Replacing a wall switch in 4 steps

Changing an electrical wall switch is one of the simpler electrical do-it-yourself jobs you can undertake, but it doesn't mean that you should be any less careful. Follow these steps for safely replacing a wall switch.

•  Turn off power to the switch, remove the cover plate, and loosen the switch's mounting screws.
• Gently pull the switch out of the box and use a voltage tester to make sure the circuit is dead.

• Loosen the switch's screw terminals and disconnect the wires — depending on the circuit, they both may be black, or one may be black and the other white with black tape around it (a white wire, usually neutral, is recoded black to indicate that it's functioning as a hot wire).

• Connect the new switch by hooking the hot wires' bare leads clockwise around its terminal screws.
• Tighten the screws.
• The new switch will have a green grounding screw, which the old one may not have had.
• In that case, run a pigtail from the green screw to the grounding wires in the box.

• Push the wires and switch back into the box.
• Screw the switch to the box.
• Reinstall the cover plate.
• Restore power.

Making correct and secure wire connections is essential to trouble-free electrical installations or repairs — but not everyone knows how to pigtail, hook, or splice. Below is a quick rundown these skills.

• Joining wires usually requires removing about two centimetres (3/4 inch) of insulation from their ends with a wire stripper or a multipurpose tool.
• To strip wire with a multipurpose tool, insert the wire in the correct size notch, then close and rotate the tool until the insulation is cut through and you can slide it off.

• Use a screw-on wire connector (wire nut) to join wire to wire.
• Hold the stripped ends of solid wires together and twist the wire nut on clockwise.
• Twist the bare ends of stranded wires together, then screw on the connector.

• To connect wire to a screw terminal, use needle-nose pliers to bend the stripped end of the wire into a loop.
• Wrap the loop clockwise around the screw, and tighten the screw.

• Pigtails are used so that a failure in an outlet won't interrupt the whole circuit.
• When joining two wires to a switch or receptacle terminal, use a wire connector to join the two wires to a short length of wire called a pigtail; connect the pigtail to the screw terminal.
• Never connect more than one wire to a single terminal. (This isn't a hard rule to remember — most terminals are designed to hold only one wire.)