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Changing a Fluorescent Light Fixture Ballast

By Dave Rongey - Summary:

How to Replace a Light Fixture Ballast: How to Make Your Fluorescent Light Fixture Last Longer and Avoid Burning Out the Expensive Ballast

How to Make Your Fluorescent Light Ballast Last Longer

Electrical Question: My florescent light went out over my bathroom sink.

I know zero about electrical matters and wonder how that could happen?
Please advise – Thanks

This electrical question came from: Ken, a Homeowner from Pickens, South Carolina.

Additional Comments: This is the first time I have seen your web site.

Dave’s Reply:
Thanks for your electrical question Ken.

Replacing a Fixture Ballast

Application: Replacing a Fluorescent Light Fixture Ballast.
Skill Level: Beginner to Intermediate.
Tools Required: Basic Hand Tools and Safe Ladder.
Estimated Time: Depends on personal experience, the light fixture and access to the light fixture.
Precaution: Identify the light fixture circuit, turn it OFF and Tag it with a Note before working with the wiring.
Notice: Replacement parts for the light fixture should be compatible with the type of fluorescent lamps that have been installed.

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4 Responses to “Changing a Fluorescent Light Fixture Ballast”
  1. Dave Rongey says:

    Hi Terry,
    Sorry to hear about the problem with the power outage and generator. I have seen the same thing happen, and what we concluded was that the voltage from the generator fluctuated because it was powering up other devices that turned On at the same time which pulled down the voltage. When the voltage drops it causes power supplies such as the ballast to overheat. Having a good brand power strip will protect whatever is plugged in to the point of self destruct. The voltage that you have stated is in the safe zone, but it must be steady and the 60 cycles or hertz must be right as well.
    I highly recommend generators that are sized appropriately and have electronic voltage regulators.
    I hope your fish are OK.

  2. Terry Staph says:


    During the recent power outage I used a generator to power my fish tanks. The result was two burned out power strips ( one actually burned ) and two burned out ballasts in the aquarium light fixtures. I checked the generator voltage and it was between 117-125.

    What caused the problems??



  3. Dave Rongey says:

    Yes Al,
    The two pin florescent lamp sockets are compatible for both T12 and T8 Lamps, the only difference may be the height of the socket.
    FYI – these sockets may be purchased from your local hardware store.


  4. Al says:

    Sorry, don’t know the correct verbage. My bathroom florescent fixture is a 2-light type and has one broken socket at one end of one of the lights. I have another model workshop florescent fixture. Could I just use one socket from it to replace the broken one. Worse case, can I use the work light ballast RS lamp to replace the bath one?

    Bath: Two F40W T12 RS lamp (120V. 60 Hertz)

    Work Light: Two F40 430 Mars lamp (120V, 60 Hertz) or two 4FT 34W/35w RS-lamp 460 MA Max

    Thank you!