Changing Electrical Switches

Changing a wall switch can be pretty simple, but having some basic knowledge of the different types of switches and how to replace them can be most helpful.

Types of switches
A Single-Pole switch controls a light/receptacle in one location only. The switch has two screws of the same color.

A Three-Way switch operates in pairs to control a light/receptacle in two locations. The switch has two screws of the same color (either brass or silver), and one screw of another color (either copper or black). This copper or black screw is called the common terminal screw.

A Dimmer switch is wired as the single-pole switch and have either terminal screws or lead wires.

CAUTION: Before working on any switch, make sure the power to that switch is SHUT OFF.

Replacement Tips
Read ALL information embossed on the back of the new switch, which should have the same amp and voltage ratings as the old.

Pay attention to marks on the replacement switches, and make sure they match up to your existing switch. If your home’s wiring is aluminum, use only replacement switches marked CO/ALR. Replace unmarked switches and switches marked CU/AL with switches marked CO/ALR. Don’t backwire switches to aluminum wiring, attach aluminum wires to terminal screws only.

Replacing a Single-Pole Switch
Remove the cover plate.
Remove screws and pull out switch carefully.
Unfasten the wires.
Loop the stripped wired ends clockwise around the terminal screws on the new switch.
Tighten the terminal screws with a screwdriver (hand tight).
Replace the switch back into the box so you don’t crimp the wires.
Replace the screws securing the switch to the box.
Replace the cover plate.

Replacing a Backwired Single-Pole Switch
Remove the cover plate.
Remove screws and pull out switch carefully.
Using a small bladed screwdriver, press the screwdriver into the release slots on the back of the switch, then pull wire out of slots.
Push in the stripped wire ends into the slots on the new switch.
Replace the switch back into the box so you don’t crimp the wires.
Replace the screws securing the switch to the box.
Replace the cover plate.

Replacing a Three-Way Switch
Remove the cover plate.
Remove screws and pull out switch carefully.
Make sure you label the wire to the common terminal screw with tape.
Install the new switch, attaching the labeled wire to the common terminal screw (black or copper.)
Re-connect each remaining wire to either of the remaining screws.
Replace the switch back into the box so you don’t crimp the wires.
Replace the screws securing the switch to the box.
Replace the cover plate.

Installing Dimmer Switch with Terminal Screws
Remove the cover plate.
Remove screws and pull out switch carefully.
Loop the circuit wires clockwise around the terminal screws on the dimmer.
Replace the switch back into the box so you don’t crimp the wires.
Replace the screws securing the switch to the box.
Replace the cover plate.

Installing Dimmer Switch with Lead Wires
Remove the cover plate.
Remove screws and pull out switch carefully.
Connect the circuit wires to the dimmer’s lead wires, twisting them together.
Screw on wire nuts and insert the dimmer in the box.
Replace the switch back into the box so you don’t crimp the wires.
Replace the screws securing the switch to the box.
Replace the cover plate.

Tips on how to strip electrical wires
Use a utility knife or penknife to strip insulation off the ends of the wire.
Use the knife blade to cut through the insulation all the way around, then pull the insulation off the wire.
Be careful not to nick the wire when you cut as a nicked wire breaks more easily.
If you do nick the wire, just start over and cut the wire back to the nick.

For the best results, purchase a wire stripper at your local hardware store.

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