This Old House - Do It Youself Electrical Tips

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This Old House Do-It-Yourself Electrical Tips

Is Old Wiring Safe? 10 Wiring Problems Solved Electrical Upgrades ●

Installing a Floodlight

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Adding Outlets To a Garage

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Replacing an Outlet with a GFCI Circuit

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Replacing Ungrounded Outlets

Is Old Wiring Safe? It's not just the nation's power grid that's antiquated. The wiring inside many houses is also out of date, straining to supply our ever-growing collection of electricity-hungry appliances, lighting, and electronics. The circuits in many older homes weren't designed to power the many gadgets of modern life. The signs of strain may be obvious — a tangle of extension cords and power strips sprouting from a single outlet — or lurking unseen behind walls, ceilings, and cover plates. Today's standard household wiring is a plastic-sheathed, insulated three-wire cable, universally known by the trade name Romex. But the vintage copper wiring in many older houses works just as well as the new stuff, as long as it's in good condition and hasn't been altered in a way that violates code. Here are some wiring systems you'll find in older homes. Knob and Tube Knob and tube was the earliest residential wiring system has a cloth-covered hot wire and a neutral wire, which run parallel about a foot apart. Ceramic knobs anchor the wires to the house framing; ceramic tubes are used where wires cross or penetrate framing. Danger: Knob and tube wiring may be covered with building insulation, which causes overheating. Caveats: Cannot be grounded or spliced into a grounded circuit. Its soldered connections may melt if too much current flows through them. Rewire or disconnect any circuits covered with building insulation; it causes this wiring to overheat.

Armored Cable (Bx)

Armored cable is the successor to knob and tube. A flexible steel sheath covers hot and neutral wires, which are insulated with cloth-covered rubber. The sheath provides a ground, so grounded receptacles are easy to retrofit. Danger: Armored cable insulation degrades over time, as shown above, or if too much current is allowed to flow through the circuit. Caveats: Sheath must be anchored securely to a metal outlet box. Check condition of insulation every five years or so; it

Two-wire plastic-sheathed cable

Two-wire plastic-sheathed cable was commonly used after armor cable and before Romex became the standard. Danger: Grounded receptacles cannot be retrofitted to two-wire plastic-sheathed cables. Caveats: Plastic is easily damaged. Grounded receptacles cannot be retrofitted to this wire.

Protecting the Box Fuse boxes are less common these days than circuit breaker panels, but they work just fine — unless someone installs fuses with a higher amperage than the wires can safely handle. That can cause the wires to overheat, damaging their protective insulation and increasing the risk of fire. Once the insulation has been damaged, the danger remains even if the offending fuse is replaced with one that's the proper amperage. To fix it, the old circuit must be rewired. Some wiring problems are just inconveniences. But others can pose serious fire or electrocution hazards. If you're buying a house (especially one that's more than 50 years old), or if you've never had your wiring inspected, it's a good idea to hire a licensed electrician to give your home a thorough going-over. "He'll look at the insulation on the wires to see if it's dried out and fraying, he'll look for corrosion in the service panel, and he'll look to see if a previous owner did anything unsafe," Gallant says. After that, he recommends getting a quick follow-up inspection every five years. Don't be alarmed if the inspection turns up code violations. Each time the electrical code is revised, old wiring is "grandfathered," on the assumption it was installed correctly. Code only requires you to update wiring in rooms being gut-renovated. To help you assess the state of your own electrical system, we've asked Gallant to identify the 10 most common wiring problems he sees, the dangers they pose, and his recommended solutions. Remember: Anytime you work with wiring, be sure to turn off the circuit at the main breaker panel.

How GFCI Receptacles Keep You Safe

A ground fault happens whenever electricity escapes the confines of the wiring in an appliance, light fixture, or power tool and takes a shortcut to the ground. When that short cut is through a human, the results can be deadly. About 200 people in the U.S. alone die of ground faults each year, accounting for two-thirds of all electrocutions occurring in homes. To prevent such accidents, Charles Dalziel, a professor of electrical engineering at the University of California, invented the ground-fault circuit interrupter (GFCI), in 1961. Most of the time, his invention does nothing; it just monitors the difference in the current flowing into and out of a tool or appliance. But when that difference exceeds 5 milliamps, an indication that a ground fault may be occurring, the GFCI shuts off the flow in an instant — as little as .025 second. GFCIs are required by the National Electric Code in all new kitchens, bathrooms, crawl spaces, unfinished basements, and most outdoor receptacles. Owners of older houses can retrofit $10 GFCI receptacles at those locations or have GFCI breaker switches (which run as much as $108 for 50-amp models) mounted in the main breaker panel. Portable GFCI adapters, which plug into regular wall receptacles, are available for about $40. The great thing about GFCIs is that they protect you whether or not your wiring is grounded. Because lightning and other power surges can damage a GFCIs delicate circuitry at any time, perform the following monthly test: Plug in a light fixture and turn it on. Then push the device's test button. If the light stays on, the GFCI needs to be replaced.

10 Wiring Problems Solved PROBLEM #1 Overlamping is when a light fixture has a bulb with a higher wattage than the fixture is designed for What it means: A light fixture has a bulb with a higher wattage than the fixture is designed for. Code violation? Yes. Danger level: High. The bulb's intense heat can scorch or melt the socket and insulation on the fixture's wires, which increases the risk of arcing — sparks that jump through the air from one wire to another — a chief cause of electrical fires. The damage to socket and wires remains even after the bulb has been removed. Solution: Stay within the wattage limit listed on all light fixtures made since 1985. For older, unmarked fixtures, use only 60-watt bulbs or smaller. PROBLEM #2 Uncovered junction boxes increase the risk of wire damage and shock What it means: Because a junction box houses the splices where wires are connected to one another, a person could inadvertently damage the wires or get a shock. Code violation? Yes. Danger level: Minimal, as long as wires aren't within reach. Solution: Spend a few cents to buy a new cover and install it with the screws provided. PROBLEM #3 Lights flicker when it's windy because frayed wiring causes a short whenever the cables move What it means: Frayed wiring in the weatherhead (the outdoor fitting where overhead cables from the power line come into the house) is causing a short whenever the cables move. Code violation? No. Danger level: High. Aside from the annoyance, the frayed wiring can arc and start a fire. Solution: Contact the electric utility, which may replace the weatherhead at no charge.

PROBLEM #4 Not enough outlets means you're likely to rely on extension cords and power strips What it means: Heavy reliance on extension cords and power strips. Code violation? No; grandfathered in. (Today's codes require receptacles within 4 feet of a doorway and every 12 feet thereafter.) Danger level: Minimal, as long as you use heavy-duty extension cords, 14-gauge or thicker. (The thicker the wire, the lower the gauge number.) Undersize extension cords (16-gauge or smaller) can overheat and ignite a fire if loads are too heavy. Solution: Add more outlets. Expect to pay an electrician about $100 per first-floor outlet and double that for second-floor work. (There will likely be a minimum charge.) This work requires cutting holes in walls and ceilings to snake the wires. Some electricians will patch the holes; others leave the patching to you.

PROBLEM #5 GFCIs shut down circuits in 4 milliseconds to prevent fatal shock What it means: Increased risk of electrocution in wet areas, such as baths and kitchens. GFCIs (ground-fault circuit interrupters) shut down circuits in 4 milliseconds, before current can cause a deadly shock. Code violation? No; grandfathered in. (Codes today require GFCIs within 4 feet of any sink and on all garage, basement, and outdoor outlets.) Danger level: High. Solution: Replace old receptacles with GFCIs (about $12 each). This is a simple job that many homeowners do themselves. Electricians charge about $20 per outlet. (There will likely be a minimum job charge.) Note: As an alternative, GFCI breakers ($25) can be installed on the main panel. But then every time one trips, you have to go down to the basement to reset it.

PROBLEM #6 Overwired panels contain more circuits than they are rated to handle What it means: The panel contains more circuits than it's rated to handle, because too many single-pole breakers (one circuit) have been replaced with tandem breakers (two circuits) in one slot. (Tandem breakers aren't the same as high-amp double-pole breakers, which take up two slots with one circuit.) A label on each panel specifies how many circuits the panel can accommodate. Code violation? Yes. Danger level: Minimal. It may become an issue when the house is being sold and an inspector looks inside the panel. Solution: Add a subpanel with a few extra slots ($250), or, if you're planning major home improvements, replace the existing panel with a larger model ($500 to $800).

PROBLEM #7 Popular in the 1960s and '70s, unsafe aluminum wiring is a cheap substitue for copper What it means: You have a type of wiring, used in the 1960s and '70s as a cheap substitute for copper, that is no longer considered safe. Code violation? No; grandfathered in. Danger level: High. Aluminum corrodes when in contact with copper, so connections loosen, which can lead to arcing and fires. Solution: Retrofit a dielectric wire nut approved for aluminum wire (a pair sells for less than $1) onto each copper/aluminum connection in light fixtures. These nuts have a special grease that stops corrosion while maintaining conductivity. Make sure any replacement switches and receptacles are labeled ALcompatible. PROBLEM #8 Backstabbed wires are more likely to come loose What it means: On newer switches and receptacles, wires pushed in the back are more likely to come loose than those anchored around screw terminals. Code violation? No. The practice is allowed, even for new construction. Danger level: It depends. At a minimum, loose wires can cause a receptacle or switch to stop working. In the worst case, they can start a fire. Solution: Check for backstabbed connections by removing a switch or receptacle from its outlet box. Release the wires and attach them to the appropriate screw terminals on the receptacle.

PROBLEM #9 Undergrounded (2-pronged) receptacles means your home has no way to safely conduct stray current What it means: Your house's wiring has no way to safely conduct any stray current that escapes the confines of the wires. Code violation? No; grandfathered in. (Today's code requires grounded circuits and receptacles.) Danger level: Minimal, as long as you don't use an adapter to fit a three-prong plug into a two-prong receptacle. Doing so could destroy the device you're plugging in, and increase the chance of electrocution. Solution: Replace two-prong receptacles with properly grounded three-prong ones, if wiring allows it (see . Also, test all existing three-prong receptacles with a GFCI circuit tester to make sure they're grounded. Rewire any that aren't. PROBLEM #10 Plugs fall out of their receptacles when contacts are worn What it means: Worn contacts in receptacle no longer grip the prongs firmly. Code violation? No. Danger level: High. Loose contacts can cause arcing, which can ignite dry wood and dust. Solution:Replace the old receptacles as soon as possible. (A new one costs about $2.) Many homeowners feel comfortable doing this themselves. Electricians will charge about $8 or $10 per outlet, although there's likely to be a minimum charge for small jobs.

Electrical Upgrades Many homeowners who think nothing of tackling painting, carpentry and plumbing projects turn timid. When it comes to electrical work, a little fear isn't necessarily bad when dealing with electricity — it could keep you from making a serious mistake. But that doesn't mean there aren't electrical projects you can handle. All you need is an understanding of how the electrical code applies to your project and some instruction on making proper wire connections. To safely guide you through theseupgrades, we've included photographs that outline the basic steps and illustrations that show all the wiring connections. Consult with an electrician if your home is wired differently than the ways illustrated. If you're still not feeling confident, here's an alternate approach: Run cables, install boxes, and wire in switches and outlets, then hire an electrician to make the final power hookups and check for any code violations. (Most municipalities allow you to do your own electrical work, though you're never allowed to wire someone else's home.) Also, get the proper permits from your local building department before starting. It's the law, and you'll also get the benefit of having your work checked both at the rough-in stage and when it's completed.

Before starting work, turn off the power at the main service panel. Plug a lamp or circuit tester into the circuit you're working on to confirm the power is off. Finally, if you have any questions or concerns, always consult with a licensed electrician or building inspector before you proceed. Electrical work isn't difficult, but the consequences for not doing it right can be serious.

Installing a Floodlight One of the simplest, most effective ways to enhance the safety and security of your home is to add a motion-sensor floodlight to the garage. The dual-lamp model installed here comes on automatically if something—or someone—crosses its field of vision. If you’re hesitant about working with electricity, don’t worry. We’ve greatly simplified the process by safely tapping into an existing garage circuit and by running the wires through surface-mounted metal tubing, called conduit. This technique speeds the installation by eliminating the need to blindly pull wires through walls and ceilings. All of the supplies required for this project are sold at hardware stores and home centers, including the thin-wall metal conduit, which is referred to as EMT for electrical metallic tubing.

Tools for This Project: Side-cutting lineman's pliers Wire stripper Magnetic torpedo level 12-inch-long 7/8-inch spade bit Tape measure Phillips-head screwdriver Drill/driver Ladder Fish tape Hacksaw (to cut conduit) Round file or reamer (to remove burrs on just-cut conduit) Utility knife

Supplies You Will Need Floodlight: 1. Round outlet box 2. Lamp-holder cover 3. Motion sensor 4. Lamp holders (2) 5. 90-Watt halogen bulbs (2) Wiring: 6. 14-Gauge insulated stranded wires 7. Twist-on wire connectors 8. Electrical tape 9. 14/2 Nonmetallic cable (aka romex) Hardware: 10. 1/2-Inch emt conduit 11. Conduit elbows 12. Conduit hangers 13. Straight conduit couplers 14. Right-angle connectors with removable covers 15. Cable connector 16. Metal junction box 17. Extension box with connectors 18. Combination 15-amp GFCI receptacle and switch 19. 2-Inch galvanized decking screws (for attaching electrical box to wall) 20. Silicone caulk (to seal hole)

Overview The floodlight shown here has two lamps and an infrared motion sensor, which automatically turns on the lights if a person or vehicle approaches the garage (they go off after a few minutes). Home electrical projects like this typically require you to connect wires to the main electrical panel and then fish them behind walls, under floors, and above ceilings—not an easy job. However, the wiring for this driveway floodlight is confined to the garage, so you can tap in to an existing electrical outlet and then use easy-to-install surface-mounted metal conduit to run the wiring. The 1⁄2-inch-diameter conduit, known as EMT (electrical metallic tubing), is sold at home centers and electrical suppliers for about 20 cents a foot. You can also purchase right-angle conduit connectors ($4) and preformed curved elbows ($3) that allow you to turn corners with the rigid metal. Master electrician Allen Gallant suggests replacing the two-plug outlet with a combination GFCI receptacle and switch ($22) brought out from the wall with an extension box ($4.50). He prefers to assemble a fixture from separate parts (about $60 total) instead of buying a single unit because that way he’s able to upgrade the quality of the motion sensor. WARNING: Before starting this project, turn off the electricity to the garage at the main electrical panel. Then test the garage receptacle by plugging in a radio or lamp to confirm that the power is off.

Step by Step

1. Attach the extension box • After turning off the electricity to the garage, remove one of the existing wall receptacles. • Screw the metal mounting plate that comes with the extension box to the electrical box in the wall. • Use a screwdriver to pry the round knock-out plug from the top of the extension box. Attach a 1/2-inch metal conduit connector to the top of the box. • Fasten the extension box to the mounting plate with the two long screws provided.

2. Connect the conduit • Measure from the top of the extension box to the garage ceiling and then subtract 1 1/2 inches. Saw a piece of conduit to that dimension and file smooth any sharp burrs. • Slide a right-angle connector onto one end of the conduit. Insert the other end into the connector on the extension box. • Put a conduit hanger on the conduit. Check that the conduit is perfectly plumb, then mark the hanger's position. • Move the conduit and screw the hanger to the wall. Slip the conduit back into place and secure it by tightening the screw on the hanger. TIP: Use a magnetic torpedo level, which sticks to the conduit.

3. Install a preformed conduit elbow • Hold a conduit elbow against the wall corner and cut a piece of conduit to fit between the elbow and the right-angle connector. • Insert the conduit into the right-angle connector; if it's longer than 12 inches, install a conduit hanger. • Join elbow to the conduit with a straight coupling. • Continue installing conduit across the front wall, ending it over the center of the garage door. Use hangers every 12 inches.

4. Bore through the garage wall • Measure from the top of the doorway to the ceiling and subtract 1 inch. Then move outside and mark the siding that dimension up from the center of the door. • Bore a level hole through the garage wall with a 7/8inch-diameter spade bit (see photo above). • Inside, connect a junction box to the conduit running across the front wall. Then screw the box to the ceiling. • Run a length of 14/2 nonmetallic cable (Romex) from the junction box through the hole to the outdoors.

5. Attach the round outlet box • Fasten a cable connector to the hole in the base of the round outlet box. • Feed the nonmetallic cable through the connector, then tighten the connector screw. • Fill the hole in the wall with silicone caulk or putty. • Press the round outlet box flat against the siding and secure it with two 2-inch-long galvanized decking screws. TIP: Use a connector wherever a cable or wire enters a box.

6. Pull the wires through the conduit • Remove the cover plate from the right-angle conduit connector that's nearest the wall receptacle extension box. • Feed an electrician's fish tape into this connector and push it through the conduit until it comes out the extension box. • Use electrician's tape to attach one each of black, white, and green 14-gauge stranded copper wires to the fish tape. • Pull the fish tape until the wires come out of the connector, then undo the fish tape. • At the junction box, push the tape into the conduit. Reconnect the three wires to it, then pull them into the box.

7. Assemble the floodlight • Carefully screw the motion sensor into the center hole in the round lamp-holder cover. • Thread the two lamp holders into the holes on either side of the motion sensor. • Finger-tighten the motion sensor and lamp holders; don't use pliers. Final tightening and adjustment aren't done until after the floodlight is mounted on the garage wall. TIP: If desired, spray-paint the floodlight to match the house. But not the sensor — paint might impede its performance.

8. Make the connections • Trim the cable coming from the round outlet box to 6 inches and use a utility knife to cut away the plastic sheathing. • Use wire strippers to remove 1/2 inch of the plastic insulation from the black and white wires. • Join the cable to the floodlight, as detailed in "Wiring Connections". • Attach the floodlight with machine screws and insert bulbs. • Make the wire connections at the junction box and switch. Then turn on the power and adjust the lamp holders and motion sensor.

Adding Outlets To a Garage

If you're tired of stringing an extension cord across the garage every time you want to vacuum out the car or belt-sand a board, install a new wall outlet, or duplex receptacle. In our garage, we tapped into a ceiling outlet to provide power to the new wall outlet. We ran ½-inchdiameter, thin-wall metal tubing, or conduit, across the ceiling and down the wall. (Conduit is sold in various lengths for about 20 cents per linear foot; it's also referred to as EMT, for electrical metallic tubing.) To bend conduit, electricians use a simple hand tool called a conduit bender. We took the easy way out and bought preformed 90-degree conduit elbows ($2 each). Once the conduit is installed in your garage, push three 12-gauge, single-strand copper wires (25 cents per foot) through the tubing. There should be one white wire, one black wire, and one green grounding wire. At the end of the conduit, install a 4-inch-square metal box ($2.30) and two duplex outlets. As the illustration shows, one of the outlets is a GFCI, or ground-fault circuit interrupter outlet ($10), the other a standard grounded outlet ($2); they're wired so ground-fault protection is provided for both. Note that one white wire goes from the top, left-side terminal screw on the standard outlet to the top, left-side "load" terminal on the GFCI. The black wire takes a similar route from the top, right-side terminal screw on the standard outlet to the top, right-side "load" terminal on the GFCI. The long, continuous ground wire runs from the metal box to the GFCI and then to the outlet. According to the National Electrical Code, all garage-wall outlets must be GFCI outlets or standard outlets protected by GFCI circuit breakers. Code Reminders •

Conduit connectors must be used to secure thin-wall conduit to metal boxes.

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Garage-wall receptacle outlets must be protected by a GFCI at the outlet or by ground-fault circuit interrupters in the main service panel. All metal boxes must be properly grounded.

1. Turn off power to the section of the house where you will be working. Then test ALL outlets and switches with a tester to make sure the power is off. After removing the outlet from the garage ceiling, screw an extension ring to the existing box. Also, remove the knockout plug in the end of the ring for attaching the conduit.

2. Use metal pipe hangers and toggle bolts to hold the conduit to the drywall ceiling. Push the springloaded toggle up through a hole; tighten the screw to secure the hanger.

3. Push the conduit up into the hangers, then slide it into the extension ring. Thread a machine screw into each hanger and tighten it to hold the conduit firmly in place.

4. Use a preformed conduit elbow to turn the corner where the conduit runs parallel with the wall. Join the elbow to the two straight conduit pieces with slip-on connectors.

5. To mount the metal receptacle box to the concrete-block wall, drill three holes in the wall and insert plastic anchors. Slide the box onto the conduit and screw it to the wall.

6. After the conduit is installed, push single-strand copper wires into the extension ring and through the conduit until they appear at the receptacle box mounted to the wall.

7. Fasten the two outlets to the cover plate, then screw the plate to the box. The standard outlet on the left is wired to the GFCI outlet on the right; both are ground-fault protected.

Replacing an Outlet with a GFCI Circuit

Ground-fault circuit interrupter outlets prevent accidental electrocution, and code requires them in baths, kitchens, laundry rooms, garages and outdoor locations. A GFCI has a built-in circuit breaker that interrupts the flow of electricity the instant it senses a ground fault or current leak. But a GFCI won't work unless it's properly connected. If your electrical system has not been upgraded for 20 years or more, you probably need to install GFCIs.

Code Reminders • All countertop receptacle outlets must be protected by a GFCI device installed at the outlet or by GFCI circuit breakers. • A kitchen must have two 20-amp circuits for countertop appliances. • There should be countertop receptacles installed so that no point along the counter is more than 2 ft. from an outlet.

Here's how: 1. Turn off the power to the outlet you will be replacing. Test to see the power is off.

2. Remove the old outlet. After turning off the electricity to the kitchen at the main service panel, remove the cover plate and unscrew the outlet from the box. Disconnect the wires and remove the old outlet.

3. Wire the new outlet. At the back of the GFCI are screw terminals marked "load" and "line." The single screw at the bottom is the grounding screw. Attach both the black and white wires to the screw terminals on the line side. Fasten the black wire to the dark-colored screw and the white wire to the lightcolored screw. Again, make sure that both wires are on the "line" side. Wrap the bare copper wire around the grounding screw and tighten it.

3. Install the outlet in the wall. Neatly tuck the wires into the box, screw the outlet in place and replace the cover plate. 4. Check the GFCI. Press the "test" (power off) and "reset" (power on) buttons--the outlet should go dead. Reset to resume current flow.Replacing Two-Prong Receptacles

Replacing Ungrounded Outlets

Two-prong receptacle (undergrounded)

Three-prong receptacle (undergrounded)

GFCI receptacle (undergrounded) Old-fashioned two-prong receptacles connected to two-wire cables don't have the ground wires that protect people and electrical devices in case of a fault. Yet it is possible to retrofit a new three-prong or GFCI receptacle into the same outlet box without any rewiring, as long as the box itself is grounded. Luckily, metal boxes attached to armored, or BX, cable—a type of wiring commonly found in old houses—generally are grounded; the cable's flexible metal jacket serves the same purpose as a dedicated ground wire.

Tip Even if an outlet box isn't grounded, installing a GFCI in it will still protect you (and your tools and appliances) from ground faults. But an ungrounded GFCI can't safeguard sensitive electronics, such as a computer or phone, from the interference caused by stray currents. The National Electrical Code requires you to stick a label on the receptacle that reads, "No equipment ground." These labels come in the box with a new GFCI.

To switch out your receptacles, just follow these steps: 1. Turn off the power to the outlet and test that power is off with tester. 2. Check for ground. Insert one prong of a circuit tester into the receptacle's hot slot (the shorter one), and touch the other to a screw that secures the cover plate. The tester should light up. If it does not, the box is not grounded. You can install a GFCI (see tip at bottom), or call an electrician to fix the wiring. 3. Remove the old receptacle. Turn off the power at the breaker panel or fuse box. Unscrew the old receptacle from the box and detach the wires. 4. Connect the new receptacle. Attach the black (hot) wire to the brass terminal and the white (neutral) wire to the silver. On a GFCI, use the terminals in line with the "line" label on the back of the receptacle. (If your box is not grounded, skip to Step 6.) 5. Fasten the ground screw. This green screw, sold in hardware stores, fits in a threaded hole in the back of the box. Hook one end of an 8-inch green grounding wire or pigtail (also available at hardware stores) to the screw and tighten it. 6. Ground the receptacle. Secure the other end of the 8-inch grounding pigtail to the green grounding terminal on the three-prong or GFCI receptacle. Insert the new receptacle into the box. 7. Turn on the power. Use a circuit tester to make sure the circuit is working.