Installing dimmer switches is a relatively easy project even for the beginner diy electrician.
Dimmer switches come in two basic types, those designed to be used with incandescent lights and those designed to be used with fluorescent light fixtures. Incandescent dimmer switches can be used with any light fixture using incandescent light bulbs so long as the wattage rating of the dimmer switch is sufficient to handle the maximum lighting load it will be controlling. Fluorescent dimmer switches on the other hand are designed to be used only with fluorescent fixtures that incorporate electronic dimming ballasts, regular fluorescent fixtures with regular ballasts cannot be dimmed, neither can incandescent dimmers be used with fluorescent fixtures even if they have electronic ballast designed for use with dimmers. So the first thing that you have to keep in mind is to make sure that the dimmer switches that you purchase match the fixtures that you will be using them with.
Dimmer switches, like regular wall toggle switches come in two types, single-pole and three-pole configurations. Single-pole dimmer switches are used to control a light fixture from a single point. Three-way dimmer switches are used when control is needed from two separate locations. If you are replacing existing single-pole toggle switches with a single-pole dimmer switch or three-pole toggle switches with three-pole dimmer switches your main concern will be to ascertain whether there is adequate space in the existing devices box(es) for the dimmer switch(es). Dimmer switches are considerably more bulky then conventional toggle switched so you need to be sure that you can get them into the existing box(es) without forcing them. If the dimmer doesn’t fit, you will have to remove the old device box and install a larger box which goes beyond what I intend to cover in this factoid.
The wiring is relatively simple. Most dimmer switches, unlike toggle switches, come rewired with wire pigtails instead of screws or back-wiring holes. Three-way dimmers may have two red wires, a black wire and a green wire or one red wire, one white wire, one black wire and one green wire. The green wire is the grounding conductor and connected to the bare or green insulated conductor entering the box or to the metal device box itself. The two red pig tails or the red and the white pig tails are the traveler conductors and connect to the travelers that run between the device boxes. These travelers, if the house is wired with Romex will be red and white conductors with the white being identified as a current carrying conductor with black tape or black permanent marker. The black pigtail connects to the feed conductor and the switch leg conductors. You can identify the travelers when removing the old toggle switch because they are the ones attached to the brass colored screws, the feed and switch leg conductors are attached to the dark or black colored screws. Tag them with masking tape if you think it necessary and it doesn’t matter which traveler conductor connect to which traveler pigtail.
