Dimmer Switch Installation: Single Pole Wiring Step by Step

Choosing the right dimmer

A dimmer switch lets you set the level of light for the function of the room. Dimmers come in two basic wiring configurations. A standard single pole dimmer is used if only one switch controls the light. If two switches control a light or group of lights, a three-way dimmer is needed.

The dimmer must also be rated for the type of lights and number of bulbs. Add up the wattage of all lights connected to the switch to be sure the dimmer can withstand it.

Making the circuit safe

The installation starts by turning off the power at the breaker box. Check by turning the light switch on and off. Then use a screwdriver to remove the wall plate and a voltage tester to make sure there are no active wires.

Removing the old switch

Unscrew the mounting switch from the wall box, gently pull it away from the wall and disconnect all wires from the old switch. If the wires are bent, flatten them or cut off the ends with a wire stripper. Each wire needs three quarters of an inch of bare wire at the end, and the stripper removes casing if needed.

Wiring the single pole dimmer

Connect the ground wire from the dimmer to the green or bare copper wire in the wall box by twisting the ends together clockwise, then cap them with a wire connector. If any bare wire is exposed, unscrew the connector, trim the ends with the wire cutter and recap. Repeat to connect each dimmer wire to the remaining house wires.

Finishing

Tuck the wires back into the electrical box and screw the dimmer into place. Turn the power on and test that the dimmer works properly, then attach the wall plate.