How to Install a Single Pole Dimmer Switch

Sometimes you would like to have a dimmer switch on a light in your dining room, your bedroom, or other space in your home where you would like to reduce severity of light or create ambiance. Installing a dimmer switch is relatively easy as long as you are careful.

Step 1:  Safety First

Turn on the light switch connected to the light fixture you are installing the dimmer. Switch off breakers in your breaker box until the light turns off. This will remove any electricity from the switch, and keep you from being electrocuted. Make sure that you also have adequate light in the room after you have shut off the breaker. Use a lamp or flashlight if necessary.

Step 2:  Remove Toggle Switch

Remove the standard single-pole single-throw toggle switch from the wall outlet. Use a flat head screwdriver to remove the face plate. Release the switch from the hole using a screwdriver. Gently pull the switch from the mounting hole and disconnect the wires from behind the switch. Make sure to verify no voltage before working with the wires by using the voltage tester.

Step 3:  Disconnecting Wires

To disconnect the wires unscrew the connectors from the back of the switch and remove the wires. Remove the two insulated wires and the ground wire also. If the wires are hooked, cut off the bend and strip back the insulation for a clean connection on the new dimmer switch. You do not have to cut off the hook on the ground wire. Discard the old switch.

Step 4:  Inspect Dimmer Switch

Make sure that the package containing the dimmer switch also holds four screws, a faceplate, and the dial cap. There will also be two wire nuts but many times these are not of a very good quality, you might wish to purchase better quality wire nuts to be sure. Attach the ground wire to the green screw on the back of the dimmer switch. Using wire nuts connect the two lead wires on the back of the dimmer switch with the wires coming from the wall opening. Once the wire nuts are secured on the wires wrap electrical tape around the wire nuts as a secondary precaution.

Step 5:  Mount Dimmer Switch to Wall 

Carefully push all the wires into the mounting block in the wall. Be sure to not disconnect the wire nuts or the ground wire. Guide the dimmer switch back into the hole and use the two longer screws to adhere the switch to the mounting bracket in the wall. Mount the face plate to the dimmer switch assembly and use the two remaining screws to attach it securely. Be careful to not tighten too much because it can crack a plastic cover or bend and warp a metal one. Install the dial cover to the switch. It will be keyed in a D-shape. Make sure to align the flat edges to ease the dial on. This will keep the plastic from cracking.

Step 6:  Finish

Once the switch is installed, mounted and finished, turn the breaker back on and test the switch. All incandescent bulbs can be dimmed, but if you use the new fluorescent bulbs be sure you have one designed for dimming.