Installing a dimmer switch
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A dimmer switch is one of life's little conveniences that, once installed, you wonder how you ever got along without! Any standard single-pole wall switch is a good candidate for replacement with a dimmer switch – as long as there's ample room in its electrical box and the light bulbs you are using are dimmable.
Don't try to install a dimmer in an undersized box or one that's already jam-packed with circuit wires, and never use a dimmer to control a fluorescent light unless it's one specifically designed for use with dimmers. All types of dimmer switches have wire leads instead of screw terminals, so make sure you have the right size wire connectors on hand.
Shut off power at the service panel. If you're removing an old dimmer switch, pull off the rotary knob with a firm outward pressure. Underneath is a standard switchplate. Remove it. Remove the mounting screws and carefully pull out the switch body.
A dimmer has wire leads instead of terminals. Test for power by slipping the probes of the tester against the base of the wire nuts. If power is detected, shut off the correct circuit in the service panel.
Once you've ensure the circuit is not energized, disconnect the old switch by removing the wire nuts.
Attach the ground wire if there is one. Strip 3/4 inch of insulation from each solid house wire and 1 inch from each stranded dimmer lead. Wrap a lead around a wire with your fingers so that the lead protrudes past the wire about 1/8 inch. Slip on a wire nut and twist until tight. Test the strength of the connection by gently tugging on both wires.
If you replace a three-way dimmer, tag the existing lead wires to connect the new dimmer in the same way as the old one. If only one cable enters the box, attach the black wire to the common terminal and the other two wires to the traveler terminals. If you replace a three-way toggle switch with a dimmer, tag the wire that leads to the common terminal. The other two wires are interchangeable and may be attached using the procedure presented in Step Three above.
