How to Install a Dimmer Switch

A dimmer switch can make any light fixture in the home versatile by creating a different ambience in the room. Learn how to install one from Mr. Electric.

Are there certain lights inside or outside of your home that, when turned on, cause you to cower and cover your eyes? A dimmer switch can make even blinding lights like these more versatile.

With properly installed dimmer switches, you can create a more comfortable home environment for you and your family. Fine-tune the ambience to your liking — and put yourself back in control of your lights.

If better controlled lighting is what you need, we’ll explain how to install a dimmer switch and walk you through some of the things to consider before purchasing one in the following sections:

  • Lights Too Bright? Installing a Dimmer Switch is Easy
  • How to Install a Dimmer Switch

Lights Too Bright? Installing a Dimmer Switch is Easy

Installing a dimmer switch is easy, but it requires a little bit of forethought.

Before ejecting your current light switches, do your homework. Not all bulbs can be dimmed, including many CFLs and LEDs — so be sure to check the specifications on bulb boxes before purchasing your lightbulbs.

In addition, ceiling fans require special dimmer switches to prevent current fluctuations from damaging the motor. Shop carefully!

How to Install a Dimmer Switch

Time required: About 30 minutes to 2 hours

Materials needed: Wire strippers, screwdriver, voltage detector, dimmer switch (single or three-way), flashlight, and gloves

Installation Steps:

  1. Cut the Power: Cut power at the breaker box (not the light switch). Then use a voltage detector to ensure power has been cut before touching any wires.
  2. Remove the Old Switch: Unscrew and remove the switch plate cover and then the switch. Loosen the wires (typically wrapped around connector screws) — or simply snip off the ends with wire strippers and remove the old switch, using wire strippers to remove ¾-inch of casing from the end for reconnection.
  3. Check Dimmer Switch Instructions: Always make sure you understand which part of the switch is top/bottom, and where the wires go before you attach the parts to one another.
    • Green: Ground or copper wire.
    • Black: Wires going to the dimmer (placed on either gold screw).
  1. Know Your Installation Type:
    • Installation Steps for Standard/Single Pole Dimmer Switches
      (Light is Turned On/Off from Single Location)
      • Connect the green ground wire to a green or exposed copper wire in the wall box, then twist ends together with a wire connector nut.
      • Connect each dimmer wire (black) to the house wires separately. These could be black, white with black markings, or red. Tighten the ends together with wire nut(s).
    • Installation for Three-Way Dimmers
      (Light Can Be Turned On/Off from Multiple Locations)
      • Remove ¾-inch casing from house wires with a wire stripper. If wires are bent, remove the twisted ends first.
      • Connect the green ground wire to a green or exposed copper wire in the wall box and twist the ends together with a wire connector nut.
      • Connect the dimmer wire (black) to your tagged common wire. Remove electrical tape as necessary.
      • Connect the two remaining traveler wires, then separately connect each to the remaining wires in the wall box.
  1. Put Things Back Together: After the wires are attached, install the switch back into the electrical box, followed by the switch cover plate.
  2. Change Bulb(s): Remember, not all bulbs are compatible with dimmer switches, so you’ll likely have to swap out your old bulb before putting your new dimmer switch to use.
  3. Restore Power: Then have fun playing with your new dimmable light!

Smart Installation Safety Practices

  • Ensure safety by tripping the circuit breaker to the switch being replaced. If you only turn the switch off, you run the risk of getting zapped.
  • Always loop the wire around the screw, when possible, to avoid the wiring pulling loose over time. Loop the end into a U shape, pinch the ends together, and tighten the screw.
  • Do not leave bare wires exposed. Trim ends and recap if necessary.

Halfway there? No matter where you stall out in your DIY project, Mr. Electric can help. Complete your project with ease with the help of a Mr. Electric pro today.

This blog is made available by Mr. Electric for educational purposes only to give the reader general information and a general understanding on the specific subject above. The blog should not be used as a substitute for a licensed electrical professional in your state or region. Check with city and state laws before performing any household project.

Related Article: Why is My Dimmer Warm to the Touch?