Why do ballasts hum

That 4-foot, two-lamp fixture in your garage or basement, for example, likely uses T12 lamps and a matching electromagnetic ballast, says Jeff Goldstein of Lamar Lighting in East Farmingdale, N. Electronic ballasts are standard on newer T8 fixtures, according to Goldstein, but it might be more difficult to find them for older T12 lights. Also consider the location of the fixture. Standard ballasts work best in temperatures above 50 degrees.

If lamps are in colder areas, buy cold-weather ballasts, which can fire up the lamps in temperatures as low as zero. To remove the ballast, cut power to the circuit at the circuit breaker panel. Take out the lamps, then remove the access panel on the fixture and disconnect the black and white wires from the power supply.

Next, clip the three pairs of wires emerging from the ballast; there should be two reds, two blues and two yellows. Reconnect leads on the new ballast with wire nuts; the light should work fine once again. Most residential fixtures use magnetic ballasts that operate at 60 hertz, which creates audible humming and flickering. Your solution is to replace the magnetic ballast with electronic ballast, which operates at 20, to 40, hertz, essentially continuously. This completely eliminates humming and flickering.

The electronic ballasts only work with the new thinner diameter fluorescent tubes, called T-8s. If you convert your fixture to electronic ballasts and T-8 lamps, you will notice a huge improvement in quality.

Flickering fluorescent lights are caused by the starter not being able to fire gas into the tubes. You will need to remove the bulb to get to the starter, which is a round plug sticking out through a hole.

Fluorescent lights really only have two parts -- the tube and the ballast. This means a new ballast is really the only repair you'll need to make to fix a humming bulb. If you have flickering or continued issues, check the sockets or wire connections.

A bad or loose connection may be the culprit. If you have electronic ballasts, check the ground wire. Finally, try replacing the light. They are cheap and easy to swap out. Did you know you can get expert answers for this article? Unlock expert answers by supporting wikiHow. Ralph Childers Electrical Professional. Ralph Childers. Support wikiHow by unlocking this expert answer. Yes No. Not Helpful 0 Helpful 0. Include your email address to get a message when this question is answered.

By using this service, some information may be shared with YouTube. Make sure to purchase a ballast for the number of lamps in the fixture, and that the bulbs are compatible with the ballasts. Helpful 0 Not Helpful 0. Don't open the case until you are certain that the power is off. Helpful 4 Not Helpful 2.

Helpful 0 Not Helpful 1. Old T12 fluorescent bulbs contain mercury, so be sure you dispose of it properly. Related wikiHows How to. How to. About This Article. Co-authored by:. Co-authors: Updated: August 10, Categories: Lighting. Thanks to all authors for creating a page that has been read , times. Reader Success Stories D. Tsurymoto Jul 26, I was scared to replace it without some basic instructions. The article said to go ahead and cut the wires then use connectors to reattach , which is what I was unsure of.

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