, clearance over alleys 5.5 m, Rule 6-112(2)(a). d. Supply service conductors, clearance over a roof having a roof pitch that may be walked on. (Voltage between conductors does not exceed 300 volts.) 2.5 m, Rule 12310. e. Supply service conductors, horizontal clearance from a porch 1 m, Rule 6-112(3). f. Supply service conductors, clearance from a window or door 1 m, Rule 6-112(3). 9. What size of ungrounded conductors is installed for each of the following residential services? (Use type RW90 XLPE copper conductors). a. 60-ampere service #6 RW90 XLPE copper. Use 75ᴼColumn. b. 100-ampere service #3 RW90 XLPE copper. Use 75ᴼColumn. c. 200-ampere service #3/0 RW90 XLPE copper. Use 75ᴼColumn. 10. What size of grounding electrode conductors are installed for the services listed in Question 9? (Rule 10–812) a. 60-ampere service #6 AWG grounding conductor (Rule 10–812(a)). b. 100-ampere service #6 AWG grounding conductor (Rule 10–812(a)). c. 200-ampere service #6 AWG grounding conductor (Rule 10–812(a)). 11. What is the recommended height of a meter socket from the ground? The local utility must always be contacted for the exact height measurement. Usually the height is 1.73 m measured to the centre of the meter socket above finished grade. The rule of thumb is eye level, but that depends on how tall you are and if the ground you are standing on is finished grade. 12. a. What is the minimum length of conductor that must be left extending out of the service head? 750 mm b. What CEC rule covers this? Rule 6-302. 13. What are the restrictions on the use of bare neutral conductors? a. Copper and run in raceway. b. Aluminum in aluminum or non-metallic raceway above ground. c. Part of busway or service entrance cable. d. Part of neutral supported cable used in accordance with Rule 6-302(2). 14. How far must mechanical protection be provided when underground service conductors are carried up a pole? Rigid conduit is to be used to provide mechanical protection where the wire is exposed to injury. This protection is to be within 600 mm (24”) of the utility connection point. Check with your local supply authority.

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15. What is the maximum number of consumer’s services allowed without special permission? Four. Quote the CEC rule. Rule 6-104. 16. Complete the following table by filling in the columns with the appropriate information. [Note to formatter: answers are in red; those cells of the table should be blank for studentfacing question] CIRCUIT NUMBER B 16

AMPERE RATING 15

A 19

15

1

120

14

A 5, 7

20

2

240

12

D. ATTIC EXHAUST FAN E. KITCHEN LIGHTING F. HYDROMASSAGE TUB G. ATTIC LIGHTING

A 10

15

1

120

14

B7

15

1

120

14

A9

15

1

120

14

B 20

15

1

120

14

H. COUNTERMOUNTED COOKING UNIT I. ELECTRIC FURNACE

B 2, 4

40

2

240

8

A 1, 3

70

2

240

4

A. LIVING ROOM RECEPTACLE OUTLETS B. WORKBENCH RECEPTACLE OUTLETS C. WATER PUMP

POLES VOLTS WIRE SIZE 1 120 14

17. a. What size of conductors supply Panel B? #3 RW90 XLPE 600 V unjacketed. b. What size of conduit? 27 mm, Table 6A. c. Is this raceway run in the form of EMT or rigid conduit? EMT. d. What size of overcurrent device protects the feeders to Panel B? 100A double pole. 18. How many electric meters are provided for this residence? One. 19. According to the CEC, is it permissible to ground rural service entrance systems and equipment to driven ground rods when a metallic water system is not available? Yes. Rule 10-700. 20. What CEC table lists the sizes of grounding electrode conductors to be used for service entrances of various sizes similar to the type found in the residence discussed in this text? Rule 10-812(a), #6 AWG copper.

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21. Do the following conductors require mechanical protection? a. # 8 grounding conductor Yes. Rule 10-806(3). b. # 6 grounding conductor No, unless rigidly stapled to the construction. Rule 10-806(2). c. # 4 grounding conductor No, unless rigidly stapled to the construction. Rule 10-806(2). 22. Why is bonding service entrance equipment necessary? Since the service-entrance conductors are not fused, a fault on one or more of the service conductors may result in high current attempting to flow to ground. Proper bonding provides a low-impedance path to ground, rather than passing the heavy flow of current through possibly loose locknuts, bushings, or eccentric and concentric knockouts, resulting in severe arcing and sparking. 23. What special types of bushings are required on service entrances when metallic raceways are used? Bonding or grounding bushings. 24. When #8 AWG conductors or larger are installed, what additional provision is required on the conduit ends? Insulation must be provided. Use insulating bushings with double locknuts, combination insulating and metal bushings, insulating sleeves (insuliner), or any other approved insulating means. Rule 12-906(2). 25. What minimum size copper bonding jumpers must be installed to properly bond the electric service for the residence discussed in this text? 200A Service #6 copper. Table 41 for size of bonding jumper. 26. a. What is a Type D fuse? A plug fuse that has time-delay characteristics. b. Where could a Type D fuse be installed? In circuits containing motor loads or cycling loads such as electric water heaters. 27. a. What is the maximum voltage permitted between conductors when using plug fuses? Not over 125 volts between conductors unless the circuit has a grounded neutral and operates at not more than 150 volts to ground. b. May plug fuses be installed in a switch that disconnects a 120/240-volt clothes dryer? Plug fuses shall not be used in circuits exceeding 125 volts between conductors except if the system has a grounded neutral where no conductor is more than 150 volts to ground. So, in this case, yes, you can.

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Electrical Wiring: Residential, Seventh Canadian Edition

c. Give a reason for the answer to (b). Since it’s a three-wire system that has the neutral in the system, the conductor voltage to ground between any conductor to ground does not exceed 150 volts, so you can. Rule 14-202 supports this answer. 28. What part of a circuit breaker causes the breaker to trip a. on an overload? Bimetallic element. b. on a short circuit? Magnetic coil. 29. List the standard sizes of circuit breakers up to and including 100 amperes. 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, and 100 amperes. 30. Using the method shown in this unit, what is the approximate short-circuit current available at the terminals of a 50-kVA single-phase transformer rated 120/240 volts? The transformer impedance is 1%. a. Line-to-line? I = 50 x 1000/240 = 208.33 amperes Multiplier equals 100/1 = 100 208.33 x 100 = 20833 amperes available, short-circuit current, line-to-line. b. Line-to-neutral? 20833 x 1.5 = 31250 amperes available, short-circuit current, line-to-neutral. 31. Where is the service for this residence located? On the east wall. 32. a. On what type of wall is Panel A fastened? Cement block. b. On what type of wall is Panel B fastened? Cement block. 33. When conduits pass through the wall from outside to inside, the conduit must be sealed to prevent air circulation through the conduit. 34. Briefly explain why electrical systems and equipment are grounded. Electrical systems are grounded to minimize the line surges and stabilize the normal voltage to ground. Equipment is grounded to minimize the voltage to ground on that equipment. 35. What CEC rule states that all overcurrent devices must have adequate interrupting ratings for the current to be interrupted? Rule 14-012. 36. All electrical components have some sort of “withstand rating,” which indicates the ability of the component to withstand fault currents for the time required by the overcurrent device to open the circuit. What CEC rule refers to withstand ratings with reference to fault current protection? Rule 14-012(a), Appendix B.

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37. Arcing fault damage is closely related to the value of ampere-squared-seconds (I ² T). 38. In general, systems are grounded so that the maximum voltage to ground does not exceed [circle one] a. 120 volts. b. 150 volts. c. 300 volts. 39. An electric clothes dryer is rated at 5700 watts. The electric rate is 10.091 cents per kWh. The dryer is used continuously for three hours. Find the cost of operation, assuming that the heating element is on continuously. Cost = 5700 x 3 x 0.10091/1000 = 1.726 ($1.73) 40. Rule 14–012 requires that the service equipment (breakers, fuses, and the panel itself) be rated [circle one] a. equal to or greater than the current it must interrupt. b. equal to or greater than the available voltage and the fault current that is available at the terminals. 41. Read the meter below. Last month’s reading was 22 796. How many kilowatt-hours of electricity were used for the current month?

The meter shows the following dial setting: 23 079. 23 079 – 22 796. This leaves a difference of 283. So this would be represented as: .283 kWh.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 5 Electrical Outlets Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What does a plan show about electrical outlets? It shows, in a simple manner, the location and type of outlet, switch, or special electrical device needed. 2. What is an outlet? A point on the wiring system at which current is taken to supply utilization equipment. 3. Match the following switch types with the proper symbol. a. single-pole Sp b. three-way S4 c. four-way S d. single-pole with pilot light S3 4. The plans show curved lines running between switches and various outlets. What do these curved lines indicate? The outlets that are controlled by the switches. 5. Why are the lines mentioned in Question 4 usually curved? To distinguish them from visible lines. 6. a. What are junction boxes used for? For joining two or more cables or conduits. b. Are junction boxes normally used in wiring the first floor? No. The CEC, Part I, requires that they be installed so that the cover openings are accessible. Note: The requirements for accessibility would mar the appearance of the living quarters; therefore, connections are usually made in outlet boxes. c. Are junction boxes normally used to wire exposed portions of the basement? Yes. The installation will not spoil the appearance of the basement. 7. How are standard sectional switch (device) boxes mounted? The boxes can be nailed or screwed to a structural member or wood backing or mounted to brackets or metal mounting strips or adjustable bar hangers.

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8. a. What is an offset bar hanger? An offset bar hanger is a device on which boxes are fastened so they can be mounted between joists or studs. The hangers are available in adjustable types for different joist spacing. b. What types of boxes may be used with offset bar hangers? Practically any outlet or switch box with a ½ -inch knockout can be used with offset bar hangers. 9. What methods may be used to mount lighting fixtures to an outlet box fastened to an offset bar hanger? Either a fixture stud or the No. 8-32 screw holes in the box can be used. Fixtures are usually furnished with some means to fasten the fixture to the box using either one or both of these methods. Section 30-302(3). 10. What is the size of the opening of a switch (device) box for a single device? 3” x 2”. Single sectional box sizes are found in Table 23. 11. The space between a door casing and a window casing is 89 mm. Two switches are to be installed at this location. What problems could you encounter when placing the switches in this location? What would you recommend as a possible solution? The space is too small for a two-gang face plate; therefore, the switches must be mounted one above the other vertically or one of them relocated to another location. 12. Three switches are mounted in a three-gang switch (device) box. The wall plate for this assembly is called a three-gang, three-hole switch plate. 13. [Circle the correct answer.] For each fixture stud inside a box, (increase) (decrease) the number of conductors allowed by one. 14. a. How high above the finished floor are the switches located in the garage of this dwelling? 1200 mm to centre. b. In the living room of this dwelling? 1300 mm to centre. 15. How high above the finished floor are the receptacle outlets in the garage located? 1200 mm In the living room? 300 mm 16. Outdoor receptacle outlets in this dwelling are located 450 mm above grade.

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17. In the spaces provided, draw the correct symbol for each of these items: a. Lighting panel

or LP

b. Clock outlet

LP

c. Duplex outlet d. Outside line telephone e. Single-pole switch

or

f. Four-way switch

or

g. Duplex outlet, split-circuit

Drawing symbol

h. Lampholder with pull switch i. Weatherproof outlet j. Special-purpose outlet k. Fan outlet l. Range outlet m. Power panel

LP

n. Three-way switch

or

o. Pushbutton p. Thermostat q. Electric door opener

G

r. Multioutlet assembly

18. The front edge of a box installed in a combustible wall must be flush with the finished surface. Rule number? Rule 12-3016(1).

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19. List the maximum number of #12 AWG conductors permitted in a a. 4 × 1½-in. (102 × 38-mm) octagon box. 8 Table 23 b. 411/16 × 1½-in. (119 × 38-mm) square box. 17 Table 23 c. 3 × 2 × 2½-in. (76 × 51 × 64-mm) device box. 7 Table 23 20. Hanging a ceiling fixture directly from a plastic outlet box is permitted only if the carton or box is marked that the non-metallic box is CSA approved for that purpose. 21. It is necessary to count fixture wires when counting the permitted number of conductors in a box according to Rule 12–3034(1)(d). [Underline or circle the correct answer.] (True) (False) 22. CEC Table 23 allows a maximum of ten wires in a certain box. However, the box will have two wire connectors and one fixture stud in it. What is the maximum number of wires allowed in this box? 10 – 1 for two wire connectors = 9 9 – 1 for fixture stud = 8 wires maximum 23. When laying out a job, the electrician will usually make a layout of the circuit, taking into consideration the best way to run the cables and/or conduits and how to make up the electrical connections. Doing this ahead of time, the electrician determines exactly how many conductors will be fed into each box. With experience, the electrician will probably select two or three sizes and types of boxes that will provide adequate space to meet Code requirements. CEC Table 23 shows the maximum number of conductors permitted in a given size box. However, the number of conductors shown in the table must be reduced by 1 conductor(s) for two wire connectors by 1 conductor(s) for the fixture stud by 2 conductor(s) for each wiring device mounted on a single strap by 0 conductor(s) for one or more bare copper bonding conductors. Rule 12-3034(1,2) 24. Define the term bonding. Why is the installation of bonding conductors important? Bonding is a low impedance path obtained by permanently connecting all noncurrent-carrying metal parts to assure electrical continuity and having sufficient capacity to conduct safely any current likely to be imposed on it. Bonding ensures that all of the non-current-carrying metal parts of the electrical system are at the same potential.

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Unit 6 Determining the Number and Location of Lighting and Receptacle Branch Circuits Solutions to Review

1. A living room wall is 6 m long. How many receptacles are required for the wall? Two. 2. A hallway is 3 m long and has a doorway fitted at each end. Does this hallway require a receptacle? Yes. 3. A hallway is 6 m long and has an open doorway at each end. The hall opens onto two rooms that each has one receptacle within 1 m of the doorway. Does this hallway require a receptacle? No. No point in the hall is more than 4.5 m from a receptacle. 4. How many receptacles are required in an unfinished basement with an area of 63 m2? One. 5. A kitchen counter is 3 m long. A sink that is 600 mm is located in the exact centre of the counter. How many receptacles are required for the counter? Two. 6. How many of the receptacles in Question 5 require GFCI protection? Two. 7. A counter has an isolated work surface of 600 mm between a sink and a built-in oven. Is a receptacle required in this space? Yes. 8. How many luminaires or lampholders are required for an unfinished basement area that is 63 m2? Three, one for every 30 m2 or fraction thereof. 9. How many receptacles are required in an attached two-car garage? Two, one for each car space. 10. How many luminaries are required in an attached two- car garage? One. 11. When is a luminaire required for a stairway? All stairways are required to be lighted.

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12. When is switch control required at the top and bottom of a stairway? When there are four or more risers. Exception is single-dwelling unfinished basement with no exits. 13. When a stairway leads to an unfinished basement that has an outside exit, is a switch required at the top and bottom of the stairs? Yes. 14. When should a receptacle be provided for a central vacuum unit? When the ducting for the central vac is installed. 15. A receptacle in a utility room is supplied from its own circuit. Can the wiring from the receptacle be extended to supply eight outlets in a finished family room? No. A separate circuit is required for the utility room. 16. Why shouldn’t a freezer be placed on a circuit protected by a GFCI? Nuisance tripping of the GFCI will cause the freezer to lose power. 17. What outlets in a dwelling unit must have AFCI protection? All receptacles except bathrooms with basin, refrigerator, kitchen counter receptacles, kitchen island receptacle, peninsula, sump pumps of dwelling units. 18. A counter has three 5-20A receptacles. What is the minimum number of branch circuits that may be used for these receptacles? Two. 19. What is the minimum number of circuits that may be run to a laundry room? Minimum of one for the laundry room receptacles, one for the lighting, additional if electric dryer is supplied. 20. Does the receptacle located next to a washbasin in a bathroom have to be on its own circuit? No. This is not a requirement of the CEC.

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Unit 7 Conductor Sizes and Types, Wiring Methods, Wire Connections, Voltage Drop, Neutral Sizing for Services Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What is the largest size of solid wire that is commonly used for branch circuits and feeders? #10 AWG 2. What is the minimum size of branch-circuit conductor that may be installed in a dwelling unit? #14 AWG copper 3. What exceptions, if any, are there to the answer for Question 2? Wires used in lighting fixtures, bell wiring, and remote-control low-energy circuits. Section 16 and Table 12. 4. Define the term ampacity. The current carrying capacity of a wire expressed in amps. 5. What is the maximum voltage rating of all NMSC? 300 volts for non-metallic sheathed cable 6. Indicate the ampacity of these Type T90 Nylon (copper) conductors. Refer to Table 2. a. 14 AWG 25 amperes b. 12 AWG 30 amperes c. 10 AWG 40 amperes d. 8 AWG 55 amperes e. 6 AWG 75 amperes f. 4 AWG 95 amperes 7. What is the maximum operating temperature of these conductors? Give the answer in Celsius. (Use Tables 11 and 19.) a. Type TEW 60°C (Table 11, note 3) b. Type R90 90°C c. Type LVT 60°C d. Type DRT 60°C 8. What are the colours of the conductors in non-metallic-sheathed cable for a. two-wire cable? black, white, bare b. three-wire cable? red, black, white, bare

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9. For non-metallic-sheathed (Type NMD90) cable, can the uninsulated conductor be used for purposes other than bonding? No. 10. Under what condition may non-metallic-sheathed cable (Type NMD90) be fished in the hollow voids of stud walls? Where it is run as concealed wiring and not subject to excessive moisture. 11. a. What is the maximum distance permitted between straps on a cable installation? 1.5 m b. What is the maximum distance permitted between a box and the first strap in a cable installation? 300 mm 12. What is the difference between Type AC90 and Type TECK90 cable? TECK90 can be used in a wet location, while AC90 cannot. TECK90 also has a tighter spiral. Table 19. 13. [Fill in the blank and then circle the correct answer.] Type AC90 cable may be bent to a radius of not less than six times the diameter of the cable, measured to the (inside, outside) edge of the cable. 14. When armoured cable is used, what protection is provided at the cable ends? Anti-short bushings or other acceptable bushings of insulating material. Rule 12-610 (1)(a). 15. What protection must be provided when installing a cable in a notched stud or joist? The cable must be protected by a metal plate at least 1.59 mm thick (1/16 in). Rule 12-516(1)(a) and Appendix G. 16. Cables passing through a stud where the edge of the bored hole is less than 32 mm from the edge of the stud require additional protection. 17. a. Is non-metallic-sheathed cable permitted in your area for residential occupancies? Refer to local code and inspection department. b. From what source is this information obtained? The local regulatory authority. 18. [Circle the correct answer.] Is it permitted to use flexible metal conduit over 2 m long as a bonding means? (Yes) (No) 19. [Circle the correct answer.] Liquidtight flexible metal conduit (may) (may not) serve as a bonding means.

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Electrical Wiring: Residential, Seventh Canadian Edition

20. The allowable current-carrying capacity (ampacity) of aluminum wire is less than that of an equivalent copper wire. Use Rule 4-002 and Tables 2, 4, and 13 to complete the following table. Enter both ampacity and maximum overcurrent protection values.

WIRE #12 R90 #10 R90 #3 TW75 0000 TW 500 kcmil RW75

COPPER Ampacity Overcurrent Protection 30 30 40 40 100 100 230 250 380 400

ALUMINUM Ampacity Overcurrent Protection 35 35 45 45 115 125 280 300 485 500

21. [Circle the correct answer.] All solderless wire connectors are approved to connect aluminum and copper conductors together in the same connector. (True) (False) 22. Terminals of switches and receptacles marked CO/ALR are suitable for use with copper, aluminum, and copper-clad aluminum conductors. 23. When non-metallic-sheathed cables are bunched or bundled together for distances longer than 600 mm, what happens to their current-carrying ability? Their ampacity must be derated according to Table 5C. 24. A 120-volt branch circuit supplies a resistive heating load of 10 amperes. The distance from the panel to the heater is about 43 metres. Calculate the voltage drop using (a) #14, (b) #12, (c) #10, and (d) #8 AWG copper conductors. a. Ud = K I x L x 2/CMA = (39.4 x 10 x 43 x 2)/4110 = 8.24 volts b. Ud = K I x L x 2/CMA = (39.4 x 10 x 43 x 2)/6530 = 5.19 volts c. Ud = K I x L x 2/CMA = (39.4 x 10 x 43 x 2)/10380 = 3.26 volts d. Ud = K I x L x 2/CMA = (39.4 x 10 x 43 x 2)/16510 = 2.05 volts 25. In Question 24, it is desired to keep the voltage drop to 3% maximum. What is the minimum size wire that would be installed to accomplish this 3% maximum voltage drop? 3% of 120 volts is 3.6 volts. Therefore, the #10 AWG conductor or larger would be correct. Note to instructor: If time permits, you could ask the student to do a few calculations of the wattage output of the 10-amperes heater at the different voltages resulting from using different wire sizes.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 8 Switch Control of Lighting Circuits, Receptacle Bonding, and Induction Heating Resulting from Unusual Switch Connections Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. The identified grounded circuit conductor may be which colour? [Circle one.] State the CEC rule that specifies this. a. green b. white c. yellow d. grey e. green with yellow stripes Rule 4-030(1). 2. A T-rated switch may be used to its rated current capacity when controlling an incandescent lighting load. Rule 14-508(b) 3. What switch type and rating are required to control five 300-watt tungsten filament lamps on a 120-volt circuit? Show calculations. PT = 5 * 300 = 1500 W, So I = P/E = 1500/120 = 12.5A This circuit will need a Category 2 general purpose switch. 4. To control a lighting load from one control point, what type of switch would you use? Single-pole switch. 5. Single-pole switches are always connected to the ungrounded (HOT) wire. 6. Complete the connections in the following arrangement so that both ceiling light outlets are controlled from the single-pole switch. Assume the installation is in cable.

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7. a. Complete the connections for the diagram. Installation is cable.

b. Which conductor of the cable feeds the switch? c. Which conductor is used as the return wire? d. From which wire does the switch feed tap? e. What are the colours of the conductors connected to the fixture?

White Black Black Black and white

8. What type of switch is installed to control a lighting fixture from two control points? How many switches are needed? Three-way switches are required. Two three-way switches are needed.

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Electrical Wiring: Residential, Seventh Canadian Edition

9. Complete the connections in the following diagram so that the lamp may be controlled from either three-way switch.

Option #1

Option #2

10. Show the connections for a ceiling outlet to be controlled from any one of three switch locations. The 120-volt feed is at the light, Rule 4–036(2). Label the conductor colours. Assume the installation is in cable.

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2- conductor cable

3- conductor cable

11. Match the following switch types with the correct number of terminals for each. Three-way switch Two terminals Single-pole switch Four terminals Four-way switch Three terminals 12. When connecting single-pole, three-way, and four-way switches, they must be wired so that all switching is done in the ungrounded (HOT) circuit conductor. 13. If you had to install an underground three-wire feeder to a remote building using three individual conductors, which of the following installations “meets code”? [Circle correct installation.]

14. Is it always necessary to attach the bare equipment bonding conductor of a non-metallicsheathed cable to the green hexagonal bonding screw on a receptacle? Explain. Yes. The receptacle is fitted with the ground screw so that the bare copper bonding wire will be connected to the box first, then to the receptacle. This will ensure that if the receptacle is removed, the system is still bonded to ground. Rule 10-808(2).

15. When two non-metallic-sheathed cables enter a box, is it permitted to bring both bare bonding conductors directly to the bonding terminal of a receptacle, using the terminal as a splice point? No. A terminal may not have more than one wire connected to it, unless identified for such use.

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Unit 9 Ground-Fault Circuit Interrupters, Arc-Fault Circuit Interrupters, Transient Voltage Surge Suppressors, and Isolated Ground Receptacles Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Explain the operation of a GFCI. Why are GFCI devices used? Where are GFCI receptacles required? A ground-fault circuit interrupter (GFCI) senses an unbalanced current flow. An unbalanced current occurs when a ground fault exists. In other words, some of the current flow in a circuit is going to a grounded object from the hot conductor. This current flow may result in injury or death if it passes through a human being. The GFCI device interrupts the flow of current if an unbalanced current exists. A GFCI device may be an integral part of the branch-circuit breaker or part of the receptacle. Ground-fault protection supplied as part of the main service or a feeder is normally installed to protect electrical equipment against arcing ground faults. A ground-fault circuit interrupter is required where there is a possibility that a person will be operating electrical equipment, such as a drill, saw, electrical lawn mower or hair dryer, from a particular outlet. For example, this outlet could supply a swimming pool or receptacles outside the house or in a bathroom. 2. Residential GFCI devices are set to trip a ground-fault current of 6mA. 3. What are the residential applications of GFCI receptacles? GFCI-protected receptacles are required for all receptacles within 1.5 m of a sink, outside, and may also be used to replace two-wire duplex receptacles in renovation applications. Rules 26-700 (8,11), 26-710(n). 4. The CEC requires GFCI protection for certain receptacles in the bathroom. Explain where these are required. Any receptacle located within 1.5 m of a sink, bathtub, or shower stall must be GFCI protected. Rule 26-700(11).

5. Is it a CEC requirement to install GFCI receptacles in a fully carpeted, finished recreation room in the basement? Circle one. (Yes) (No) 6. A homeowner calls in an electrical contractor to install a separate circuit in an unfinished basement for a freezer. Is a GFCI receptacle required? No.

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7. GFCI protection is available as (a) a branch-circuit breaker GFCI, (b) a feeder-circuit breaker GFCI, (c) an individual GFCI receptacle, (d) a feedthrough GFCI receptacle. What type would you install for residential use? Explain your choice. (c) an individual GFCI receptacle, (d) a feedthrough GFCI receptacle. They have the lowest cost. 8. Extremely long circuit runs connected to a GFCI branch-circuit breaker might result in [circle the letter of the correct answer] a. nuisance-tripping of the GFCI. b. loss of protection. c. the need to reduce the load on the circuit. 9. If a person comes into contact with the hot and grounded circuit conductors of a two-wire branch circuit that is protected by a GFCI, will the GFCI trip? Why or why not? No. A GFCI trips only when there is a line-to-ground fault. It should be emphasized that GFCIs do not provide short-circuit protection. 10. What might happen if the line and load connections of a GFCI receptacle are reversed? The actual tripping mechanism is on the load side of the line supply terminals. If the 120-volt circuit were to be connected to the load terminals, should a ground-fault occur on the downstream device, the GFCI would trip off. All downstream devices would be de-energized, but the GFCI itself would still be energized. If the fault occurred at the GFCI receptacle, it would not trip off. 11. May a GFCI receptacle be installed on a replacement in an old installation where the twowire circuit has no bonding conductor? Circle one. (Yes) (No) 12. What two types of receptacles may be used to replace a defective receptacle in an older home with knob-and-tube wiring where a bonding means does not exist in the box? A GFCI receptacle or a grounding receptacle protected by a Class A GFCI or effectively bonded to ground. Rule 26-700 (7,8). 13. You are asked to replace a receptacle. Upon checking the wiring, you find that the wiring method is conduit and that the wall box is properly bonded. The receptacle is of the older style two-wire type that does not have a bonding terminal. You remove the old receptacle and replace it with [circle the letter of the correct answer] a. the same type of receptacle as the type being removed. b. a receptacle of the bonding type. c. a GFCI receptacle. 14. What colour are the terminals of a standard bonding-type receptacle? The “HOT” terminal is brass colour; the grounded circuit conductor terminal is white or silver; the bonding terminal is green. 15. What special shape are the bonding terminals of receptacle outlets and other devices? The bonding terminal is hexagon-shaped (six sides).

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16. Why are GFCI receptacles installed on construction sites? Some of the hazards that may be encountered on a construction site are shock hazard from temporary wiring; workers standing in water; working in close proximity to or in contact with steel framing; electric cords and cables subject to severe mechanical abuse. 17. In your own words, explain why the CEC does not require receptacle outlets in garages and basements to be GFCI-protected. Nuisance-tripping. Where there are cord-connected appliances such as freezers, garage door openers, and refrigerators, the normal or slightly above-normal leakage currents might nuisance-trip the GFCI. 18. What do the letters TVSS stand for? transient voltage surge suppression 19. Transients (surges) on a line can cause spikes or surges of energy that can damage delicate electronic components. A TVSS device contains one or more metal-oxide varistors that bypass and absorb the energy of the transient. 20. Undesirable noise on a circuit can cause computers to lock up or lose their memory, and/or can cause erratic performance of the computer. This noise does not damage the equipment. The two types of this noise are EMI and RFI. What do these letters mean? EMI means electro-magnetic interference RFI means radio frequency interference 21. Can TVSS receptacles be installed in standard device boxes? Yes. 22. When an isolated ground receptacle is installed, the CEC permits the separate equipmentbonding conductor to be carried back through the raceway or cable to the distribution panel. What section of the CEC references this topic? Rule 10-904(8) 23. Briefly explain the difference between a GFCI breaker and an AFCI breaker. A GFCI breaker monitors the current in line and identifies conductors. If the difference exceeds 6 mA, the breaker de-energizes the circuit. An AFCI breaker monitors the voltage and current signatures associated with arcing faults. If an arcing fault is detected, the breaker de-energizes the circuit.

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Unit 10 Lighting Fixtures and Ballasts Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Is it permissible to install a recessed fixture directly against wood ceiling joists? Explain why or why not. No, due to the heat over time this will dry out the wood and lead to combustion. 2. If a recessed fixture without an approved junction box is installed, what extra wiring must be provided? The fixture must be wired with conductors having temperature ratings suitable for the temperature at the fixture. These conductors must be installed in a raceway at least 450 mm long but not more than 2 m long. A junction box must be provided at least 300 mm from the fixture. Rule 30-910. 3. Recessed fixtures are available for installation in direct contact with thermal insulation. These fixtures bear the CSA mark “Type IC.” 4. Unless specially designed, all recessed incandescent fixtures must be provided with factory-installed thermal protection. 5. Plans require the installation of a surface-mounted fluorescent fixture on the ceiling of a recreation room that is finished with low-density ceiling fibreboard. What sort of mark would you look for on the label of the fixture? CSA or other acceptable approval logo and have a maximum temperature rating of 90ᴼC. 6. If a recessed fixture bears no marking that it is listed for branch-circuit feedthrough wiring, is it permitted to run the circuit conductors from fixture to fixture? What section of the CEC covers this? No, it is not permitted to run branch feedthrough wiring. Section # 30-910(8). 7. Fluorescent ballasts for all indoor applications must be Class P type. These ballasts contain internal thermal protection to protect against overheating.

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8. You are called on to install a number of lighting fixtures in a suspended ceiling. The ceiling will be dropped about 200 mm from the ceiling joists. Briefly explain how you might go about wiring these fixtures. The branch-circuit wiring is installed above the suspended ceiling using standard wiring methods, such as EMT, NMSC, or AC90 cable. This depends upon the local electrical codes. Outlet boxes are installed above the ceiling, usually on the bottom or sides of the ceiling joists. The boxes are located near the location of the suspended ceiling “lay in” fixtures. From the outlet boxes, NMSC, armoured cable, or flexible metal conduit as applicable can be run to the knockouts on the fixture. These flexible connections are not to exceed 2 m. In the case of the NMSC and armoured cable, a staple or strap must be installed within 300 mm or the outlet box. It is recommended that the same be done for the flexible metal conduit. The conductor temperature rating must be suitable for the temperature requirements as stated on the fixture label. The fixtures are hoisted up and positioned so as to lay in the “T” bars of the ceiling grid. The fixtures must be securely fastened to the suspended ceiling grid. The fixtures must be securely fastened to the suspended ceiling metal framing members with clips, screws, or bolts. It is also a requirement in most localities that the fixture have an independent means of support other than the ceiling; this is usually jack chain and “S” hooks, which will support the fixture so that in the event of a fire, earthquake, or ceiling collapse from a similar problem, the fixture will not fall down onto someone’s head. If the fixtures have an internal connection box, such as in the case of many potlights, cable and /or conduit may be connected directly to the fixture. The outlet boxes indicated above may be eliminated in this case. 9. The CEC places a maximum open circuit voltage on lighting equipment in homes. [Circle the correct answer.] The maximum voltage is (300) (600) (750) (1000). Where in the CEC is this voltage maximum referenced? 150 volts-to-ground. Rules 2-106, 30-102. 1000 volts. Rule 30-802 gives this specific reference to electric discharge lighting.

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Unit 11 Branch Circuits for the Bedrooms, Study, and Halls Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Why do some electricians prefer to have more than one circuit feeding a room? It is good practice in large areas to have more than one circuit feeding the lighting circuits because if there is a problem on one circuit all power to the room is not lost. 2. Is it good practice to have outlets on different floors on the same circuit? Why? No, this is not recommended. In some localities it is against local code regulations. 3. What usually determines the grouping of outlets into a circuit? • CEC requirements for maximum number of outlets • Ease of wiring • Installation costs 4. The continuous load on a lighting branch circuit must not exceed 80 % of the branchcircuit rating. 5. To determine the maximum number of outlets in a circuit, 1.0 amperes per outlet are allowed. For a 15-ampere circuit, this results in a maximum of 12 outlets. 6. For this residence, what are the estimated wattages used in determining the loading of Branch-Circuit A16? Receptacles 120 watts (volt-amperes) Closet recessed fixture 60 watts (volts-amperes) 7. With respect to Rule 8–104(1), the ampere rating of Circuit A16 is 15 amps. 8. What size of wire is used for the lighting circuit in the front bedroom? #14 AWG 9. How many receptacles are connected to this circuit? 10 receptacles 10. What main factor influences the choice of wall boxes? The number of conductors entering and leaving the box and the devices to be mounted to the box. 11. How is a wall box grounded? By installing NMSC or AC90 cable, which contains a bare copper bonding conductor. This conductor is connected to the separate bonding screw in the box.

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12. What is a split-switched receptacle? A duplex receptacle with one outlet connected directly to the hot wire, which is on continuously. The other outlet is connected to the wire that is controlled by the switch. Split-circuit receptacles may also be used for individual circuiting of each outlet. 13. Is the switched portion of an outlet mounted toward the top or the bottom? Why? The switched portion is mounted at the bottom so that any lamp cord plugged into the switched section does not hang in front of the unswitched portion. 14. The following questions pertain to lighting fixtures in clothes closets. a. Does the CEC allow bare incandescent lamp fixtures such as porcelain keyless or porcelain pull-chain lampholders to be installed? No b. Does the CEC allow bare fluorescent lamp fixtures to be installed? No c. Does the CEC permit pendant fixtures or pendant lampholders to be installed? No. Rule 30-204. 15. How many switches are in the front bedroom circuit, and of what type are they? Three single-pole, single-throw. 16. The following is a layout of the lighting circuit for the front bedroom. Using the cable layout shown in Figure 11–6, make a complete wiring diagram of this circuit. Indicate the colour of each conductor.

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17. When planning circuits, how should you divide loads? Loads are divided as evenly as possible among circuits, and there is a maximum of 12 outlets on a two-wire circuit. 18. The CEC uses the terms watts, volt-amperes, and kW. Explain their significance in calculating loads. On an AC circuit, the only time that watts equals volt-amperes, or when kW equals kVA, is for a pure resistive circuit (100% power factor). If wattage values are used for calculations for other than resistive loads (such as motor load), it is likely that a smaller current draw than the actual value will be calculated. Using VA and kVA values ensures that the actual current draw will be obtained. 19. How #14 AWG conductors are permitted in a device box that measures 76 × 51 × 64 mm (3 × 2 × 2½ in.)? Eight #14 AWG.

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20. A 102 × 38 mm (4 × 1½ in.) octagon box has one cable clamp, one fixture stud, and three wire connectors. How many #14 AWG conductors are permitted? Box 10 Less one for connectors -1 Less one for stud -1 Total 8 Clamps don’t count. Rule 12-3036(5). 21. What circuit supplies the master bedroom? A 14 22. For the recessed closet fixtures, what wattage was used for calculating their contribution to the circuit? 60 watts each; total 120 watts (150 VA) 23. What is the estimated load in volt-amperes for the circuit supplying the master bedroom? 920 volt-amperes 24. The sliding door in the master bedroom could affect the number of required receptacle outlets. Answer the following statements True or False. a. Sliding glass panels are considered to be wall space. False b. Fixed panels of glass doors are considered to be wall space. False. Any space occupied by glass panels that extend to the floor, as is the case with most patio doors, are not considered to be usable wall space. 25. What type of receptacle will be installed outdoors, just outside of the master bedroom? A GFCI receptacle protected by a weatherproof cover. 26. Based on the total estimated load calculations, what is the current draw on the study/bedroom lighting circuit? I = VA/E = 700 = 5.83 Amperes 120 27. The study/bedroom is connected to Circuit A16 lighting, A18 AFCI receptacles. 28. The conductor for this circuit is #14 AWG copper.

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29. Is it necessary to install a receptacle in the wall space leading to the bedroom hallway? Rule 26-712(c) includes as usable wall space sections that are 900 mm or greater in width. In order to satisfy this requirement, a receptacle should be installed. 30. Show calculations needed to select a properly sized box for the receptacle outlet mentioned in Question 29. Non-metallic-sheathed cable is the wiring method. Refer to Quick-Check Box Selector Guide, Figure 5-16 in Unit 5. # Conductors from figure a14-1 4 # Wire Connectors 0 # Devices on Single Strap 1 Therefore, 2 additional conductors Total 6 conductors A standard 3 x 2 x 2-1/2 box would be suitable. The smallest size box permitted would be 3 x 2 x 2. 31. Using the cable layout shown in Figure 11–13, make a complete wiring diagram of Circuit A16.

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32. The following is a layout of the lighting circuit for the master bedroom. Using the cable layout shown in Figure 11–12, make a complete wiring diagram of this circuit. Indicate the colour of each conductor.

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NOTE: The switch boxes that house the 3W and S/P need to be deep boxes as the wire count is high so you need deeper boxes. 33. Using the electrical plans supplied with this text, lay out the devices and wiring in the master bedroom according to minimum CEC standards. Review the diagram to see if okay.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 12 Branch Circuits for the Living Room and Front Entry Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. How many convenience receptacles are connected to the living room circuit? Nine. 2. a. How many wires enter the switch box at the four-way switch location? # Conductors from Figure 12-1 6 # Wire connectors 0 # Devices on single strap 1 therefore, 2 additional conductors Total 8 conductors b. What type and size of box may be installed at this location? A standard 3 x 2 x 2-1/2 box would be suitable. 3. a. What is meant by incandescent lamp inrush current? The cold resistance of a tungsten filament lamp is very low. When the lamp is energized, an extremely high in-rush current results. The temperature and resistance of the tungsten filament increase very rapidly and reduces the current to normal levels. T-rated switches are required on tungsten loads. b. Does the CEC require T-rated switches for incandescent lamps in dwelling units? Rule 14-508(b). 4. Complete the wiring diagram for the dimmer and lamp.

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5. What is the difference between a split-switched receptacle and a split-wired (three-wire) receptacle? A split-switched receptacle has one circuit with one half of a duplex receptacle switched and the other half live. A split-wired receptacle has two separate circuits feeding the duplex receptacle. 6. How many branch circuits are required for 1. a split-switched receptacle? One. 2. a split-wired (three-wire) receptacle? Two. 7. Explain why fluorescent lamps having the same wattage can draw different current values. The current ratings must be checked for various types of ballasts because the current draw depends on the power factor of the ballast-lamp combination. The lower the power factor rating, the higher the current draw. 8. What is the total current consumption of the track lighting? I = VA/E = 200/120 = 1.67 amperes 9. a. How many television outlets are provided in the living room? Three. b. What symbol is used on the drawing to indicate the TV outlet? The symbol for the TV outlet can be found in Figure 2-10E of Unit 2 of the textbook. TV

10. a. Where is the telephone outlet located in the living room? On the wall between the master bedroom and living room. b. What symbol is used on the drawing to indicate the telephone outlet? The symbol for the telephone outlet can be found in Figure 2-10E of Unit 2 of the textbook.

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11. A layout of the outlets, switches, dimmers, track lighting, and recessed fixtures is shown in the following diagram. Using the cable layout shown in Figure 12-1, make a complete wiring diagram of this circuit. Use coloured pencils or marking pens to indicate conductors.

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12. Must track lighting always be fed (connected) at one end of the track? No, the track may be fed at any point on the track using approved fittings. 13. If there is a 7-m piece of track lighting, how many outlets is this considered to have? (7 m is 23 ft.) Rule 8-2001(a). Determine by branch connected devices. Not to exceed 12 amperes. Also track fixture size to be considered. 14. Using the electrical plans provided, lay out devices and wiring in the living room area to minimum CEC standards. Since there are many variations of acceptable layouts, each will have to be evaluated independently.

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15. a. How many circuit wires enter the front entry ceiling box? Five. b. How many equipment bonding conductors enter the front entry ceiling box? Two. 16. How many receptacle outlets and lighting outlets are supplied by Circuit A15? Feed from the six gang box, the following spread to this feeder is as follows: Feeding the recess closet light (1) Ceiling fixture in entry area (1) Living room track light (1) The porch bracket fixture (1) The two-bracket fixture in the front of the garage (2) One receptacle outlet in the entry (1) Post light in the front lawn (1) Table 12-2 lays this out. Total: 8 17. Outdoor fixtures directly exposed to the weather must be marked as [circle the correct answer] a. suitable for damp locations. b. suitable for dry locations only. c. suitable for wet locations. 18. Make a materials list of all types of switches and receptacles connected to Circuit A15. • One duplex receptacle • Five single-pole switch • One single-pole incandescent dimmer • Two three-way switches 19. The following layout is for lighting Circuit A15, the entry, porch, and front garage lights. Using the cable layout shown in Figure 12–15, make a complete wiring diagram of this circuit. Use coloured pencils to indicate the colour of the conductors’ insulation.

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20. Using the electrical plans provided with this text, lay out the devices and wiring, including circuit numbers, for the front porch and entry to minimum CEC standards. Since there are many layout possibilities that will meet the minimum standards of the CEC, the instructor must evaluate each student’s answers.

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Unit 13 Branch Circuits for Bathrooms Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. Most appliances of the type commonly used in bathrooms, such as hair dryers, electric shavers, and curling irons, have two-wire cords. These appliances are double insulated. Rule 10-408(3) and Appendix B. 2. The CEC requires that all receptacles in bathrooms be GFCI protected. 3. Draw the symbol or other markings used to identify double-insulated equipment. Rule 10-408(3) and Appendix B.

BATHROOM CEILING HEATER CIRCUITS

K

J

1. What is the wattage rating of the heat/vent/light/night light? 120 x 14.9 = 1788 watts 2. To what circuits are the heat/vent/lights connected? A11 and A13 3. What type of box would you use for the rough-in of the switch assembly for the heat/vent/light? Two-gang switch boxes, which can accommodate the switches for the AK965 unit and a single gang for the vanity light. Why? As required by the manufacturer of the heat/vent/light/night-light combination unit (AK965) supplied by Air King ventilation products. 4. a. How many wires are required to connect the control switch and the heat/vent/light/night light? Five + bonding conductor. b. What size of wires are used? #12 AWG 5. Can the heating element be energized when the fan is not operating? No. Separate heater fan comes on with heater. 6. Can the fan be turned on without the heating element? Yes. Unit has separate ventilating fan. 7. What device can be used to provide automatic control of the heating element and the fan of the heat/vent/light? Thermostat

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8. Where does the air enter the heat/vent/light? Through the outer grille. 9. Where does the air leave this unit? Air is exhausted through the discharge duct. 10. Who is to furnish the heat/vent/light? The electrical contractor. See the specification, Appendix A. 11. For a ceiling heater rated 1200 watts at 240 volts, what is the current draw? I = P/E = 1200/240 = 5 amperes

HYDROMASSAGE BATHTUB CIRCUIT

A

1. What circuit supplies the hydromassage bathtub? A9 2. Should the circuit supplying the hydromassage bathtub have GFCI protection? Yes. Rule 68-302. 3. What conductor size feeds the hydromassage tub? #14 AWG 4. What is the fundamental difference between a hydromassage bathtub and a spa? Hydromassage bathtub: Fill – use – drain. Spa: Fill – use – do not drain after each use. 5. What rules of the CEC refer to hydromassage bathtubs? Rules 68-300 to 68-308. 6. Must the metal parts of the pump and power panel of the hydromassage tub be grounded? Yes, they must be bonded to the ground. 7. Where should the electric controls be located for the hydromassage tub? The on-off device must be located not less than 1 m horizontally from the wall of the hydromassage bathtub, unless it is behind a barrier.

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8. Complete the wiring diagram below.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 14 Lighting Branch Circuit and Small-Appliance Circuits for the Kitchen Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What provision does the CEC require for microwave ovens in enclosures? A receptacle on a separate circuit. What is the relevant rule number? Rules 26-710 (h)(iii)(v) and 26-722(d). 2. What circuit feeds the kitchen lighting? What size of conductors is used? Panel B circuit B7. #14 AWG copper wire. 3. How many lighting fixtures are connected to the kitchen lighting circuit? Six, plus light in range hood. 4. Which colour of fluorescent lamps are recommended for residential installations? Deluxe warm white (WWX), or warm white (WW), or deluxe cool white (CWX). 5. a. What is the minimum number of 15-ampere split circuits or 20-ampere circuits required for a kitchen according to the CEC? Rule 26-712 (d)(iii,iv,v): (iii) a sufficient number of receptacles (5-15R split or 5-20R) along the wall at counter work surfaces (excluding sinks, built-in equipment, and isolated work surfaces less than 300 mm long at the wall line) so that no point along the wall line is more than 900 mm from a receptacle measured horizontally along the wall line; (iv) at least one receptacle (5-15R split or 5-20R) installed at each permanently fixed island counter space with a continuous long dimension of 600 mm or greater and a short dimension of 300 mm or greater; (v) at least one receptacle (5-15R split or 5-20R) installed at each peninsular counter space with a continuous long dimension of 600 mm or greater and a short dimension of 300 mm or greater. b. How many are there in this kitchen? 2-20A circuits. B13 and B15.

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6. How many duplex receptacle outlets are provided in the kitchen? 3 5-20RA on the wall behind the counter. 1 5-20RA on the island. 1 5-15R in the eating area of the kitchen. 1 5-15 R for the microwave +1 5-15R for the refrigerator 7 in total 7. What is meant by the term split-circuit receptacle? A receptacle to which two circuits may be connected. Each outlet of the receptacle is capable of being connected to a separate circuit. The CEC calls this a multiwire branch circuit. Also, part of the split-circuit receptacle may be switch-controlled. 8. A single receptacle connected to a circuit must have a rating not less than the ampere rating of the circuit. 9. In kitchens, receptacles along the countertop must be installed no farther than 900 mm apart. Rule 26-712(d)(iii) 10. A fundamental rule regarding the grounding of metal boxes, fixtures, and so on is that they must be grounded when “in reach of a grounded surface.” Rule 26-712(d) 11. How many circuit conductors enter the box a. in the track lighting ceiling box over the eating area? 9 b. at the two-gang switch located to the right of the sliding door? 13 12. How much space is there between the countertop and upper cabinets? 750 mm 13. Where is the speed control for the exhaust fan located? On the range hood unit. 14. Who furnishes the range hood? Electrical contractor; see specifications. 15. List the appliances in the kitchen that must be connected. Built-in oven; built-in countertop cooking unit; dishwasher; food waste disposer; range hood fan/light.

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16. Complete the wiring diagram below by connecting feedthrough GFCI 1 to protect receptacle 1, both to be supplied by Circuit A1. Connect feedthrough GFCI 2 to also protect receptacle 2, both to be supplied by Circuit A2. Use coloured pencils or pens to show insulation colours. Assume that the wiring method is EMT, where more freedom in the choice of insulation colours is possible.

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17. Each 15-ampere appliance circuit load demand shall be determined at [circle one] (1440 watts) (1500 watts) (1800 watts). 18. It is permitted to connect an outlet supplying a clock receptacle to the branch circuit dedicated to the refrigerator circuit. [Circle one.] (True) (False) True. If the receptacle is a recessed clock receptacle. Rule 26-722(a). 19. a. It is permitted to connect a receptacle in the dining area of a kitchen to one of the kitchen split circuits. [Circle one.] (True) (False) What CEC rule applies to this situation? Rule 26-724(b)(ii). b. Receptacles located above the countertops in the kitchen must be supplied by at least two 15-ampere, three-wire circuits. 20. The following is a layout for the lighting circuit for the kitchen. Complete the wiring diagram using coloured pens or pencils to show the conductors’ insulation colour.

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21. a. According to Rule 26–712(a), no point along the floor line shall be more than 1.8 m from a receptacle outlet. b. According to Rule 26–712(c), a receptacle must be installed in any wall space 0.9 m wide or greater. 22. The CEC states that in multiwire circuits, the screw terminals of a receptacle must not be used to splice the neutral conductors. Why? Quote the rule number. This is so that the receptacle may be removed without breaking the identified conductor circuit to the next receptacle. Section 4-036 (4). 23. Exhaust fans produce noise. It is possible to compare the noise levels of different fans before installation by comparing their sone ratings. 24. Is it permitted to connect the white grounded circuit conductor to the grounding terminal of a receptacle? No.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 15 Special-Purpose Outlets for Ranges, Counter-Mounted Cooking Units , Wall-Mounted Ovens Food Waste Disposals , and Dishwashers

,

Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. COUNTER-MOUNTED COOKING UNIT CIRCUIT 1. a. What circuit supplies the counter-mounted cooking unit in this residence? B2-4 b. What is the rating of this circuit? 40 amperes 2. What methods may be used to connect counter-mounted cooking units? • By running the supply cable to a junction box attached to the appliance. • By running the supply cable to a junction box attached to a length of flexible conduit furnished by the appliance manufacturer. • By running the supply cable to a range receptacle of adequate capacity, then attaching a cord set to the appliance. (This cord set is usually supplied with new appliances.) Rules 26-710(h), 26-744(7). 3. Is it permissible to use standard 90°C insulated conductors to connect all countermounted cooking units? Why? Not necessarily. Check the appliance label to see if there is a requirement for a conductor with a higher temperature rating. 4. Indicate the maximum operating temperature (in degrees Celsius) for the following. a. Type TW conductors 60°C b. Type TWN75 conductors 75°C c. Type R90 conductors 90°C 5. May NMWU cable be used to connect counter-mounted cooking units? Yes, as long as the cable is sized from the appropriate table to carry the correct ampacity based on the rating of the appliance and the unit nameplate indicates the supply conductors may be rated for 60°C. 6. a. What CEC rule applies to bonding a counter-mounted cooking unit? Rule 10-400 b. How is the counter-mounted cooking unit bonded to ground? Through a separate bonding conductor run with the circuit conductors.

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7. a. What is the mounting height of the receptacle supplying a range? Not to exceed 130 mm to the centre of the receptacle. Rule 26-744(6)(a). b. In which direction should the U-ground slot be oriented? Either side. Rule 26744(6)(c). c. Give the CEC section number and rule. Rule 26-744(6)(a,c). 8. When the voltage to an element is doubled, the wattage [circle one] a. increases. b. decreases. 9. One kilowatt equals 3412 Btu per hour. 10. How much heat will a 1000-watt heating element produce if operated continuously for 1 hour? 3114 x 24 x 365 = 27,278,640 BTU WALL-MOUNTED OVEN CIRCUIT

F

1. To what circuit is the wall-mounted oven connected? Circuit B6-8. 2. An oven is rated at 7.5 kW. This is equal to a. 7500 watts. b. 31.2 amperes at 240 volts. 3. a. What section of the CEC governs the bonding of a wall-mounted oven? Rule 10-400. b. How are wall-mounted ovens bonded to ground? Through a separate bonding conductor run with the circuit conductors. 4. What is the type and rating of the overcurrent device protecting the wall-mounted oven? Two-pole, 40-ampere, 240-volt circuit breaker. 5. How many metres of cable are required to connect the oven in the residence? 4 m Note: Connection point at oven is unknown; therefore, vertical measurement is from bottom of panel to top of oven, approximately 3 m, horizontal measurement is approximately 700 mm, and 300 mm is allowed for connections.

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6. When connecting a wall-mounted oven and a counter-mounted cooking unit to one feeder, how long are the taps to the individual appliances? a. The conductors feeding a fixed cooking appliance may tap off from a singlebranch circuit. If the taps do not exceed 7.5 m, their ampacity may be based on the exact amp rating of the unit they supply. If, however, their length exceeds 7.5 m, these taps must be the same size as the feeder from which they are tapped. These taps can in no case be smaller than one-third the size of the main branch circuit conductor from which they branch out. Rule 26-742(c). 7. A 6-kW counter-mounted cooking unit and a 4-kW wall-mounted oven are to be installed in a residence. Calculate the demand according to Rule 8–300(1). Show all calculations. 6 kW + 4 kW = 10 kW For a load not over 12 kW, the maximum demand may be considered as 8 kW, or 8000 watts. Rule 8-300 (1,2). 8. What size conductors will feed a. from the panel to the junction box? 8kW/240 = 33.3 amperes. Use #10 NMD90. Rated from the 75ᴼC Column. b. each of the individual units in Question 7? 6 kW – If less than 7.5 m (6000/240 = 25 amperes), use #12 NMD 90. Rated from the 75ᴼC Column. 4 kW – If less than 7.5 m (4000/240 = 16.6 amperes), use #14 NMD90. Rated from the 75ᴼC Column. 9. a. A freestanding range is rated at 11.8 kW, 240 volts. According to Rule 8–300(1), what is the demand? 8kW b. What size wire (Type NMD90) is required? #8 AWG. Rated from the 75ᴼC Column. c. What type of receptacle is required for the range? 14-50R FOOD WASTE DISPOSAL CIRCUIT DISPOSALS

H

1. How many amperes does the food waste disposal draw? 7.2 amperes 2. a. To what circuit is the food waste disposal connected? B19 b. What size wire is used to connect the food waste disposal? #14 AWG 3. Means must be provided to disconnect the food waste disposal. The homeowner need not be involved in electrical connections when servicing the disposal if the disconnecting means is a plug cap and receptacle. 4. How is running overcurrent protection provided in most waste disposal units? By built-in thermal protection.

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5. Why are flow switches sometimes installed on food waste disposals? To ensure that enough cold water flows when the food waste disposer is used. 6. What CEC sections relate to the grounding of appliances? Rule 10-400. 7. Do the plans show a wall switch for controlling the food waste disposal? Yes. 8. A separate circuit supplies the food waste disposal in this residence. How many metres of cable will be required to connect the disposal? 3.5 m DISHWASHER CIRCUIT I 1. a. To what circuit is the dishwasher in this residence connected? B15 b. What size wire is used to connect the dishwasher? #14 AWG 2. The motor on the dishwasher is [circle one] a. ¼ hp. b. ⅓ hp. c. ½ hp. 3. The heating element is rated at [circle one] a. 750 watts. b. 1000 watts. c. 1250 watts. 4. How many amperes at 120 volts do the following heating elements draw? a. 750 watts 6.25 amperes b. 1000 watts 8.33 amperes c. 1250 watts 10.4 amperes 5. How is the dishwasher in this residence grounded? Through a separate bonding conductor run with the circuit conductors. In NMSC, this is the bare conductor in the cable. 6. What type of cord is used on most portable dishwashers? Three-wire flexible cord that is suitable for damp locations; for example, SJ or SJO as listed in Table 11. 7. How is a portable dishwasher grounded? Through the bonding conductor in the flexible cord supplying the dishwasher. 8. a. What is double insulation? Two separate insulations are provided between the hot conductor and the person using the appliance or tool.

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b. What is the symbol for double insulation?

Square within a square. Rule 10-408(3), Appendix B. 9. Who is to furnish the dishwasher? The homeowner. See the specification, Appendix A. 10. Does the CEC require a separate circuit for the dishwasher? No. It is commonly recommended that it is connected to a separate circuit so that any other loads will not be affected.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 16 Branch Circuits for the Laundry, Washroom, and Attic Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. DRYER CIRCUIT AND LAUNDRY ROOM CIRCUITS 1. List the switches, receptacles, and other wiring devices that are connected to Circuit B20. Single-pole switches 4 Single-pole switch with pilot light 1 Receptacles – GFCI type 1 Exhaust fans 2 Luminaires 2 Lampholders 4 2. What CEC rule(s) refers (refer) to the receptacle required for the laundry equipment? Briefly state the requirements. Rules 26-700(11), 26-710(e)(i,ii), 26-712(a), and 26-720(b). A receptacle is required in a space intended for a washing machine. At least one other receptacle is required in a laundry room. If the washing machine receptacle is within 1.5 m of a sink, it is to be inaccessible for use with general use appliances or GFCI-protected. 3. The receptacle outlets are connected to branch circuits that have been calculated to have a maximum load of ___ watts per circuit. Circle one: 1200, 1440, 1500 watts. a. What regulates the temperature in the dryer? thermostat b. What regulates the drying time? timer 4. What is the method of connection to an electric clothes dryer? The most common is a cord and receptacle combination rated at 125/250Volts @ 30 amperes 5. What is the unique shape of the neutral blade of a 30-ampere dryer cord set? It is L-shaped and is longer than the other two hot blades. 6. a. What is the minimum number of receptacle outlets that must be installed in a laundry room? Two b. Is a separate branch circuit required? Yes c. Quote the CEC rule numbers. Rules 26-710(e)(i,ii) and 26-722(b). 7. What is the maximum permitted current rating of a portable appliance on a 30-ampere branch circuit? 30 x 0.8 = 24 amperes

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8. What is the current draw of the exhaust fan in the laundry? I = VA/E = 90/120 = 0.75 amperes 9. What special type of switch controls the attic lights? A single-pole switch that has an integral light. 10. If an attic exhaust fan draws 12 amperes at 120 volts and the ambient temperature reaches 50°C, what size and type of wire will be required to feed the fan? Refer to CEC, Table 5A. 12/0.82 = 14.63-ampere wire (Table 5A, 90ᴼC column at 50ᴼC ambient). Therefore, #14/2 NMD-90 is acceptable. 11. When installing cables in an attic along the top of the floor joists, 1.0-m clearance must not be exceeded. Rule 12-514 (a). 12. The total estimated watts for a circuit has been calculated to be 1300 volt-amperes. How many amperes is this at 120 volts? I = VA/E = 1300/120 = 10.83 amperes 13. In what circumstances would lighting and/or power be provided in an attic? Where specified by the homeowner or the architect or where the attic may contain special equipment that may need to be serviced. 14. The following is a layout of the lighting circuit for the laundry, washroom, rear entrance hall, and attic. Complete the wiring diagram using coloured pens or pencils to indicate conductor insulation colour.

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ATTIC EXHAUST FAN CIRCUIT

L

1. What is the purpose of the attic exhaust fan? To maintain the attic temperature at a level near to the outside air temperature. 2. At what voltage does the fan operate? 120 volts 3. What is the horsepower rating of the fan motor? ¼ HP 4. Is the fan direct-driven or belt-driven? Direct-driven. 5. How is the fan controlled? By a thermostat. 6. What is the setting of the running overload device? 7.25 amperes. 7. What is the rating of the running overload protection if the motor is rated at 10 amperes? 10 x 1.25 = 12.5 amperes

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8. What is the basic difference between a thermostat and a humidistat? A thermostat switching mechanism operates with a bimetallic element that is sensitive to changes in temperature. A humidistat contains a nylon element that is sensitive to changes in humidity to operate the switching mechanism. 9. What size of conductors are to be used for this circuit? #14 AWG 10. How many metres of cable are required to complete the wiring for the attic exhaust fan circuit? 9m 11. May the metal frame of the fan be grounded to the grounded circuit conductor? No 12. What CEC rule prohibits grounding equipment to a grounded circuit conductor? Rule 10-204 (1)(c).

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Unit 17 Electric Heating and Air Conditioning Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. ELECTRIC HEAT 1. a. What is the allowance in watts made for electric heat in this residence? 13 kW b. What is the value in amperes of this load? I= P/E = 13000/240 = 54.17 amperes 2. What are some of the advantages of electric heating? • Electric heating is safer than a fuel combustion system. • It is clean. • It has the capability for individual room control. • It is quiet in operation. • It requires a minimal amount of maintenance. 3. List the different types of electric heating system installations. Baseboard, wall-mounted, floor-mounted, embedded cable in ceiling or floor, central furnace, duct heaters, heat pumps. 4. There are two basic voltage classifications for thermostats. What are they? Line-voltage and low-voltage thermostats. 5. Which device is required when the total connected load exceeds the maximum rating of a thermostat? A relay of adequate capacity. 6. The electric heat in this residence is provided by what type of equipment? An electric furnace. 7. At what voltage does the electric furnace operate? 240 volts. 8. A certain type of control connects electric heating units to a 120-volt supply or a 240-volt supply, depending on the amount of the temperature drop in a room. These controls are supplied from a 120/240-volt, three-wire, single-phase source. Assuming that this type of device controls a 240-volt, 2000-watt heating unit, what is the wattage produced when the control supplies 120 volts to the heating unit? Show all calculations. P = E2 / R = (E x E) / R. If you solve for R = E2 /P, you get 28.8 ohms. The resistance of the baseboard never changes; all you can change is the amount of voltage you apply to it. If you use 28.8 ohms and multiply it by 120 volts, you get 500 watts. When the voltage is reduced to one-half the rated value, the wattage is reduced to one-quarter of its rated value.

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9. What advantages does a 240-volt heating unit have over a 120-volt heating unit? For the same wattage rating, the current draw at 240 volts is one-half of the current draw at 120 volts. This can result in the use of smaller conductors, smaller raceways, less voltage drop (IR), and less watts loss (I² R) in the conductors. 10. a. The white wire of a cable may be used to connect to a hot circuit conductor only if The white conductor is made permanently unidentified or cable is armoured cable, NMSC, or aluminum-sheathed cable used for S.P.S.T three-way or fourway switch loops. b. Quote the rule number. Rule 4-036(1)(2). 11. Electric baseboard heaters shall not be installed beneath wall receptacle outlets. Explain and quote the CEC rule. Receptacles should not be located so that the cord will pass over the baseboard heaters. Rule 26-712(a), Appendix B. 12. [Circle the correct answer.] The branch circuit supplying a heater shall have an ampacity of a. not less than the connected load supplied. Rule 62-110(1)(b) b. 125% of the current rating of the heater. 13. Compute the current draw of the following electric furnaces. The furnaces are all rated 240 volts. a. 7.5 kW I = P/E = 7500/240 = 31.25 amperes b. 15 kW I = P/E = 15000/240 = 62.5 amperes c. 20 kW I = P/E = 20000/240 = 83.3 amperes 14. The wattage output of a 240-volt electric furnace connected to a 208-volt supply will be about 75% of the wattage output if the furnace is connected to a 240-volt supply. Referring to Question 13, calculate the wattage output of (a), (b), and (c) if the furnace is connected to a 208-volt supply. a. 7.5 x 0.75 = 5.625 kW b. 15 x 0.75 = 11.25 kW c. 20 x 0.75 = 15 kW 15. A central electric furnace heating system is installed in a home. Should a separate branch circuit supply this furnace? Explain. Yes. Heating equipment is required to be on branch circuits devoted to heating equipment only. 16. What CEC rule provides the answer to Question 15? Rule 62-110(1)(a), Rule 62-114(1).

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AIR CONDITIONING 1. When calculating air-conditioner load requirements and electric heating load requirements, is it necessary to add the two loads together to determine the combined load on the service? Explain your answer. For loads that are not likely to be operated at the same time, the smaller of the two loads may be omitted. However, many inspection authorities require that the loads be interlocked such that only one load may operate at a time. Otherwise, both loads must be included. Rule 8-106 (4). 2. The total load of an air conditioner shall not exceed what percentage of a separate branch circuit? [Circle one of the following.] a. 75% b. 80% c. 125% 3. Do window air conditioners count as a connected load when calculating the demand watts on a service? Only if the total rating is greater than the heating load. Rule 8-200(1)(a)(iii). However, since these loads are not interlocked, many inspection authorities may require that both loads be included. 4. Must an air conditioner installed in a window opening be bonded to ground? Yes. 5. A 120-volt air conditioner draws 12 amperes. What size is the circuit to which the air conditioner will be connected? 15 amperes 6. When a central air-conditioning unit is installed and the label states “Maximum size fuse 50 amperes,” is it permissible to connect the unit to a 50-ampere circuit breaker? Only if the AC unit has a listing of 50 amperes for the circuit breaker as well. In other words, the overcurrent protection for a particular piece of equipment is listed on the label of the equipment in order for it to be certified by CSA. 7. What CEC rule prohibits installing Class 2 control circuit conductors in the same raceway as the power conductors? Rule 16-212(3). The Class 2 conductors may be run in the same raceway only if separated by an acceptable barrier.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 18 Oil and Gas Heating Systems Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. How is the residence in the text heated? Electric heat (furnace). 2. Where does the CEC require that a disconnecting means be installed for a furnace or boiler? It requires that the disconnecting means be located between the furnace and the point of entry to the area where the furnace is located. Not to be located on the furnace. Rule 26-806(6,7). 3. What device in an oil-burning system will shut off the burner in the event of a flame-out? The primary control, sometimes called the “stack” switch. 4. Name the control that limits dangerous water temperatures in a boiler. Liquid immersion control. This is also provided through an aqua-stat, which connects to the outside of the water line leaving the boiler. 5. Name the control that limits the temperature in the plenum of a furnace. Limit control, sometimes called a limit switch. 6. In the wiring diagrams in this unit, are the safety controls connected in series or parallel? Series. 7. What is meant by the term “self-generating”? “Self-generating” means that the system does not require a separate power supply. The system generates its own power by means of a thermopile. 8. Because a self-generating unit is not connected to an outside source of power, the electrician need not use care in selecting the conductor size or making electrical connections. Is this statement true or false? Explain. False. Regardless of the type of burner to be installed, the electrician must always use care in making connections. Because the power in a self-generating system is very low, the circuit resistance must be kept as low as possible by using correct extension wire for the thermocouples and by ensuring that all connections are secure. 9. Explain what a thermocouple is and how it operates. A thermocouple is two unlike metals joined together so that a complete circuit is formed. Electric current will flow when one junction is heated and the other junction remains cold. This can then be calibrated to measure the temperature at the end of the thermocouple.

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10. Explain what a thermopile is. A thermopile is a series of thermocouples connected in series to produce a greater voltage and subsequently a greater current. 11. If Class 2 extra-low-voltage conductors are insulated for 32 volts, and the power conductors are insulated for 600 volts, does the CEC permit pulling these conductors through the same raceway? No. Rule 16-212(3). 12. If Class 2 extra-low-voltage conductors are used on a 24-volt system but are actually insulated for 600 volts (T90 nylon No. 14, for example), does the CEC permit running these conductors together in the same raceway as the 600-volt power conductors? No. Except if the power conductors are supplying power to the Class 2 circuit. Rule 16-212(4). 13. Under what conditions may Class 1 conductors and power conductors be installed in the same raceway? If insulated for the maximum voltage of any conductor, and connected to the same piece of equipment. 14. What is the CEC section and rule for Question 13? Rule 16-114(2).

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Unit 19 Recreation Room Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What is the total current draw when all six fluorescent fixtures are turned on? I = VA/E = 936/120 = 7.8 amperes 2. How many #14 AWG conductors will enter the junction box that will be installed above the dropped ceiling near the fluorescent fixtures closest to the stairway? Seven total conductors: three from the switch (power, return and neutral); two going to the next branch light return and neutral; and two to feed the receptacle power and neutral. 3. Why is it important that the hot conductors in a three-wire circuit be properly connected to opposite phases in a panel? Because of the possibility of overloading the neutral conductor. 4. In the diagram, Load A is rated at 10 amperes, 120 volts, and Load B is rated at 5 amperes, 120 volts.

a. When connected to the three-wire circuit as indicated, how much current will flow in the neutral? The neutral carries the unbalanced load of 10 – 5 = 5 amperes. b. If the neutral should open, to what voltage would each load be subjected, assuming both loads were operating at the time the neutral opened? Show all calculations. Load A: R = E/I = 120/10 = 12 ohms Load B: R = E/I = 120/5 = 24 ohms With an open neutral, A and B are in series, therefore, RT = 12 + 24 = 36 ohms IT = E/RT = 240/36 = 6.66 amperes

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Therefore:

Load A: E = I x R = 6.66 x 12 = 80 volts Load B: E = I x R = 6.66 x 24 = 160 volts

Load B will be damaged due to high voltage. 5. Calculate the watts loss and voltage drop in each conductor in the following circuit.

15.24m #12 AWG SOLID COPPER

15 ampere

15.24m #12 AWG SOLID COPPER

1000 ft. of #12 AWG solid copper wire has 1.93-ohms resistance. Therefore, 50 ft. would have 0.0965-ohms resistance. Power = I x I x R = 15 x 15 x 0.0965 = 21.7 watts per wire. Voltage drop = I x R = 15 x 0.0965 = 1.4475 volts per wire. At 120 volts applied to the circuit, the 2.9 volts dropped on the wires is less than the 3.6 volts (3%) permitted by the Code. 6. Unless specifically designed, all recessed incandescent fixtures must be provided with factory-installed marking to indicate if the fixture is suitable for insulation contact. 7. If the fluorescent fixtures in the recreation room were to be mounted on the ceiling, what sort of marking would you look for on the label of the fixture? The ceiling is low-density cellulose fibreboard. Suitable for surface mounting. 8. What is the current draw of the recessed fixtures above the bar? Four fixtures at 60 watts each: 60 x 4 = 240 watts I = P/E = 240/120 = 2.0 amperes 9. Calculate the total current draw for Circuits B10, B12, and B14. Based on the estimated load for: B10 240 VA / 120 = 2A B12 1140 VA / 120 = 9.5A B14 966 VA / 120 = 8.05A

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10. Complete the wiring diagram for the recreation room. Follow the suggested cable layout in Fig 19-2. Use coloured pencils or pens to identify the various colours of the conductor insulation.

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11. a. May a fluorescent fixture that is marked “Recessed fluorescent fixture” be installed in a suspended ceiling? Yes. b. May a fluorescent fixture that is marked “Suspended ceiling fluorescent fixture” be installed in a recessed cavity of a ceiling? No. The fixture must be approved for the location that it is being installed in. c. What CEC, Part I, section covers the installation of recessed fixtures? Rules 30-900 to 30-912. 12. Using Table D3 in Appendix D, calculate the maximum distance for a #12/2 NMD90 wire carrying 10 amperes at 240 volts if a 3% voltage drop is on the cable. Answer in metres. Show calculations. Table D2 dist. x % v.d. x D.C.F. x volts/120 = Max. distance. 9.8 m x 3 x 1.06 x 240 = 62.33 m maximum. 120 The Table D3 distance is obtained from the 10-ampere line and the No. 12 column = 9.8 m. The maximum % voltage drop is 3%. The wire is 90°C wire at 50% load; therefore, from the table in note 3 of Table D3 the distance correction factor is 1.06. 13. Using the plans provided with this textbook, complete a device and wiring layout for the recreation room area to minimum CEC standards. Because there are many possible layouts that meet the minimum requirements of the CEC, each answer must be independently evaluated.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 20 Branch Circuits for Workshop and Utility Area Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. WORKSHOP 1. a. What circuit supplies the workshop lighting? A17 b. What circuit supplies the plug-in strip over the workbench? A19 c. What circuit supplies the freezer receptacle? A12 2. What types of lighting fixtures are installed on the workshop ceiling? Four lampholders (two keyless) that mount directly to the outlet boxes, plus the fluorescent fixtures above the workbench. 3. Does a receptacle for a freezer have to be GFCI-protected? Explain. No. The same reasoning as for the smoke detectors applies. A slight “leakage” could cause the GFCI to trip to the off position, resulting in spoiled food. 4. Does a receptacle for a sump pump have to be GFCI-protected? Explain. No. This is a good example of a “dedicated receptacle,” which should be on a dedicated circuit for the sump pump. If connected to a GFCI-protected circuit, the receptacle or breaker could trip and the basement could be flooded. 5. When a 120-volt receptacle is provided for the laundry equipment in a basement, what is the minimum number of additional receptacle outlets required? What is the CEC reference? The CEC, Part I, requires one duplex receptacle in the space intended to accommodate a washing machine. It also requires at least one in a utility room or area and one in an unfinished basement area, and an additional one in a laundry room. Rule 26-710(e)(i). 6. When a single receptacle is installed on an individual branch circuit, the receptacle must have a rating not less than the rating of the branch circuit. The voltage and current must correspond to the rating of the configuration of the receptacle. Rule 26-722(f). 7. Calculate the total current draw of Circuit A17 if all lighting fixtures and the exhaust fan were turned on. I = VA/E = 656 = 5.47 amperes 120 8. If a #10 NMD90 cable is located in an ambient temperature of 42°C, what would be the temperature correction factor? From Table 5A in the 90°C column at 45°C ambient temperature, the correction factor is 0.87.

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9. What size of box would you use where Circuit A17 enters the junction box on the ceiling? This box has six #14 AWG conductors. A 4” x 1 ½” octagon box would be suitable. 10. The following is a layout of the lighting circuits for the workshop. Using the conduit layout in Figure 20-1, make a complete wiring diagram. Use coloured pencils or pens to indicate conductors.

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Electrical Wiring: Residential, Seventh Canadian Edition

WATER PUMP CIRCUIT

B

1. How is the motor disconnected if pumping is no longer required? By the double-pole breaker in Panel A and the disconnect switch next to the pump controller location. Normal start-stop operations are controlled by the pressure switch. 2. Why is a 240-volt motor preferable to a 120-volt motor for use in this residence? A 240-volt motor operates using one-half the current used by a 120-volt motor. Lower current results in lower line loss. 3. How many amperes does a 1-hp, 240-volt, single-phase motor draw? (See Table 45.) 8 amperes 4. What size are the conductors used for this circuit? Copyright © 2016 by Nelson Education Ltd.

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#12 AWG conductors to be used for the pump circuit. Special-purpose outlets, see Table A-1. 5. a. What is the branch-circuit protective device? Circuit A5,7 is a 20-ampere double-pole overcurrent device in Panel A. b. What furnishes the running protection for the pump motor? A double-pole thermal overload switch mounted next to the pump. For submersible pumps, the controller contains the overload protection. Back-up overload protection is accomplished by installing Fusetron dual-element fuses in the disconnect switch. c. What is the maximum ampere setting required for running protection of the 1-hp, 240volt pump motor? 10 amperes = (8 x 1.25). Rule 26-106(1). 6. [Circle correct answer.] Submersible water pumps operate the electrical motor and actual pump located a. above the permanent water level. b. below the permanent water level. c. half above and half below permanent water level. 7. Because the controller contains the motor starting relay and the running and starting capacitors, the motor itself contains no moving parts, i.e., relays or switches for capacitors. 8. What type of pump moves the water inside the deep-well pipe? Centrifugal pump. 9. Proper pressure of the submersible pump system is maintained by a pressure switch. 10. Fill in the data for a 16-ampere electric motor, single-phase, 1.15 service factor. a. Branch-circuit protection, nontime-delay fuses. Normal size: 48 (use 45) A Switch size: 60 A (Table 29) Maximum size: 64 (use 60) A Switch size: 60 A (400%) Rule 28-200(a,e), D16 Chart.

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Electrical Wiring: Residential, Seventh Canadian Edition

b. Branch-circuit protection, dual-element, time-delay fuses. Normal size: 28 (use 25) A Switch size: 30 A (Table 29) Maximum size: 36 (use 35) A Switch size: 60 A (225%) Rule 28-200(a,e), D16 Chart. c. Branch-circuit protection, instant-trip breaker. Maximum setting 208 A (13 x) (Rule 28-210(b)) d. Branch-circuit protection—inverse time breaker. Maximum setting 40 A (Table 29, D16 Chart) e. Branch-circuit conductor size. #14 AWG Ampacity 20 A 125% of FLA = 16 x 1.25= 20 A f. Motor running protection using dual-element time-delay fuses. Maximum size 20 A (Rules 28-302(2) and 28-306) 11. The CEC is very specific in its requirement that submersible electric water pump motors be grounded. Where is this specific requirement found? Rule 26-954(d). 12. Does the CEC allow submersible pump cable to be buried directly in the ground? Yes, if the cable supplied with a submersible is also approved for direct earth burial. For example, RWU75, RWU90, TWU, and TWU75. Rule 26-954.

WATER HEATER CIRCUIT

C

1. At what temperature is the water in a residential heater usually maintained? 60°C to 72°C. 2. Magnesium rods are installed inside the water tank to reduce corrosion. 3. Is a separate meter required to record the amount of energy used to heat the water? No. 4. What is meant by the phrase “flat rate” installation? The utility will want to control the power demands of its users. One way is to turn “off” the energy supply to heater loads during “peak” demand periods and reenergize during light load demand periods. The utility charges the customers with this service a “flat rate” for the equipment and energy used. 5. What is the most common method of metering water heater loads? With the water heater connected to the regular house meter and feeding the water heater directly from the panel.

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6. Two thermostats are generally used in an electric water heater. a. What is the location of each thermostat? Approximately three-quarters of the way up from the bottom of the tank and onequarter of the way up from the bottom of the tank. b. What type of thermostat is used at each location? Upper—interlocking or snap-over type Lower—single-pole, on or off variety 7. a. How many heating elements are provided in the heater in the residence discussed in this text? Two. b. Are these heating elements allowed to operate at the same time? No. 8. When does the lower heater operate? When the water in the upper part of the tank reaches 65°C and the upper thermostat snaps over, allowing the lower element to operate. 9. The CEC states that water heaters must have a temperature regulating device set at 90°C maximum. Secondary protection is by a temperature cut out set at the factory at 96°C. Rule 26-750(1,2). 10. Why does the storage tank hold the heat so long? The insulation is designed to minimize heat loss. 11. The electric water heater is connected for “limited demand” so that only one heating element can be on at one time. a. What size of wire is used to connect the water heater? #12 AWG b. What size of overcurrent device is used? 20 amperes 12. a. If both elements of the water heater are energized at the same time, how much current will they draw? (Assume the elements are rated at 240 volts.) Element No. 1 = 3000 watts Element No. 2 = 2000 watts Add the total wattage of both elements: PT = P1 + P2 = 3000 +2000 = 5000 watts I = P/E = 5000/240 = 20.83 amperes b. What size of wire is required for the load of both elements? Show your calculations. #12 AWG wire, as per Table 2. 13. a. How much current do the elements in Question 12 draw if connected to 220 volts? Show your calculations. 240/220 = 20.83/x (ratio comparison) x = 220 x 20.83/240 x = 19.094 amperes

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Electrical Wiring: Residential, Seventh Canadian Edition

b. What is the wattage value at 220 volts? Show your calculations. P=ExI P = 220 x 10.094 P = 4201 watts 14. A 240-volt heater is rated at 1500 watts. a. What is its current rating at rated voltage? I = P/E = 1500/240 = 6.25 amperes b. What current draw would occur if connected to a 120-volt supply? 120 –240 = x/6.25 x = 120 x 6.26/240 x = 3.125 amperes c. What is the wattage output at 120 volts? R = E/I = 240/6.25 = 38.4 Ω P = E2/R = 1202/38.4 = 375 watts Note: 375 watts is one-quarter the 1500 watts at rated 240 volts. Therefore, one-half the rated volts = one-quarter the rated watts, or two times the rated volts = four times the rated watts. 15. A customer asks the electrician to set the water heater thermostat 30ºC below the maximum permitted by the CEC. The thermostat is set at a. 70°C. b. 66°C. c. 60ºC. d. 49 ºC.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 21 Heat and Smoke Detectors, Carbon Monoxide Detectors, and Security Systems Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What is the name and number of the ULC standard that gives information about smoke and heat detectors? Standard for the Installation of Fire Alarm Systems, CAN/ULC-S524-M91. 2. Name the two basic types of smoke detectors. Photoelectric and ionization. 3. Why is it important to mount a smoke alarm on the ceiling not closer than 150 mm to a wall? Because this area must be considered to be dead airspace, where the possibility exists that little or no smoke or heat would reach the detector. 4. [Circle the correct answer.] A basic rule is to install smoke alarms a. between the sleeping area and the rest of the house. b. at the top of a basement stairway that has a closed door at the top of the stairs. c. in a garage that is subject to subzero temperatures. 5. List two types of thermal detectors that are used in residential fire alarm systems. Fixed temperature and rate-of-rise temperature. 6. Although the ULC gives many rules for the installation of smoke and heat detectors, always follow the installation recommendations of the manufacturer. 7. Security systems are usually installed with wire that is much smaller than normal house wires. These wires are generally #18 AWG, which is similar in size to the wiring for chimes. 8. [Circle the correct answer.] Because the wire used in wiring security systems is rather small and cannot stand rough service and abuse, security wiring should be installed during the rough-in stages of a new house (before) (after) the other power-circuit wiring is completed. 9. [Circle the correct answer.] When several smoke alarms are installed in a new home, these units must be a. connected to separate 120-volt circuits. b. connected to one 120-volt circuit. c. Interconnected so that if one smoke alarm is set off, the other will also sound a warning. 10. [Circle the correct answer.] It is advisable to connect smoke alarms to circuits that are protected by GFCI devices. True False

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11. [Circle the correct answer.] Because a smoke alarm might need servicing or cleaning, be sure to connect it so that it is controlled by a wall switch. True False 12. [Circle the correct answer.] Smoke alarms of the type installed in homes must be able to sound a continuous alarm when set off for at least a. 4 minutes. b. 30 minutes. c. 60 minutes. 13. If a carbon monoxide detector is located in the hall outside the bedrooms, what is the maximum distance the detector may be from the bedroom doors? 5m 14. If a home has an attached garage, is a CO detector required? Yes. 15. In a home with a wood-burning fireplace, where must the CO detector(s) be located? In the room with the appliance and near the bedrooms.

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Unit 22 Swimming Pools, Spas, and Hot Tubs Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. The CEC rule that covers most of the requirements for wiring swimming pools is Rule Section 68. 2. Name two ways in which a person may sustain an electrical shock when in a pool. a. By touching a “live” wire or “live” piece of equipment. b. From the voltage gradients present in the pool water resulting from a “live” wire or “live” piece of electrical equipment falling into the water. 3. Rule 68-050 discusses types of pools. Name and describe two types. Permanent: A pool constructed in such a manner that it cannot be disassembled for storage. Decorative: A pool that can be used as a wading pool, that is larger than 1.5 m in any dimension, and that is readily accessible to the public. Storable: A pool constructed in such a manner that it may be readily disassembled for storage and reassembled to its original integrity. 4. Use Section 68 to determine if the following items must be bonded. YES or NO a. Wet- and dry-niche lighting fixtures. Yes b. Electrical equipment located beyond 1.5 m of the inside edge of the pool. Yes c. Electrical equipment located within 3 m of the inside edge of the pool. Yes d. Recirculating equipment and pumps. Yes e. Lighting fixtures installed more than 7.5 m from the inside edge of pool. Yes. Must be bonded but they do not have to be bonded to the metal parts. f. Junction boxes, transformers, and GFCI enclosures. Yes g. Panelboards that supply the electrical equipment for the pool. Yes h. Panelboards 6m from the pool that do not supply the electrical equipment for the pool. No. They do not have to be bonded to the pools metal parts. Rule 68-058. 5. [Circle the correct answer.] Bonding conductors (must) (may) be run in the same conduit as the circuit conductors. Rule 10-808(7). 6. [Circle the correct answer.] Bonding conductors (may) (may not) be spliced with the wirenut types of wire connectors. Rule 10-808(2). 7. The purpose of grounding and bonding is to keep all parts at the same potential, and to facilitate the opening of the overcurrent devices if a fault occurs.

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8. What parts of a pool must be bonded together? Virtually every piece of electrical and metal equipment in, on, or around the pool must be bonded together continuous and to ground. Rule 68-058(8). 9. May electrical wires be run above the pool? Explain. No. The only exception is as listed in Rule 68-054, Appendix B. 10. What is the closest distance that a receptacle may be installed to the inside edge of a pool? 1.5 m. Rule 68-064(1). 11. Receptacles located between 1.5 m and 3 m from the inside edge of a pool must be protected by a GFCI. 12. [Circle the correct answer.] Lighting fixtures installed over a pool must be mounted at least (3 m) (4 m) (4.5 m) above the maximum water level, Rule 68-054. 13. Grounding conductor terminations in wet-niche metal-forming shells, as well as the conduits entering junction boxes or transformer enclosures where the conduit runs directly to the wetniche lighting fixture, must be watertight and provided with a (an) packing seal to prevent corrosion to the terminal and to prevent the passage of water through the conduit, which could result in corrosion, Rule 68-060(7). 14. [Circle the correct answer.] Wet-niche lighting fixtures are accessible (from the inside of the pool) (from a tunnel) (on top of a pole). 15. [Circle the correct answer.] According to Rule 68-066, wet-niche lighting fixtures shall not be submerged to a depth of not more than a. 600 mm. b. 300 mm. c. 450 mm. d. 1 m. 16. [Circle the correct answer.] Dry-niche lighting fixtures are accessible (from a tunnel, or passageway, or deck) (from the inside of the pool) (on top of the pole). 17. [Circle: True or False] In general, it is not permitted to install conduits under the pool or within 1.5 m measured horizontally from the inside edge of the pool, Rule 68-056, Table 61. Explain. Only bonding conductors or conductors supplying equipment associated with the pool may be closer than 1.5 m from the pool. Table 61 gives minimum conductor separation from the pool. 18. [Circle the correct answer.] Junction boxes, transformers, and GFCI enclosures have one thing in common. They all (are made of bronze) (have threaded hubs) (must have a bonding wire or terminal screw).

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Electrical Wiring: Residential, Seventh Canadian Edition

19. [Circle the correct answer.] Lighting fixtures are permitted to be mounted less than 3 m measured horizontally from the inside edge of the pool only if they are (approved for wet locations) (rigidly fastened to an existing structure) (GFCI-protected). 20. The following statements about indoor spas and hot tubs are either true or false. Check one. TRUE or FALSE. a. Receptacles may be installed within 1.5 m from the edge of the spa or hot tub. False. Rule 68-064(1). b. All receptacles within 3 m of the spa or hot tub must be GFCI-protected. True. Rule 68-064(2). c. Any receptacles that supply power to pool equipment must be GFCI-protected if within 3 m of the pool. True. Rule 68-064(2). d. Wall switches must be located at least 1 m from the spa or hot tub. True, if part of spa control. Rule 68-404(1). e. Lighting fixtures above the pool or within 1.5 m from the inside edge of the pool must be GFCI-protected. True. Rule 68-066(6). 21. [Circle the correct answer.] Bonding and grounding of electrical equipment in and around spas and hot tubs (are required by the CEC) (are not required by the CEC) (are decided by the electrician). 22. When installing a hot tub, a control shall be located behind a barrier not less than 1 m from the tub. 23. [Circle the correct answer.] For the circuit supplying a hydromassage or whirlpool bathtub, be sure that the circuit (does not have GFCI protection that could result in nuisance tripping) (is GFCI-protected). 24. [Circle: True or False] Leakage current collectors shall be bonded to the control panel with a minimum #6 AWG copper bonding conductor. (True) (False) Rule 68-406 (5)(b). 25. The maximum voltage that wet-niche fixtures are intended to be connected to is a. 120 volts. b. 15 volts. c. 240 volts. 26. Swimming pool pump motors shall be specifically approved, and, if within 3 m of the pool wall, shall be protected by a Class A GFCI. Quote the rule numbers. Rule 68-068(7)(d).

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 23 Television, Telephone, Data, and Home Automation Systems Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. TELEVISION CIRCUIT 1. How many television outlets are installed in this residence? Twelve: 8 first floor, 4

basement. 2. What types of boxes are recommended when unshielded lead-in wire is used? Non-metallic. 3. What determines the design of the faceplates used? The design of the other faceplates in the residence so that they match. 4. What must be provided when installing a television outlet and receptacle outlet in one wall box? A barrier must be placed between the 120-volt section and the television section of the box so that the line does not interfere with the low-voltage portion of the TV circuit and cause distortion. 5. Which system is more economical to install: a master amplifier distribution system or a multiset coupler? Explain the basic differences between these two systems. A multiset coupler distribution system is more economical than the master amplifier system. The master amplifier system is more expensive because it needs an accessible area, twin lead 300Ω cable runs to each TV outlet, a 120-volt supply, and, in general, is a more complex piece of equipment. 6. What precautions should be noted when installing a television antenna and its lead-in wires? All of the requirements are listed in outline form in the textbook starting on page 392. Refer to Section 54 of the CEC. 7. List the requirements for cable television inside the house. All of the requirements are listed in outline form in the textbook on page 389. Refer to Section 54 of the CEC. 8. What section of the CEC references the requirements for cable television antenna installation? Section 54.

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9. Grounding and bonding together all metal parts of an electrical system and the metal shield of the cable television cable to the same grounding reference point in a residence will keep both systems at the same voltage level should a surge, such as lightning, occur. If the CATV company installer grounds the metal shield of the incoming cable (to a house) to a driven ground rod, does the installation conform to the CEC ? No. Rule 10-702. 10. The basics of cable television are that a transmitter on earth sends a(n) uplink signal to a(n) satellite where the signal is reamplified and sent back to earth via the downlink signal. This signal is picked up by the feedhorn on the satellite antenna, which is sometimes referred to as a(n) dish. The feed horn funnels the signal into a(n) low noise amplifier, then onto a(n) downconverter, where the high-frequency signal is converted to a(n) low-frequency signal suitable for the television receiver. 11. [Circle the correct answer.] All television satellites rotate above the earth in (the same orbit) (different orbits). 12. [Circle the correct answer.] Television satellites are set in orbit (16 093) (28 970) (36 563) km above the earth, which results in their revolving around the earth at (precisely the same) (different) rotational speed as/from the earth. This is done so that the satellite dish can be focused on a specific satellite (once) (one time each month) (whenever the television set is used). TELEPHONE SYSTEM 1. How many locations are provided for telephones in the residence? Eight inside and one outside. 2. At what height are the telephone outlets mounted? 300 mm to centre, 1250 mm in workshop. 3. Sketch the symbol for a telephone outlet.

4. Is the telephone system regulated by the CEC? The telephone utility is exempt under the Scope (a) in Section O, page 1, of the CEC. See also Rule 60-108 with respect to (2). 5. a. Who is to furnish the outlet boxes required at each telephone outlet? Electrical contractor. b. Who is to furnish the faceplates? Electrical contractor.

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Electrical Wiring: Residential, Seventh Canadian Edition

6. Who is to furnish the telephones? The owner. 7. Who does the actual installation of the telephone equipment? The electrical specifications include the equipment, meaning the equipment will be installed by the electrical contractor or subcontracted to the telephone utility or a communications contractor. 8. How are the telephone cables concealed in this residence? The cable is installed throughout the house during construction, generally right after the electrical wiring is roughed in. 9. The point where the telephone company’s cable enters the residence and the interior telephone cable wiring meet is called the demarcation point. 10. What are the colours contained in a four-conductor telephone cable assembly and what are they used for? Green: Tip (the “negative” side of the line) Red: Ring (the “positive” side of the line) Yellow: Ground Black: For lighted handset dial 11. List the CEC rules for the installation of telephone cables in a residence. These are itemized in outline form in the textbook starting on page 395. See also Section 60 of the CEC. 12. If finger contact were made between the red conductor and green conductor at the instant a “ring” occurs, what voltage of shock would be felt? The ringing voltage can reach 90 volts AC, so a 90-volt AC shock will give a good tingle. DATA SYSTEMS 1. What is the data rate for Ethernet networks as discussed in this chapter? 100 Mbps is standard; however, some 10 Mbps networks are still installed in residential environments. 2. What precautions must be taken when installing data cable? • Use cable and terminations of the same category type. • Avoid excessive pulling force. • Maintain at least 300 mm (12”) separation from data cable and electrical equipment. • Do not over tighten straps or cable ties or bend cable at a radius of less than 25 mm (1”) as twist rates of conductors may be deformed or insulation damaged. 3. Which termination configuration is most commonly used in Canada? 568-A Copyright © 2016 by Nelson Education Ltd.

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4. What is the maximum data rate of a Category 5e network? 1000 Mbps, or 1 Gbps. 5. What is the maximum pulling force that may be exerted on a data cable? 11 kg, or 25 lb. 6. When supporting data cable, why is it important not to strap or tie the cable too tightly? Overtightening of straps or cable ties can cause changes in the twist rates of the conductors. Any change in the twist rate can result in poor performance of the network. 7. What is the minimum radius of bend of data cable and why? 25 mm, or 1”. If the cable is bent at a tighter radius, conductor insulation may be damaged and twisting of the conductors may be deformed. 8. List the factors that affect the connectivity and data transfer rate of wireless network systems. Type of building construction and signal strength. 9. What other equipment can affect a wireless data network? Metal objects between the transmitter and the computer. HOME AUTOMATION 1. What systems can be controlled using an X10-based home automation system? Almost any resistive load and inductive loads. See the list on page 386 of the textbook. 2. Is additional wiring between the controller and the controlled device required? Explain why or why not. No. X10 devices take their power from the 120-volt system in the house. 3. If the home is very large, what additional device may need to be installed? An amplifier/coupler. 4. With the alphanumeric addressing system, how many unique devices can be controlled? 256

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Unit 24 Lighting Branch Circuit for the Garage and Outdoor Lighting Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. What circuit supplies the garage? B14 (see Figure 24-1 on page 410 of the textbook). 2. What is the circuit rating? 15 amperes 3. How many receptacle outlets are connected to the garage circuit? Three 4. a. How many cables enter the wall switch box located next to the side garage door? Four (see Figure 24-1 on page 410 of the textbook) (blueprints show only three). b. How many circuit conductors enter this box? Nine c. How many bonding conductors enter this box? Four 5. Show calculations on how to select a proper box for Question 4. What kind of box would you use? Circuit conductors 9 Switches (two) 4 Connectors (three) + 1 Total conductors in box 14 14/2 = 7 conductors per box for two device boxes. Therefore, from Table 23 or the Quick Check Selection Guide, two 3 x 2 x 2 ½” boxes are adequate. 6. a. How many lights are recommended for a one-car garage? Two For a two-car garage? Three For a three-car garage? Four b. Where are these lights to be located? Along the side(s) and toward the front of the automobile(s). 7. From how many points in the garage of this residence are the ceiling lights controlled? Three 8. List three methods by which the cover requirements of CEC Table 53 can be reduced. Rule 12-012(3) lists the forms of mechanical protection that permit the cover requirements to be reduced by 150 mm. 1. 2. 3. 4.

Treated planks 38 mm thick. 50-mm poured concrete. Concrete slabs. Black poly pipe as described in Appendix B.

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9. The total estimated load of the garage circuit draws how many amperes? Show your calculations. I = VA/E = 1416/120 = 11.8 amperes 10. How high from the floor are the switches and receptacles to be mounted? 1200 mm for the switches and receptacles. 11. What type of cable feeds the post light? NMWU 12. Describe the appropriate method of backfilling trenches containing cables, conduits, and/or direct burial conductors. Quote the CEC rule: Cables or conductors must have screened sand or earth 75 mm below and above them. Any backfill with large rocks, sharp objects, or corrosive materials cannot be used. Marking tape is required halfway between installation and grade, unless some other form of marking is used. Rule 12-012(10,11). 13. In the spaces provided, fill in the cover (depth) for the following residential underground installations (120/240 volt) a. Type NMWU with no other protection. 00 mm b. Type NMWU below the driveway. 900 mm c. Rigid conduit under the lawn. 450 mm d. Rigid 240-volt circuit conduit under the driveway. 600 mm e. Cable in poly pipe between the house and detached garage. 450 mm if NMWU; 300 mm if armoured cable. f. TECK cable under the lawn; circuit is 120 volts, 20 amperes, GFCI protected. 450 mm g. TECK cable with an approved plank covering under the driveway; the circuit is 240 volts AC. 450 mm h. Rigid non-metallic conduit, concrete-encased (50 mm); the circuit is 120 volts, 20 amperes, GFCI protected. 300 mm or 450 mm if under a driveway. i. Rigid conduit embedded in rock and grouted with concrete to the level of the rock surface. Trench to be 150 mm deep. 14. What rule of the CEC prohibits embedding type NMWU cable in concrete? Rule 12-512.

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Electrical Wiring: Residential, Seventh Canadian Edition

WHT

15. The following is a layout of the garage circuit. Using the suggested cable layout, make a complete wiring diagram of this circuit, using coloured pens or pencils to indicate conductor insulation colours.

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16. What type of motor is generally used for garage door openers? Split-phase motor. 17. How is the direction of a split-phase motor reversed? By reversing the direction of current in the starting winding in relation to the running winding, or by reversing the direction of current in the running winding in relation to the starting winding.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 25 Standby Power Systems Solutions to Review

Note: Refer to the CEC or the blueprints provided with this textbook when necessary. Where applicable, responses should be written in complete sentences. 1. The basic safety rule when working with electricity is to turn the power off. 2. What would be the logical location in which to run a portable generator? Outside in open air. 3. [Circle the correct answer.] The best advice to follow is to always use (listed)(cheapest)(smallest) equipment. That way you are assured that the product’s safety issues have been tested and verified by a recognized testing laboratory. After passing such tests, the product is then “listed.” 4. How would you define the term standby power? Standby power provides electrical power in the event of a power outage. 5. Describe in simple terms the three types of standby power systems. 1) The simplest standby power system is a motor/generator set that has a receptacle mounted on it. To operate in the event of a power outage, the gen set is placed outside in open air and started. An extension cord is plugged into the receptacle on the gen set to operate whatever electrical load is needed within the load limitations of the generator’s rating. 2) The next step up in standby power is a motor/generator, simple transfer switch, critical power (generator) panel, power inlet receptacle, and a power cord between the gen set and the power inlet. To operate in the event of a power outage, the gen set is placed outside in open air and manually started. A power cord is connected between the gen set and the power inlet receptacle. The transfer switch is manually switched over to standby power. This standby power position connects the critical (generator) panel, supplying only those branch circuits preselected as being critical to be energized during a power outage. 3) The top-of-the-line standby power system is one that has all components permanently installed. The gen-set automatically starts up in the event of a power outage, an automatic transfer switch transfers preselected loads to be supplied during the power outage and shuts down when the normal power is restored. 6. Briefly explain the function of a transfer switch. To provide a means of manually or automatically transferring to a standby generator in the event of a power outage.

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7. [Circle the correct answer.] When a transfer switch transfers to standby power, the electrical connection inside the switch a. maintains connection to the normal power supply as it makes connection to the standby power supply. b. breaks the connection to the normal power supply before it makes connection to the standby power supply. 8. [Circle the correct answer.] A typical transfer switch for residential application is a. three-pole, double-pole switch (TPDT). b. double-pole, double-throw switch (DPDT). c. single-pole, double-throw switch (SPDT). d. double-pole, single-throw switch (DPST). 9. The CEC requires that a disconnecting means be provided for standby power systems. In the case of portable gen sets, this might be as simple as pulling out the plug on the extension cord that is plugged into the receptacle on the gen set. For permanently installed standby power generators, this might be on the gen set and/or separately provided inside or outside the home.

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Electrical Wiring: Residential, Seventh Canadian Edition

Unit 26 Residential Utility-Interactive Solar Photovoltaic Systems Solutions to Review

Note: Refer to the CEC when necessary. Where applicable, responses should be written in complete sentences. 1.

Rule 64-200 contains most of the requirements for installation of photovoltaic systems.

2. CEC Rules 64-200(1) through 64-114(4) will apply to PV installations except as modified. 3. Name four electrical hazards associated with photovoltaic systems? a. Exposed conductors. b. Voltage up to 600 volts DC. c. Continuous currents. d. Low-fault currents. 4. Name five components of a utility-interactive photovoltaic system. a. Modules. b. Mounting racks. c. Combiner/transition boxes. d. Disconnects. e. Inverters. 5. Which conductor types are permitted to be installed exposed for array circuits? USE-2 and PV are conductor types permitted to be installed exposed for array circuits. 6. To size conductors and overcurrent devices for source circuits, you must multiply the module string short-circuit current by 1.56. 7. When is a metallic raceway required for photovoltaic source circuits? A metallic raceway is required for photovoltaic source circuits when the circuits enter the building before the disconnecting means. 8. Photovoltaic modules that also serve as an outer protective finish for a building are known as building integrated photovoltaic systems. 9. Grounding electrode system requirements for a utility-interactive photovoltaic system are found in which section of the CEC? Section 10 10. The two methods permitted for connection of a utility-interactive photovoltaic system to a service are known as supply side and load side.

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Electrical Wiring: Residential, Seventh Canadian Edition

REVIEW EXAMINATION This review examination covers the more important topics involved in residential wiring. The questions purposely do not refer to the actual residence described in the textbook. Rather, the review is aimed at those CEC rules, wiring diagrams, and related information that an electrician must know in order to be qualified to complete house wiring. REVIEW Part A - True or False 1. A branch circuit is all of the wiring from the final overcurrent devices protecting the circuit to the outlets. a. True b. False 2. The identified conductor may be white or green. a. True b. False 3. Fuses, switches, and breakers must be marked as to the portion of the installation they control. a. True b. False 4. A minimum working space of 1.25 m is required around electrical equipment. a. True b. False 5. All electrical equipment used in electrical installations must be approved by CSA or other approval agency. a. True b. False 6. Wire binding screws should be tightened to a torque of 1.4 newton metres. a. True b. False 7. The ampacity of a #10 AWG RW90-XPLE copper conductor in free air is 30 amperes. a. True b. False 8. 5-15R and 5-20R ampere receptacles installed to provide temporary power on construction sites are required to be GFCI-protected. a. True b. False

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9. When multiwire branch circuits are used, the continuity of the neutral must be independent of device connections. a. True b. False 10. Copper waste lines must be bonded to the system grounding conductor with a minimum #4 copper conductor. a. True b. False 11. A circuit breaker is an example of an overcurrent device. a. True b. False 12. Electric baseboard heaters must be supplied from a circuit used solely for the purpose of supplying heating equipment. a. True b. False 13. You are called in to replace a nongrounding-type receptacle with a grounding-type receptacle. The CEC allows you to replace this with a GFCI receptacle. a. True b. False 14. When replacing a plug fuse in the fusible disconnect for a 120/240-volt clothes dryer, a Type P or D plug fuse must be used. a. True b. False 15. The CEC requires that all panelboards have a circuit directory that legibly identifies the purpose and/or use of each circuit. a. True b. False 16. Pendant lamp fixtures are permitted to be installed in residential clothes closets. a. True b. False 17. Fixed gas, oil, or electric central heating equipment shall be supplied by a separate circuit. a. True b. False

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Electrical Wiring: Residential, Seventh Canadian Edition

18. If a raceway installation is such that it is impossible to pull in the conductors, the CEC allows part of the raceway to be removed so that the conductors can be pulled into the partially installed raceway system, then slide the remaining portion of the raceway over the conductors to complete the installation. This will save a junction box. a. True b. False 19. All interior metal gas piping shall be bonded to ground. a. True b. False 20. Submersible water pumps shall be bonded to ground. a. True b. False 21. Self-generating gas fireplaces may be operated without an outside power source. a. True b. False 22. Electric baseboard heaters should not be installed beneath a receptacle outlet. a. True b. False 23. A switch that is marked “AC only” may be used on DC circuits. a. True b. False 24. Fluorescent lamps can be dimmed if special dimming ballasts or dimmers are provided. Is this statement: a. True b. False 25. The CEC has 10 general sections. The remaining sections are supplementary or amending sections. a. True b. False

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Part B – Multiple Choice 1. When a pair of wire connectors are used inside an outlet box, the number of conductors allowed in the box must be reduced by: a. one conductor. b. two conductors. c. remains the same. d. six conductors. 2. A dashed line running between various switches and outlets indicates: a. the routing for the cables. b. that the switch and outlets are grounded. c. that the outlet is controlled by the switch. d. that the outlet is a switched receptacle. 3. Receptacle outlets must be installed so that no point along the floor line in a finished room is more than: a. 1.8 m from a receptacle. b. 900 mm from a receptacle. c. 2.6 m from a receptacle. d. 4.5 m from a receptacle. 4. Receptacle outlets must be installed so that no point along the wall behind the kitchen counter is more than: a. 1.8 m from a receptacle. b. 900 mm from a receptacle. c. 3.6 m from a receptacle. d. 4.5 m from a receptacle. 5. Receptacle outlets must be installed so that no point in a hallway measured by the shortest path is more than: a. 1.8 m from a receptacle. b. 900 mm from a receptacle. c. 3.6 m from a receptacle. d. 4.5 m from a receptacle. 6. When the word “shall” appears in the Canadian Electrical Code, it means: a. it must be done. b. it may be done. c. it is possible to do it. d. it does not have to be done.

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Electrical Wiring: Residential, Seventh Canadian Edition

7. Non-metallic-sheathed cable must be stapled or supported at not more than: a. 300 mm from a box. b. 900 mm from a box. c. 150 mm from a box. d. 1 m from a box. 8. Which of the following cables may be installed outdoors exposed to the weather: a. AC90 b. NMD90 c. NMWU d. LVT 9. When NMSC cable is run through joists, studs, and rafters, the minimum distance between the front edge of the joist or stud and the cable is: a. 38 mm. b. 32 mm. c. 150 mm. d. 12.5 mm. 10. In general, the loading on any continuous load circuit or feeder shall not exceed ___% of the rating of that circuit. a. 75 b. 80 c. 50 d. 125 11. Boxes installed in combustible walls must be installed: a. flush with the finished surface. b. protruding a minimum of 6 mm from the surface. c. recessed 6 mm maximum from the finished surface. d. not more than 9 mm recessed from the finished surface. 12. In order to provide access to junction boxes, a vertical space of _____ is required. a. 1.2 m b. 900 mm c. 450 mm d. 300 mm 13. The maximum number of #14 R90-XLPE wires that are allowed in a 4” x 1½” octagon box that contains three wire connectors and one fixture stud is: a. 10. b. 8. c. 7. d. 6.

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14. A point in a wiring system where current is taken to supply equipment which uses electrical energy is called: a. a switch. b. a junction box. c. an outlet. d. a branch circuit. 15. The maximum number of outlets on any two-wire branch circuit is: a. 10. b. 12. c. 16 on a 20-ampere branch circuit. d. any number, if the current does not exceed 80% where the load is not known. 16. The minimum distance that consumer’s service conductors should extend beyond the service head is: a. 300 mm. b. 600 mm. c. 750 mm. d. 1.2 m. 17. If a 65-m run of 1¼” PVC conduit is subjected to temperature ranging from –40°C to +40°C, how many expansion joints should be installed in the conduit run if each section can expand 80 mm? a. 2 b. 3 c. 4 d. 5 18. The maximum number of conductors allowed in one conduit is: a. 100. b. 200. c. 250. d. There is no maximum as long as Table 8 fill is not exceeded. 19. Which of the following is not permitted: a. a recessed clock outlet connected to the refrigerator receptacle circuit b. the utility room and laundry rooms on separate circuits c. outdoor receptacles connected to bedroom circuits d. adjacent receptacles on a kitchen counter on separate circuits

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Electrical Wiring: Residential, Seventh Canadian Edition

20. Insulating bushings must be used on rigid metal conduit to protect the insulation on conductors sized at _________ and larger. a. #6 AWG b. #8 AWG c. #4 AWG d. #3 AWG 21. An electric heater is rated at 2760 watts, 240 volts. What current will it draw? a. 23 amperes b. 11.5 amperes c. 27.6 amperes d. 15.2 amperes 22. What is the maximum load permitted to be connected to a 20-ampere 80% rated circuit? a. 20 amperes b. 12 amperes c. 16 amperes d. 18 amperes 23. In new residences, GFCI protection must be provided for receptacles in: a. bathrooms. b. basements. c. outdoors at grade level. d. bathrooms and outdoors at grade level. 24. When four current-carrying conductors are installed in one conduit, the ampacities of these conductors as found in Table 2 must be reduced to: a. 90%. b. 80%. c. 70%. d. 60%. 25. A dual-element, time-delay fuse installed as the running protection for a motor is generally sized at ______% of the full-load rating of the motor in amperes. a. 125 b. 80 c. 175 d. 300

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26. Chime transformers are generally classified by CSA for use in Class 2 extra-lowvoltage systems. These transformers are limited to a maximum output of: a. 1000 VA b. 2500 VA c. 100 VA d. 10 amperes 27. What is the current rating of a 240-volt, 2500-watt electric heater? a. 11.36 amperes b. 20.8 amperes c. 10.4 amperes d. 5.9 amperes 28. To reduce corrosion in water heaters, what type of rods are installed by the manufacturer of the water heater? a. copper b. zinc c. magnesium d. PVC 29. The humidistat element that is sensitive to changes in humidity is usually made of: a. silver. b. nylon. c. bimetal. d. Teflon. 30. What is the current rating of an electric water heater having one 1500-watt and one 2000-watt element connected so that both elements can be energized at the same time? The voltage rating is 236 volts. a. 8.47 amperes b. 11.86 amperes c. 14.8 amperes d. 17. 183 amperes 31. What is the minimum size of copper TWN75 wire that would be installed for the electric water heater in question 30? a. #14 AWG b. #12 AWG c. #10 AWG d. # 8 AWG

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Electrical Wiring: Residential, Seventh Canadian Edition

32. What size overcurrent device would be installed for the water heater in question 30? a. 15 amperes b. 20 amperes c. 25 amperes d. 30 amperes 33. What is the current draw for a 240-volt, 2500-watt electric heater when connected to a 120-volt circuit? a. 20.8 amperes b. 10.4 amperes c. 5.2 amperes d. 2.84 amperes 34. What is the wattage output of a 240-volt, 2500-watt electric heater when connected to a 120-volt circuit? a. 1250 watts b. 20.8 watts c. 625 watts d. 780 watts 35. For safety reasons, a general requirement of the CEC is that the disconnecting means must be _______________ of the equipment it is to disconnect. a. out of sight b. within sight c. behind d. below 36. Self-generating gas burner systems develop their power through a device called a: a. thermistor. b. thermocouple. c. RTD. d. bimetallic strip. 37. The CEC requires residential service-drop conductors to have a clearance of not less than _____ over the driveway to a residential garage. a. 4.0 m b. 4.5 m c. 5.0 m d. 3.5 m 38. Service conductors must clear windows and doors by not less than ___________. a. 2.0 m b. 1.75 m c. 1.5 m d. 1000 mm

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39. The minimum size service permitted for a single dwelling with a floor area of 80 m2 (excluding the basement) is _______________. a. 30 amperes b. 60 amperes c. 100 amperes d. 200 amperes 40. What action must be taken to prevent condensation from entering a service through the service raceway due to changes in temperature? a. Terminate the conduit on the top of the panel. b. Effectively drain and seal the raceway. c. Install an expansion joint in the raceway. d. Condensation is never a problem if fittings are properly installed. 41. When installing a 4-11/16 box for a freestanding electric range, the box should be mounted so that it is centred in the space for the range and at a height that does not exceed ______ to centre. a. 50 mm b. 70 mm c. 130 mm d. 150 mm Questions 42 to 47 pertain to the following calculations. Use the 2015 CEC to calculate the minimum ampacity of service for a single dwelling having the following: 200 m2 of living area One 12 kW 120/240-volt range One 4 kW 120/240-volt clothes dryer One 3 kW hot water heater One 8 kW pool heater 42. The total demand is: a. 34 kW b. 25 kW c. 22.75 kW d. 18.75 kW 43. The ampacity of service required is: a. 80 amperes. b. 100 amperes. c. 125 amperes. d. 200 amperes.

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Electrical Wiring: Residential, Seventh Canadian Edition

44. The minimum size of service conductors using copper RW90 XLPE is: a. #6 AWG. b. #3 AWG. c. #2 AWG. d. #2/0 AWG. 45. The minimum size of service raceway for the service conductors is: a. 27 mm. b. 35 mm. c. 41 mm. d. 53 mm. 46. The minimum size grounding conductor for this service (if it is run open) is: a. #10 Cu. b. #8 Cu. c. #6 Cu. d. #4 Cu. 47. The minimum number of circuits in the panel is: a. 16 circuits. b. 24 circuits. c. 30 circuits. d. 40 circuits. 48. Typical low-voltage remote control wiring systems operate at approximately ________ volts. a. 12 b. 16 c. 24 d. 36 49. What is the maximum distance that a disconnect may be located away from an air conditioner? a. 1.5 m b. 3 m c. 6 m d. 9 m 50. The closest distance that a receptacle may be installed to the inside edge of a swimming pool is: a. 750 mm. b. 1.0 m. c. 1.5 m. d. 2.0 m.

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51. If a receptacle is located within 3 m of the inside edge of a swimming pool, the receptacle must be: a. GFCI-protected. b. a three-wire, grounding type. c. a two-wire, isolation type. d. Receptacles are not permitted within 3 m of a pool. 52. A receptacle for a cord-connected hydromassage bathtub must be mounted at a height of not less than _____ above the finished floor. a. 100 mm b. 150 mm c. 250 mm d. 300 mm 53. A four-way switch is connected using two pieces of NMD90. Each cable has four solid copper conductors, three are insulated (one red, one black, and one white) and one is bare. This is referred to in the electrical trade as a: a. single conductor cable. b. two pair cable. c. three conductor cable. d. four conductor cable. 54. For a wiring device (switch or receptacle) that is mounted on a strap, the number of conductors to be deducted from the maximum permitted for a box listed in Table 23 of the CEC is: a. one. b. two. c. three. d. No deduction. 55. To assure adequate conductor length in all outlet and device boxes, the CEC requires that at least ______ of free conductor be provided. a. 100 mm b. 150 mm c. 300 mm d. 450 mm 56. In “series rated” circuit-breaker installations, if a fault occurs on the load side of a branch circuit breaker that exceeds the interrupting rating of the branch breaker: a. the branch circuit breaker and the main breaker will both trip off, shutting off all electrical power. b. only the branch circuit breaker will trip off. c. only the main breaker will trip off, shutting all power off.

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Electrical Wiring: Residential, Seventh Canadian Edition

57. For a single-dwelling residential driveway, the minimum depth for buried NMWU cable less than 750 volts is: a. 450 mm. b. 600 mm. c. 750 mm. d. 900 mm. 58. According to Table 13 of the CEC and Rule 14-104, if a #6 TW75 copper conductor was installed in conduit, the maximum permissible fuse is: a. 50 amperes b. 60 amperes. c. 65 amperes. d. 70 amperes. 59. Non-metallic-sheathed cable and armoured cable must be strapped or supported at not more than __________ between supports. a. 300 mm b. 900 mm c. 1.5 m d. 1.75 m 60. Wet-niche lighting fixtures shall not be submerged to a depth of not more than: a. b. c. d.

150 mm. 300 mm. 450 mm. 600 mm.

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Part C - Short Answer Questions 1. What is the minimum size of conduit permitted for each of the following insulated conductors? a. four TW75 Nylon #14 AWG ___________ b. five RW75 XLPE 1000-volt without a jacket#12 AWG

___________

c. three R90 XLPE 600-volt without a jacket #10 AWG

___________

d. four R90XLPE 600-volt with jacket #8 AWG

___________

e.

___________

three TWU75 #3/O AWG

2. Determine the EMT size required for the following conductors. Show all calculations. Three TW75 #3/O Two TW75 #10 3. The grounding of tools and appliances is a basic requirement. An exception is made when the tool or appliance is provided with ___________ insulation. 4. A threaded conduit body is considered adequately supported when _________________________________________________________________. 5. Type NMWU cable used as an underground residential branch circuit not over 240 volts must be buried at least (a) _______ mm below grade; it may be buried only (b) ______ mm if it is protected by a raceway. The installation is not under a driveway. 6. Why are electrical systems grounded? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 7. Why are electrical equipment and conduits bonded together and grounded? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 8. Joining together all water pipes, gas pipes, electrical equipment, and all other metal objects to assure continuity between them is called _________ by the CEC.

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Electrical Wiring: Residential, Seventh Canadian Edition

9. Care must be used when routing cables and connecting the conductors to ensure that all of the conductors of the circuit are run through the same metal hole in a box. If this is not done, there will be __________ heating in the metal box. The heat may melt or otherwise harm the insulation on the conductors. 10. Is it permissible to use the screw terminals of a receptacle to splice the neutral conductor of a three-wire circuit? Explain the answer. __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ 11. A residential-type ground-fault circuit interrupter may be an integral part of the circuit breaker feeding the circuit or it may be an integral part of the receptacle outlet. In either case, the GFCI will trip at ground currents that exceed _________. 12. A bonding conductor (shall) (may) be connected to the green hexagonal terminal of a receptacle outlet. Underline the correct answer. 13. An electric clothes dryer has a nameplate rating of 5200 watts at 240 volts. Calculate the current rating of this clothes dryer and determine the proper size of type R90 copper conductors that can be used. The terminals on the dryer are marked 75°C. 14. The nameplate of a free-standing 240-volt range is 16 kW. Calculate the current rating of this range and the required sizes of the hot conductor and the neutral conductor using NMD90. The terminals of the range are marked 75°C. 15. For residential installations, two types of lead-in television cables are commonly used. These are (a) ________-ohm cable and (b) _________-ohm coaxial cable. 16. When more than one chime is to operate from the same pushbuttons, the proper transformer size is selected by adding the __________ of the individual chimes. 17. List the interrupting ratings for the following devices: a. Standard types of residential circuit breakers. ___________ amperes b. Class H ___________ amperes c. HRC Type J ___________ amperes 18. What minimum sizes of RW90 XLPE copper “hot” conductors are required for the following residential services? a. 100-ampere service # ____________ AWG b. 200-ampere service # ____________ AWG c. 400-ampere service # ____________ kcmil

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19. What is the minimum size of grounding conductor required for each of the services? a. 100-ampere service # ____________ AWG b. 200-ampere service # ____________ AWG c. 400-ampere service # ____________ AWG 20. Service grounding conductors that run from the main service switch to the water main may or may not require mechanical protection. Do the following conductors require protection? Explain. a. #8 _________________________________________________________ b. #6 _________________________________________________________ c. #4 _________________________________________________________ 21. What letters on the label of an incandescent recessed fixture indicate that it may be completely buried in insulation? ______________________ 22. What is the maximum weight of a lighting fixture that may be hung directly from a ceiling outlet box? _________________ 23. If a decorative hanging fixture is installed in a bathroom within 2.5 m vertically or 1.5 m horizontally of the tub or sink, how shall the light be controlled? __________________________________________________________________ 24. May Class 2 control-circuit wires be run in the same raceway as the power conductors to feed an air-conditioning unit outside of a house? ___________ Quote the rule from the CEC: _____________ 25. When counting wires in a conduit for derating purposes, indicate whether the statement is true or false. a. Equipment bonding contractors are counted. __________ b. All identified conductors are counted. __________ c. All neutrals are counted. __________ d. Control circuit conductors are not counted. __________ 26. What section of the CEC covers remote control, signalling, and power-limited circuits? ___________________________________ 27. Time-delay fuses do not open when harmless overloads occur. These fuses will hold (a) ___________ % of their rating in amperes for up to (b) ___________ seconds.

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Electrical Wiring: Residential, Seventh Canadian Edition

28. A 120-volt fluorescent ballast supplies two 40-watt fluorescent lamps. The label states “60% power factor.” Calculate the line current draw of this ballast. _______________________________________________________________ 29. The only time when kVA and kW are the same is when the load is operating at ______ power factor.

30. When installing a two-pair telephone cable having two pairs, the tip conductor of the red and green pair is the _____________conductor.

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Part D - Questions with Diagrams 1. Show the number of conductors in each cable in the drawing below.

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Electrical Wiring: Residential, Seventh Canadian Edition

2. Complete the line-voltage and low-voltage connections in the following diagram. Use coloured pencils to indicate conductors. Show extra-low-voltage connections with a dot. Switch No. 1 controls lamps A and C, switch No. 2 controls lamp B, and switch No. 3 controls the bottom of each receptacle. The top of each receptacle is to be hot at all times. The line-voltage wiring is in armoured cable.

A

B

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C

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3. Complete the wiring diagram, connecting feedthrough GFCI 1 to also protect receptacle 1, both to be supplied by Circuit A1. Connect feedthrough GFCI 2 to also protect receptacle 2, both to be supplied by Circuit A2. Use coloured pencils or coloured markers to show proper colour.

4. Complete the connections in the following arrangement so that both ceiling light outlets are controlled from the single-pole switch. Assume the installation is in cable.

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Electrical Wiring: Residential, Seventh Canadian Edition

5. Identify the terminals on the receptacle below.

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Electrical Wiring: Residential, Seventh Canadian Edition

ANSWERS TO REVIEW EXAMINATION Part A - True or False 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.

a (TRUE) b (FALSE) a (TRUE) b (FALSE) a (TRUE) a (TRUE) b (FALSE) a (TRUE) a (TRUE) b (FALSE) a (TRUE) a (TRUE) a (TRUE) a (TRUE) a (TRUE) b (FALSE) a (TRUE) b (FALSE) a (TRUE) a (TRUE) a (TRUE) a (TRUE) b (FALSE) a (TRUE) a (TRUE)

Definitions 4-030(1) 2-100 2-308, Table 56 2-024(1) Appendix D6 Table 1 76-016 4-036(4) 10-406(3) Definitions 62-110 (1)(a) 26-700 (8)(a) 14-610 / 14-200 2-100 30-204(2) 26-806(1) 12-938 10-406(4) 26-954(d) 26-712(a), Appendix B 2-100(1)(f) Preface (General Arrangement)

Part B - Multiple Choice 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

a c a b d a a c b b a b b

12-3034(1)(a) 26-712(a) 26-712(d)(iii) 26-712(f) 12-510(1)(a) Table 19 12-516(1) 8-104(5), Appendix B 12-3016(1) 12-3014(2) 12-3034(2)

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14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33.

c b c b b c b b c d b a c c c b c b a c

34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57.

c b b a d c b c c b b b c c c b c a d c b b a d

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Definitions 8-304(1) 6-302(3) 12-1118; i.e., 65 x 80 x 0.0520 = 270 mm; therefore, 3 expansion joints. 12-910(5) 26-720 to 724 12-906(2)(a) I=P/E; i.e., 2760W/240V = 11.5A 8-104(6)(a) 26-700(11) Table 5C, 4-004(1)(c) 28-106(1) 16-200 I=P/E; i.e., 2500W/240V = 10.4A

I=P/E; i.e., 3500W/236V = 14.8A Table 2 (Conductor draws 20A), 8-104(6) Table 13 I=P/E; i.e., 2500W/240V = 10.41667A R=E/I; i.e., R = 240V/10.417A = 23.04ohms I @ new V =120/23.04 = 5.208A P=I*E; i.e., 120V x 5.208A= 625W 2-310(2) 6-112(2)(b) 6-112(3) 8-200(1)(b)(i) 6-312(1) 26-744(6)(a) 8-200 8-200 Table 2 Table 6A 10-812(a) 8-108(1)(c)(i) 16-200(1)(b) 28-604(5) 68-064(1) 68-064(2) 68-306(1)(a) 12-3034(2)(c) 12-3000(6) 14-014 Table 53

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Electrical Wiring: Residential, Seventh Canadian Edition

58. 59. 60.

d c d

Table 2, TW75 handles 65A, then Table 13 12-510(1) 68-066(1)(b)

Part C - Short Answer Questions 1. a. 16 mm b. 21 mm a. T6(J) b. T6(B)

c. 16 mm c. T6(A)

d. 27 mm d. T6(C)

e. 53 mm e.T6(D)

2. Cross-sectional area of conductors from Table 10: Three #3/0 TW75 = 3 x 201 = 603 Two #10 TW75 = 2 x 15.67 = 31.34 Total 634.34 mm2 Referring to Table 9I @ 40% column = 53 mm conduit. 3. The grounding of tools and appliances is a basic requirement. An exception is made when the tool or appliance is provided with double insulation. 4. A threaded conduit body is considered adequately supported when attaching to a firmly secured exposed raceway. Rule 12-3012(2). 5. Type NMWU cable used as an underground residential branch circuit not over 240 volts must be buried at least (a) 600 mm below grade; it may be buried only (b) 450 mm if it is protected by a raceway. The installation is not under a driveway. Rule 12-012, Table 53. 6. Why are electrical systems grounded? To keep the voltage spikes to a minimum and stabilize the voltage. 7. Why are electrical equipment and conduits bonded together and grounded? To provide a low-impedance path so that overcurrent devices will operate quickly should a hot conductor come in contact with non-current-carrying metal parts of the electrical system. To keep the voltage to ground on the equipment to a minimum, thus reducing the shock hazard. 8. Joining together all water pipes, gas pipes, electrical equipment, and all other metal objects to assure continuity between them is called bonding by the CEC. 9. Care must be used when routing cables and connecting the conductors to ensure that all of the conductors of the circuit are run through the same metal hole in a box. If this is not done, there will be induction heating in the metal box. The heat may melt or otherwise harm the insulation on the conductors.

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A-3

10. Is it permissible to use the screw terminals of a receptacle to splice the neutral conductor of a three-wire circuit? Explain the answer. No. An open neutral of a three-wire circuit could subject any device plugged into the receptacle to a higher than normal voltage. 11. A residential-type ground-fault circuit interrupter may be an integral part of the circuit breaker feeding the circuit or it may be an integral part of the receptacle outlet. In either case, the GFCI will trip at ground currents that exceed 6mA. 12. A bonding conductor (shall) (may) be connected to the green hexagonal terminal of a receptacle outlet. Underline the correct answer. 13. An electric clothes dryer has a nameplate rating of 5200 watts at 240 volts. Calculate the current rating of this clothes dryer and determine the proper size of type R90 copper conductors that can be used. The terminals on the dryer are marked 75°C. Current rating: I = P/E = 5200/240 = 21.66 amperes Table 2 75°C column #12 would be 25x.8=20A No good Use #10 remember to derate at 80% (35 x 0.80 = 28 amperes) 14. The nameplate of a free-standing 240-volt range is 16 kW. Calculate the current rating of this range and the required sizes of the hot conductor and the neutral conductor using NMD90. The terminals of the range are marked 75°C. Rule 8-300(1) First 12 kW = 8.0 kW Next 4 kW @ 40% = 1.6 kW Total demand watts = 9.6 kW I=P/E 9600/240 = 40 amperes Therefore, use #8 for terminal rating 75°C. 50 x .8= 40 amperes. 15. For residential installations, two types of lead-in television cables are commonly used. These are (a) 300-ohm cable and (b) 75-ohm coaxial cable. 16. When more than one chime is to operate from the same pushbuttons, the proper transformer size is selected by adding the volt-amps of the individual chimes. 17. List the interrupting ratings for the following devices: a. Standard types of residential circuit breakers. 10 000 amperes b. Class H 10 000 amperes c. HRC Type J 200 000 amperes, 300 000-ampere fuses are available. See Appendix B, Rule 14-212

A-4

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Electrical Wiring: Residential, Seventh Canadian Edition

18. What minimum sizes of RW90 XLPE copper “hot” conductors are required for the following residential services? 100-ampere service # 3 AWG 200-ampere service #3/0 AWG 400-ampere service #500 kcmil 19. What is the minimum size of grounding conductor required for each of the services? 100-ampere service #8 (#6 if run open) AWG 200-ampere service #6 AWG 400-ampere service #4 AWG See Table 16A. 20. Service grounding conductors that run from the main service switch to the water main may or may not require mechanical protection. Do the following conductors require protection? Explain. a. #8 Yes. 10-806(3). b. #6 No, if not exposed to mechanical injury. 10-806(2). c. #4 No, if not exposed to mechanical injury. 10-806(2). 21. What letters on the label of an incandescent recessed fixture indicate that it may be completely buried in insulation? IC 22. What is the maximum weight of a lighting fixture that may be hung directly from a ceiling outlet box? 23 kg. 30-302(4). 23. If a decorative hanging fixture is installed in a bathroom within 2.5 m vertically or 1.5 m horizontally of the tub or sink, how shall the light be controlled? Wall switch located 1 m from tub (may be 500 mm if GFCI-protected). 24. May Class 2 control-circuit wires be run in the same raceway as the power conductors to feed an air-conditioning unit outside of a house? No. Quote the rule from the CEC: Rule 16-212. 25. When counting wires in a conduit for derating purposes, indicate whether the statement is true or false. a. Bonding conductors are counted. F b. All identified conductors are counted. T c. All neutrals are counted. F d. Control circuit conductors are not counted. T Rule 12-3034 assist. 26. What section of the CEC covers remote control, signalling, and power-limited circuits? Section 16

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A-5

27. Time-delay fuses do not open when harmless overloads occur. These fuses will hold (a) 500% of their rating in amperes for up to (b) 10 seconds. 28. A 120-volt fluorescent ballast supplies two 40-watt fluorescent lamps. The label states “60% power factor.” Calculate the line current draw of this ballast. I = P/E x pf = 80/(120 x 0.60) = 1.11 amperes 29. The only time when kVA and kW are the same is when the load is operating at unity power factor. 30. When installing a two-pair telephone cable having two pairs, the tip conductor of the red and green pair is the green conductor.

A-6

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Electrical Wiring: Residential, Seventh Canadian Edition

Part D - Questions with Diagrams 1. Show the number of conductors in each cable in the drawing below.

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A-7

2. Complete the line-voltage and low-voltage connections in the following diagram. Use coloured pencils to indicate conductors. Show extra-low-voltage connections with a dot. Switch No. 1 controls lamps A and C, switch No. 2 controls lamp B, and switch No. 3 controls the bottom of each receptacle. The top of each receptacle is to be hot at all times. The line-voltage wiring is in armoured cable.

A

A-8

B

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C

Electrical Wiring: Residential, Seventh Canadian Edition

3. Complete the wiring diagram, connecting feedthrough GFCI 1 to also protect receptacle 1, both to be supplied by Circuit A1. Connect feedthrough GFCI 2 to also protect receptacle 2, both to be supplied by Circuit A2. Use coloured pencils or coloured markers to show proper colour. Instructor can determine if answer submitted by student is satisfactory.

4. Complete the connections in the following arrangement so that both ceiling light outlets are controlled from the single-pole switch. Assume the installation is in cable.

Instructor can determine if answer submitted by student is satisfactory. Copyright © 2016 by Nelson Education Ltd.

A-9

5. Identify the terminals on the receptacle below. Bonding Terminal G X

Y

L2 Hot Conductor

L1 Hot Conductor

W Neutral Terminal

A-10

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