Single Fluorescent Light Wiring Instructions

Updated February 21, 2017

Fluorescent lights have been around for decades and are normally associated with office buildings, schools and the occasional workshop. In fluorescent bulbs, electric current flows through a coated tube containing argon and mercury, excites the gases and causes the coating to glow. Newer fluorescent lights are more energy-efficient than incandescent bulbs and are becoming more commonplace in home decor. Wiring fluorescent fixtures is no different than traditional fixtures, although the interior of the lamp is radically different.

Wiring Fluorescent Fixtures

The key to using fluorescent fixtures--not just fluorescent bulbs in a traditional fixture--is the power draw on the circuit. Like an electric motor, the ballast inside the light can cause a power surge in a circuit when it is turned on. If the temporary surge puts sufficient strain on the circuit, the breaker will trip. To avoid this problem, make sure the circuit where you will be adding the fixture will not be overloaded.

If the circuit can handle the extra amperage of the ballast, wire it just like any other electrical circuit. The easiest way is to tap into a circuit through a receptacle, run the cable to the light fixture, then run the cable to the switch. Like any other fixture, fluorescent lights can be wired into a three-way circuit, where the light is controlled by two switches located at different points in the room.

You can use dimmer switches with fluorescent lights, but they require special ballasts. If the fixture instructions do not indicate that you can use a dimmer switch, you will probably have to replace the ballast to do so.

Maintaining Fluorescent Fixtures

Fluorescent lights require increased voltage to operate correctly. Inside the fixture is a ballast, or transformer, that increases the voltage from the normal 120 volts of household current. Like any electrical appliance, ballasts fail and must be replaced. If your fixture does not contain a starter, you know the bulbs are good, but if the light does not work, the ballast has likely failed. The annoying humming sound associated with florescent bulbs is a signal that the ballast is failing.

In older fixtures with starters--a small button-like device near the bulbs--flickering lights are indicators that either the bulb or starter is failing. If the ends of the tube are particularly dark, chances are the bulb is failing. If the lights flicker but do not fully light, check the starter. Newer fixtures do not contain starters.

Replacing a ballast is not difficult, although there are numerous wires to disconnect and reconnect. Fortunately, there are standard colours for fluorescent light wires (blue, red, white and yellow), and each ballast comes with a wiring diagram. The only tool necessary for ballast replacement is a flathead screwdriver.

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About the Author

Mark C. Gribben is a writer living near Columbus, Ohio who is a nationally recognized crime historian. Gribben earned his Master's degree in public administration from Michigan State University in 1998.