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How to Install a Dimmer Switch

How many handymen does it take to install a dimmer switch? None -- you can do it yourself in a snap.


  • : Working with electricity is very dangerous. Be extremely careful and, if you have any doubts, contact a professional.
  • Step 1: Cut the power Cut the power to the light switch by flipping the circuit breaker or removing the fuse at the main panel.
  • TIP: Make sure the power is off by flipping the light switch.
  • Step 2: Remove the plate Unscrew and remove the light switch cover plate.
  • Step 3: Remove the switch Unscrew the screws that anchor the switch in the electrical box, and remove the switch. It will now be attached by only three wires.
  • TIP: Use a circuit tester to make sure none of the wires going into the switch are live.
  • Step 4: Remove two wires Two of the wires going into the switch will be similar (either both black or one white and one black), while the third will be either a green or bare copper ground wire. Loosen the screws that hold the two similar wires to the switch, then remove those wires.
  • Step 5: Remove the ground wire Now remove the ground wire.
  • Step 6: Cut the ends Cut the ends of the three wires coming from the wall. You’ll use the wire leads that come already attached to your dimmer switch.
  • Step 7: Strip the wires Strip an inch of insulation off the wires coming from the wall. If your ground wire is bare, you won’t need to strip it.
  • Step 8: Attach the ground wires Use a twist-on wire connector to attach the green ground wire from the dimmer switch to the ground wire coming from the wall. Hold the wires next to each other, and screw on the connector in a clockwise direction.
  • TIP: Make sure the bare ends of any insulated wires are completely covered by the connector.
  • Step 9: Attach one wire Using another connector, attach one of the other two wires from the wall to either of the two black wires on the dimmer switch.
  • Step 10: Attach the black wire Using another connector, attach the remaining wire from the wall to the remaining black wire on the switch.
  • Step 11: Screw in the dimmer Screw the dimmer switch into the electrical box.
  • Step 12: Reattach the cover Reattach the light switch cover plate and tighten its screws.
  • Step 13: Attach the knob Attach the knob to your dimmer.
  • Step 14: Restore power Restore power to your switch. Now let that light shine!
  • FACT: Turning an incandescent bulb just a quarter of the way down reduces its energy consumption by 20%.

You Will Need

  • A screwdriver
  • A circuit tester
  • A wire cutter
  • A wire stripper
  • 3 twist-on wire connectors

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