Hyderabadghar/Do it your self/Wiring a Single-Pole Dimmer Switch

A dimmer switch allows you to regulate the luminosity, or brightness, of the light emanating from a light fixture—either to set a mood or simply to conserve energy. Available in many styles, dimmer switches can be either single-pole or three-way switches. In the case of a three-way configuration, however, only the dimmer switch will regulate brightness, while the alternate switch will merely turn the fixture on or off. Although not commonly used, dimmer switches are available for fluorescent lighting as well as for incandescent.

Dimmer switches are controlled by a solid-state device within the switch that alternately turns the current on and off as many as 120 times per second. By restricting the flow of current, the switch dims the light. The longer the current is off, the dimmer the light. Standard dimmer switches are rated for 600 watts, or six 100-watt light bulbs.

Dimmers are available in a variety of types, from those having something that looks like a conventional toggle but which regulates smoothly, to those having rotating dials or a lever that slides up and down. There are even automatic dimmers that are operated by electronic sensors, and some with faces that light up in the dark to help you find them at night. (Fig. 1)

Fig. 1

PROJECT BASICS

Project: Easy
Estimated Project Time: 30 minutes
Estimated Project Cost: $25.00 for materials; $40.00 - $60.00 for tools
Start Tips: There are many styles and types of dimmer switches; be sure to purchase one with the appropriate rating for your situation.
Safety Tips: If the switch is at the end of a run, be sure to mark the neutral (white) wire with black tape to indicate that it is being used as a hot wire.
Recommendation: Do-it-Yourself

Fig. 2

INSTRUCTIONS

1) Disconnect the circuit wires
Before starting work, turn off the power to the circuit for the existing switch that you'll be replacing.

Remove the cover plate on the switch box, and then pull out the existing switch. Using a circuit tester, check the circuit to be sure that the power is turned off, taking care not to touch the wire terminals while doing so. (Fig. 2)

A single-pole dimmer switch has two wire leads plus a ground lead, and it controls a circuit from one location only.

Fig. 5

3) Connect the dimmer switch for an end-of-the-run:
the switch is at the end of a circuit, you'll have only one two-wire cable plus ground coming into the switch box. Splice one of the lead wires from the new dimmer switch to the black wire in the switch box, and the other lead to the white wire in the switch box. The incoming white wire should be taped black to indicate that it is being used as a hot wire now. Because they are interchangeable, either of the dimmer wires may be spliced to either of the hot wires (black and white-taped-black). Cap the splices with a wire connector.

If there was a bare-copper ground wire connected to the old switch; then connect it to the green wire provided on the dimmer. If you have a metal electrical switch box, be sure there is a pigtail ground wire connecting to the ground screw on the metal box from the ground wire splice.

Place the dimmer switch inside the switch box and replace the cover plate. (Fig. 5).

For a middle-of-the-run:
If the switch is at the middle of a circuit, meaning that the light it controls comes later in the circuit, you'll have at least two cables coming into the switch box. The following are guidelines on how to connect the cables if each contain two wires plus ground.

Splice the black lead wires from the new dimmer switch to the black wires from each of the cables in the switch box. Because they are interchangeable, either of the dimmer wires may be spliced to either of the hot black wires. Cap splices with a wire connector.

The neutral white wires from the two cables will be connected to each other; keep them connected as is. The dimmer switch will not connect to them.

If there were bare-copper ground wires from the two cables connected to the old switch; then twist them together with the green wire provided on the dimmer, and cap with a wire connector. If you have a metal electrical switch box, be sure there is a pigtail ground wire connecting to the ground screw on the metal box from the ground wire splice.

Place the dimmer switch inside the switch box and replace the cover plate.