A dimmer switch will help change the light level in a room, making it bright enough for reading or low enough for romance. But there is one caution – dimmer switches don’t work on most fluorescent fixtures, just regular incandescent lights.
Most dimmer switches can handle 600 to 1000 watts of power so before you buy a dimmer switch (here’s a bunch of different types from the Home Depot), check the rating that the model you’ve chosen. Count the number of bulbs that the switch controls and add up the wattage of each light bulb. The total wattage should not exceed the rating.
First turn off the power to the switch at the circuit fuse panel. Unscrew and remove the switch plate then use a voltage tester to make sure that the circuit is dead. It should read zero.
Now you’re ready to unscrew the switch from the electrical box and pull it out with the wire still attached.
Next remove the wires from the old switch. Unlike standard switches that are connected by screw terminals, dimmer switches are usually connected by short wires that come out at the switch body. Twist the wires together and then screw on the wire nut.
Use the connectors or wire nut supplied with the fixture to attach the black wires coming out of the dimmer switch to the colored wires in the box. It doesn’t matter how you pair the wires as long as you don’t use the copper ground wire.
Next, attach the green wire to the ground wire in the box. Push the new switch back into the electrical box and screw it into place and screw on the switch plate. Then just push the control knob (if there is one) onto the switch. Your final step is to turn on the power, and you’re good to go.