Bookmark This Page

Delicious Google Bookmarks Stumbleupon Digg BlinkList Blogmarks Facebook Ma.gnolia Reddit Twitter Yahoo My Web Livejournal

Installing a Dimmer Switch

Dimmer switches are a great convenience. They help save electricity and allow you to adjust the atmosphere of a room. Sometimes you just don't want to be blasted in a pool of light. But many people are intimidated away from installing one where a standard switch already resides. Others have fluorescents and worry the dimmer won't operate properly. All those problems are easily solved.

Dimmer switches today come in a variety of styles, but two are still the most common: round and slide. They both work essentially the same way. They change the resistance of the circuit, altering the amount of current applied to the bulb.

That fact introduces the first possible problem. If the switch controls a fixture with a fluorescent bulb, ensure it's the type that can be dimmed. In years past, no fluorescent was capable, but the situation has changed in recent years. Many CFLs (Compact Fluorescent Lights), often used to replace incandescents today, can be dimmed within 80-20% of their normal output.

Once you're ready to go, the process is usually simple.

First, TURN OFF THE CIRCUIT BREAKER that controls the electrical supply that includes that switch. Never rely only on using gloves or 'being careful' to change a switch, though those are both good habits. Make sure you have the right one. Then make doubly sure by using a volt-amp meter to test that there really is no current at the switch.

It only takes 2/10ths of an amp to kill or do serious harm. Moist or salty hands can easily lower the body's resistance so that it takes only a few dozen volts to push it through you. Amps measure the amount of current, voltage is a measure of how 'hard' that current is pushed through the circuit. Watts = Volts x Amps.

From there on, the task is usually simplicity itself. Just unscrew the screws holding the faceplate on. Remove it and, with gloves on, pull the switch gently out of the hole. It will be attached by thick, difficult to move wires. Avoid yanking anything loose.

Then, unscrew the large wires from the old switch. Sometimes it's possible to just unscrew a plastic cap holding two thick wires together. More often, the thick copper wire will be attached to the switch by being looped around a screw post. Loosen the screw and slide the loop off the post.

Be sure to keep straight which wire was attached to which post. In many homes, the color coding is non-standard. It may differ from house to house. Though red and green or white and black are common colors for 'hot' and 'ground' the scheme is not universally respected.

Examine your dimmer switch or the directions it came with. Put the appropriate wires onto the appropriate terminals on the back. Wiring the switch backwards may allow it to still work, but it generates confusion. Down is typically lower, or less current. Ditto counter-clockwise is usually off. Getting them backwards is inconvenient, even when it still works.

Ensure that the wires are well separated, then turn the circuit breaker back on to test the switch. Make sure to keep your hands away from the wires. When the test is successful, turn off the circuit breaker and replace the whole assembly. Make sure no bare piece of wire touches another.

Done!