Home Improvement: How to Replace a Standard Switch with a Dimmer Switch

Reasons abound to replace a common light switch with a dimmer switch. The longstanding reason that it can help set the ambiance of the room is still around. Suggestions have been made that it is easier on the eyes if you dim the lights and dim your computer screen. There is also a belief that this same concept works for television watching. Making the conversion to a dimmer switch is relatively easy and safe if you follow a few guidelines.

Evaluate the load that will be on the dimmer that you plan to install.

Unlike most traditional light switches, dimmers are designed to carry specific loads. If you are replacing a switch for a single fixture that does not have more than 300 watts of lighting, most standard dimmers should do just fine. Above that level, a light duty residential dimmer could become a fire hazard. For loads reaching 1500 watts or more, you probably should consider a heavy duty commercial dimmer. These are quite expensive, but will safely handle this larger load.

Turn off the power to the switch that you are going to swap for a dimmer.

Go to the breaker box and turn off the breaker that controls the circuit where the new dimmer will be installed. A simple way to test this is to turn on the light. If the light goes off as you turn off the breaker, it is the one you need off. You can flip the breaker a time or two to test it if you want to be more cautious.

Use a screwdriver to remove the face plate from the existing switch.

You will see two screws going through the switch into the switch box behind it. One screw will be at the top and one at the bottom. Remove these screws to free the switch from the box. Grip the switch and pull it gently out of the box until the wires behind it are extended and exposed.

Take a look at how the wires are attached to the current switch.

If the wires are wrapped around two screws on the sides of the switch, loosen the screws and remove the wires. If the wires are inserted into two holes in the back or on the sides of the switch, you may be able to loosen the screws and pull the wires out. If you have any problems with this, just use a pair of side cutters and snip the wires as close to the switch as possible.

The switch may have the bare neutral wire attached to a green screw.

If it does, loosen the screw and remove it. Set the switch aside for later use or disposal. You are ready to install the dimmer.

Look at the dimmer to see how to best install the wiring.

If the dimmer has instructions with it, read them to make sure it does not require some type of special wiring to work. This is not normally the case.

Make sure the ends of the wires are in good condition.

If you had to snip the wires, you will want to strip the insulation back about an inch from the end of the wires. If the wires look damaged, you may need to trim them back a little more to make sure that you can make a secure safe connections. Be careful not to trim the wires too much, or they may be too short to connect to the new dimmer switch.

The connections on the dimmer should resemble those on the old switch.

Just like the switch you removed, you will attach the wiring either into holes near the screws on the dimmer or wrap them around the screws. Once the wires are in place, tighten the screws as much as possible to secure the wires. If there is a screw for the neutral, attach it to the switch. If not, fold it back out of the way.

Ease the wiring and the new dimmer back into the switch box.

Use the screws that came with the dimmer and attach the dimmer to the switch box at the top and bottom. If you did not get new screws, you can use the old ones from the previous switch. The dimmer may require a different style of switch cover. You may want to ask about this at your home store before purchasing the dimmer.

Attach the correct type of cover to the new switch.

If you have a dimmer with the turn type of mechanism, you will need to push the dial or knob onto the stem of the dimmer to complete the installation. Turn on the breaker to finish the job.