A knob- or toggle-controlled dimmer switch allows you to vary the brightness of a light fixture and control the mood of a room.
Most wall dimmer switches are for use with ceiling fixtures that take ordinary incandescent light bulbs and are not suitable for fluorescent light fixtures.
Both toggle- and knob-controlled dimmer switches are designed to fit a standard wall outlet box and replace an existing on-off switch. Toggle switches can usually handle up to 300 watts, while most knob-type controls can accommodate up to 600 watts. Check the package for the wattage capacity of the dimmer switch recommended by the manufacturer. Make sure your fixture wattage does not exceed the dimmer's capacity.
Before working on a switch, turn off the power to its circuit in your home's main service panel, usually found in the basement, garage or utility room.
Dimmer installation is simple and requires no rewiring or renovations:
* Unscrew the cover plate screws. If paint holds the plate to the wall, carefully slit the paint at the plate edges with a utility knife. Set aside the screws and plate.
* Unscrew the two screws, at the top and bottom, which hold the existing switch to the outlet box.
* Pull the switch out of the box.
* Disconnect the circuit wires held by the switch's two terminal screws. Straighten the wire ends.
Before fastening wires together, keep in mind that wire connections must be tight. The easiest way to connect wires is by using cap-like wire connectors, which often come with the dimmer switch.
You'll usually be splicing stranded dimmer wires to solid house wires. Make sure one inch of the stranded wire and one-half inch of the solid is exposed. If necessary, strip off the insulation. Hold the ends parallel. Wrap the stranded wire clockwise around the solid wire. Then screw on a connector clockwise until tight, making sure that no bare wire is exposed.
* Connect the wires from the dimmer switch to the two wires that previously were connected to the old switch's terminals. As in all switch loops, the switch should connect the hot (black or red) wires only. A white wire whose end has been blackened with paint or tape is hot.
* After the wires are connected, fit the wires and the switch into the box.
* Screw the new switch, top and bottom, to the outlet box.
* Mount the cover plate.
* Both types of switches will fit the opening in the cover plate. The shaft of the knob-controlled switch protrudes through the opening. Push the control knob onto the shaft.
* Turn on the power at the service panel.