Install a Dimmer Switch
Category: Electrical ·
Difficulty: Beginner ·
Time: 0.7h ·
Estimated cost: $35
Tools needed
- Voltage tester
- Phillips screwdriver
- Wire strippers
- Needle-nose pliers
- Electrical tape
Materials needed
- LED-compatible dimmer switch (1 ea)
- Wire nuts (assorted) (1 pk)
- White cover plate (1 ea)
Execution steps
Kill the circuit
Flip the breaker for that room off. Stick the voltage tester on the existing switch wires — confirm zero before you touch anything.
Duration: 5 min
Remove old switch
Unscrew the cover plate and switch. Pull the switch out of the box and note which wires are hot, load, and ground.
Duration: 10 min
Match the wires
Connect the dimmer's black lead to the line wire, the red/black lead to the load wire, and the green lead to the bare ground using wire nuts. Twist clockwise.
Duration: 15 min
Stuff and screw
Fold the wires neatly into the box. Secure the dimmer to the box with the included long screws.
Duration: 5 min
Mount cover and test
Snap on the cover plate. Turn the breaker back on and test the slider through its full range with the lights on.
Duration: 5 min
Safety first
- ALWAYS confirm the wires are dead with a tester before grabbing them — breakers can be mislabeled.
- Use an LED-compatible dimmer; old incandescent dimmers buzz and flicker LEDs.
- Three-way switches need a three-way dimmer. Check the box before buying.
When to hire a pro
Aluminum wiring, no ground wire in the box, or a box with more than two cables — call an electrician.
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