Wiring a single-pole switch

Installing a single-pole switch is just one in a series of tasks that make up an electrician’s work, but along with running rough wiring and installing boxes, it’s a task that anyone can do and save some money in the process. When wiring a switch, there are two scenarios: You’re connecting two feeds (one power, one to the fixture) or one feed (from the fixture to the switch). The tools you need are basic: Phillips-head and slotted-head screwdrivers, a pair of wire strippers, electrician’s tape, yellow wire nuts (for two conductors), red wire nuts (for three conductors), lineman’s pliers, and a utility knife. If you’d like more information on residential wiring, please consult Rex Cauldwell’s book Wiring a House (The Taunton Press, 2007).

Step 1: Leave yourself enough slack. Pull 8 in. to 10 in. of non-metallic sheathed cable through the box, then trim it back to a 6-in. length, measured from the outside face of the box. The cutters on lineman’s pliers cut cleanly and easily through the cable.

Step 2: There are two ways to skin a piece of non-metallic sheathed cable, but here’s the most foolproof. Make a shallow cut about 2 in. long at the end of the cable. Now grab both black and white conductors, and pull them apart in opposite directions so that the jacket rips, continuing until the tear reaches the inside of the box. Now cut the jacket away, leaving about 1/2 in. inside the box.

Step 3: Stripping the jacket with a knife is trickier. Starting where the non-metallic sheathed cable comes into the box, carefully insert the tip of a sharp utility-knife blade into the jacket’s center, and slice the jacket all the way to the end of the cable. Trim the jacket away close to where the cable enters the box and carefully inspect both black and white insulations for cuts. Any nicks should be covered completely with two wrappings of electrical tape.

Step 4: Strip and bend the hooks. Strip each wire’s insulation back about 3/4 in. Make an open-ended loop on the black wires with needle-nose pliers or wire strippers. Next, make a loop in a 6-in. length of bare ground wire, fasten it around the green screw terminal, and tighten the screw snugly.

Step 5: Connect the pairs. With a yellow wire nut, join the white wires, then use a red wire nut to join the two grounds and a short length of ground that’s connected to the switch. Gently push these sets into the back of the box.

Step 6: Attach the black wire loops to the switch terminals. Always remember to wrap the wire clockwise around the screw so that when the screw tightens, it carries the loop with it.

Step 7: Fold the wires behind the switch, not on the sides. After wrapping the switch body with a layer of tape, fold the black wires back into the box neatly, then push in the switch on top of the wires. Finish by securing the switch’s screws to the box.