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Switching to Dimmers


Replacing an existing light switch with a dimmer allows you to adjust the illumination in a room, and it's about a 10-minute project, even for a novice.

Dimmer switches come in a three common designs: rotary knob, slide bar and toggle.

The rotary knob dimmer allows you to control the light by turning a knob. The slide bar design works the same way but the light level is controlled by sliding a horizontal bar. The toggle dimmer looks like an ordinary wall switch light and is controlled by simply moving the toggle up or down.

Whatever type you select, make sure it can handle the wattage of the circuit it will control.

Prepare to remove the existing wall switch by turning off the power to the room by flipping the breaker at your electric panel. Remove the switch plate by taking out the screws and then do the same for the existing switch. Pull the switch out of the box as far as the wires will allow. You should see two wires connected to the back or side of the switch.Carefully remove the wires from the existing switch by unscrewing the side terminal screws or by pushing a small, thin screwdriver into the wire release holes.

If needed, straighten the ends of the wires and/or strip off insulation so that about five-eighths of an inch of bare copper is showing.

The new dimmer switch also has two wires coming from it that will connect to the two wires in the wall. You will use the plastic "wire nuts" to connect the wires. Make sure the dimmer wires are also stripped to show about five-eighths of an inch of bare copper. With pliers, twist the ends of a dimmer wire and a wall wire together and thread a plastic wire nut over the pair so that it seats tightly. Do the same for the other pair of wires. Wrap electrical tape over the connection between the wires and nut.

Carefully install the dimmer switch into the wall box and secure it in place with the two screws from the old switch. Reinstall the plate and flip the breaker back on.


Gary Abrams is a general contractor who has written about home improvement for The Times for 10 years. Questions can be sent to him at

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