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Home: Electricity and Electrical: How to Install a Dimmer Switch

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How to Install a Dimmer Switch

Written by; Thomas O'Connor / TCCN Staff Writer
Added on: Sun Sep 27 2009


Dimmer switches are great for customizing your light. At night you can turn it all the way up, and when there's some daylight getting in you can turn it up only as much as you need to.

A typical single pole switch can usually be replaced with a dimmer switch. You need to make sure that there is enough room in the electrical box, and that it is an incandescent light. Don't use a dimmer switch with a fluorescent light. And don't use the same switch to control both a fluorescent and an incandescent light.

Dimmer switches for fluorescent bulbs have to be exactly matched with the fixture. If you try to put a dimmer on a switch for a fluorescent light, it will probably only work when it's all the way "on," and it might not work at all. Leave the dimmer switches to the incandescent lights.

When you buy your dimmer switch make sure you also have the correct size wire connectors. Dimmer switches have wire leads rather than screw terminals.

In addition to your dimmer switch and wire connectors, you'll need the following:

1) Neon circuit tester
2) Screwdrivers
3) Needle nose pliers
4) Combination pliers

Step 1.

Important: Turn off power to the circuit at the main panel. Use your neon circuit tester to be certain that the power is turned off.

Step 2.

This step only applies if you're replacing a three way switch. If not, skip to Step 3. If you are replacing a three way switch, memorize how the old switch is wired before you remove the wiring. Either draw a diagram or snap a quick photo so you can look at it to remember.

If you have a three way dimmer, it has an additional wire lead. It is connected to the common circuit wire. With a three way switch, the common circuit wire is attached to the copper screw terminal or the darkest one on the old switch. It may have the word "COMMON" on the switch. Only one of the pair of three way switches can be a dimmer switch. Both will turn the fixture off and on, but only one can regulate its intensity.

Step 3.

Using your wire connectors, connect the wire leads from the dimmer switch to the circuit wires. The leads are interchangeable. They can be attached to either of the two circuit wires. If your dimmer switch has a green third wire, it's a grounding lead. You attach this to the grounded metal electrical box or the bare copper grounding wire of the circuit.

Replace the parts in the electrical box, attach the wall plate. Only then should you turn the electricity to the switch back on.

There you have it. now you can save a bit of energy and adjust your room light to your liking.

Remember if this task is too big for you to take on, please try calling in a certified electrician for the job. You can find many right here at, by searching through our local directory.

Happy home improvements!


Copyright: 2009

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