Stripping and splicing wire
When splicing two wires together, strip off about 1 inch of insulation. If the wire will be joined to a terminal, remove about 3/4 inch.
ALUMINUM WIRE - Connecting copper to aluminum wires causes corrosion and is both dangerous and against code unless you use special connectors.
MATERIALS: Wire, wire nuts, electrician’s tape
TOOLS: Combination stripper, lineman’s pliers or side-cutting pliers
1 STRIP WIRES WITH A COMBINATION STRIPPER. To use a combination stripper, slip the wire into the correct-size hole, squeeze, twist, and pull off the insulation. Yellow-handled strippers are for solid wire. Red-handled strippers are for stranded wire, like that found in lamp cords.
2 TWIST WIRES TOGETHER. Hold the stripped wires side by side. Grab both with lineman's pliers. Twist clockwise, making sure that both wires turn. Twist them together like a candy cane to form a neat-looking spiral; don't over twist or the wires may break. SPLICING THREE OR FOUR WIRES. When twisting three or four wires together, hold them parallel and twist them all at once with lineman's pliers.
3 CUT THE END. Using the lineman's pliers or side-cutting pliers, snip off the end of the twist. Leave enough exposed metal so that the wire nut will just cover it—about 1/2 inch usually does it.
4 CAP WITH A WIRE NUT. Select a wire nut designed for the number and size of wires you have spliced. Slip the nut on as far as it will go, then twist clockwise until tight. Test the connection by tugging on the nut; it should hold securely for dependable protection. Wrap electrician's tape around the bottom of the cap.
Joining wire to a terminal
MATERIALS: Wire, device with terminals
TOOLS: Long-nose pliers, side-cutting pliers, wire-bending screwdriver
Joining wire to a terminal is an important skill and a key step in most electrical projects. Do this step properly to ensure the device works and doesn’t develop a short.
MAKING THE RIGHT CONNECTION. Electricians wrap the wire nearly all the way around the screw to make a connection that is completely reliable; with some practice, you can make joints just as strong. Bend a wire in a quarter circle, slip it under the screw head, and tighten the screw.
Many devices come with terminal screws unscrewed. Screw in any unused terminal screws so they won’t stick out dangerously, creating a shock hazard should the terminal touch a metal box.
When removing an old device, you may find spliced wire wrapped with rubberized tape covered with doth friction tape. Slice the friction tape with a utility knife to remove.
USING PIGTAILS - Codes prohibit attaching two wires to one terminal on a switch or receptacle. If you need to attach two wires to one terminal, use a pigtail splice. Cut a wire 6 inches long, and strip both ends. Splice the two original wires to the pigtail and join the pigtail to the terminal.
1 START A LOOP. Check that the power is shut off. Strip about 3/4 inch of insulation from a wire end. Using long-nose pliers or the tip of a combination stripper, grab the bare wire just above the insulation and bend it back at about a 45-degree angle. Move the pliers up about 1/4 inch beyond the insulation, and bend again in the opposite direction, about 90 degrees.
2 OPTION A: BEND A QUESTION MARK. Use long-nose pliers to form a near loop with an opening just wide enough to slip over the threads of a terminal screw. Move the pliers another 1/4 inch away from the insulation, and bend again to form a shape that looks like a question mark.
2 OPTION B: USE A WIRE-BENDING SCREWDRIVER. This simple tool makes perfect hooks every time. Just push the stripped wire between the screwdriver shaft and the stud at the base of the handle. Twist the handle to make a perfect loop.
3 SQUEEZE THE LOOP AROUND THE SCREW. Make sure the terminal screw is unscrewed enough to become hard to turn. Slip the loop over the screw threads, with the loop running clockwise. Use long-nose pliers or a combination stripper to squeeze the loop around the terminal, then tighten the screw.
4 WRAP WITH TAPE. After all the wires are connected to a switch or receptacle, wrap electrician's tape around the body of the device to cover the screw heads and any exposed wires. The tape not only ensures that the wires stay attached, it keeps the terminals from touching the box and risking a short circuit.
Connecting to a 240-volt receptacle - Be certain that power is shut off—there is a dangerous level of power here. Strip about Vi inch of insulation from the wire end. The wire should be straight, not looped. Loosen the setscrew, poke the wire into the hole, and tighten the screw.
GET THE GOOD ELECTRICIAN’S TAPE - The inexpensive electrician's tape often found in large bins at a home center will do the job, but many electricians prefer to use professional-quality tape. It's thicker and has a better adhesive, which allows for a more secure and longer-lasting wrap.
SKIP THE PUSH-IN OPTION - Many receptacles and switches have holes in the back for easy connection of wires. Once you've stripped the insulation (a strip gauge shows you how much), you poke the wire in. To remove a wire, insert a small screwdriver into a nearby slot. The wire releases. The system works, but the resulting electrical connection is not as secure as a connection made using a terminal screw. Most professionals don't trust this method even though it saves time. Take the extra minute to do it right.
Receptacle and switch wiring
When you remove an electrical cover plate and pull out a switch or receptacle, you may find an arrangement involving a few wires going directly to the device. Or you may find a multicolored tangle of wires, some related to the switch or receptacle and some not. Here are some of the most common wiring configurations you’ll find behind electrical cover plates.
If your switches receive constant use in a particular area, consider paying a little extra for a device labeled “commercial or “spec-rated The contacts are stronger and the devices are sturdier.
A split receptacle - Also known as a half-hot receptacle, this is connected to two hot wires. The brass tab joining the brass terminals has been broken off. With the tab broken, each hot wire energizes one plug. Some split-circuit receptacles have each plug energized by a different circuit so that you can plug in two high-amperage appliances without the danger of tripping a breaker. Others are wired so that half the receptacle is controlled by a wall switch, while the other half is hot all the time.
MIDDLE-OF-THE RUN RECEPTACLE - A receptacle with one cable that carries power into the receptacle and one that carries it to another device is called a middle-of-the-run receptacle. Usually two black wires are connected to the brass terminals and two white wires to the silver terminals. Sometimes the blacks and the whites may be joined, with a pigtail at each splice. Each pigtail is attached to the receptacle. If only one cable enters the box, the receptacle is at the end of the run. The black wire is attached to the brass terminal, the white wire is attached to the silver terminal, and the ground wire is attached to the receptacle.
Installing or replacing a receptacle
MATERIALS: New receptacle, wire nuts, electrician's tape
TOOLS: Screwdriver, lineman's pliers, long-nose pliers, side-cutting pliers, receptacle analyzer, combination stripper, level
If a receptacle doesn’t seem to work, first check that whatever is plugged into it works properly. Replace any receptacle that is cracked. Before buying a replacement receptacle, check the wiring. Usually the wires leading to a receptacle will be #14 and the circuit breaker or fuse will be 15 amps. In that case, install a 15-amp receptacle. Install a 20-amp receptacle only if the wires are #12 and the circuit breaker or fuse is 20 amps or greater.
LOTS OF CONTINUITY - A simple continuity tester works fine on small jobs. If you’re doing a lot of work, you may find one of the noncontact voltage detectors or even a professional-grade tool to be more handy.
1 CHECK THAT THE POWER IS OFF. Turn off power to the circuit. Test to confirm. If the tester shows current, check your service panel and turn off another likely circuit. Test again and proceed only if power is off. Remove the cover plate and unscrew the mounting screws. Being careful not to touch wires or terminals, pull out the receptacle.
2 DOUBLE CHECK WIRES FOR POWER. In a damaged receptacle, wires may be hot even though testing shows no power. Touch tester probes to the top pair of terminals, then to the bottom pair. If you have old wiring and both wires are black, use a receptacle analyzer to check that the neutral wire is connected to the silver terminal and the hot wire to the brass.
3 SNIP AND RESTRIP DAMAGED WIRE ENDS. Once you're sure the power is off, unscrew the terminals and pull away the wires, taking care not to twist them too much. If a wire end appears nicked or damaged or if it looks like it's been twisted several times, snip off the end and restrip it.
4 INSTALL THE RECEPTACLE. Wire the new receptacle as the old one was (each white wire connected to a silver terminal and each black or colored wire connected to a brass terminal). Wrap with electrician's tape to cover all terminals and bare wires. Gently push the outlet into the box. Tighten the mounting screws and check that the receptacle is straight. Replace the cover plate, restore power, and test with a receptacle analyzer.