I have a fluorescent light fixture in my kitchen, which uses u-shaped tubes.

A few weeks ago they just stopped working. I could turn the switch on and there'd just be no light. Not flickering which I've read indicates a bad bulb. No buzzing sound, which I read means the ballast is bad either.

To make things weirder, a couple days ago I absent mindedly flicked the switch and the lights came right on! Today they worked fine when I got home from work, but after cooking I turned the lights off... when I tried to turn them on again an hour or so later they wouldn't come back on.

So what could be causing this?

EDIT: I should note that I installed new bulbs and they didn't work until the other day... and now they've stopped again.

3 Answers 3

  1. Confirm your wall switch is good. Bad switches can be intermittent.
  2. Turn off the switch and take the tubes back out and put them back in making sure they're fully snapped in. It's worth a try. Don't go buy more, but if you have other new tubes try them.
  3. If the lights work for a period of time and go out on their own, that usually indicates an over-heating ballast - replace the ballast.
  4. Otherwise, the best test for a ballast is just what you did, try new tubes. If no luck, replace the ballast.
  5. While replacing the ballast, make sure all of the wires in the sockets are well connected. Give them each a little tug. If you can't get a wire to stay in a socket replace the socket, maybe replace all 4.
  6. Fluorescent lights need to be grounded to work properly. Make sure a ground wire is attached to the fixture. I've seen fluorescent lights, especially in old homes, where the people say they're always replacing tubes, and it's because the fixture isn't grounded.
  7. If you're going to replace the ballast or the entire fixture consider going with an electronic ballast maybe even T8 size tubes. Amazon sells the smaller clips you'd need for a retrofit to T8 U-Bent tubes - ASIN B00A3WGR0W.
  • Just had a friend who does this stuff look at it, pretty much agrees. Recommended I replace the entire fixture...
    – CodeRedick
    Commented Dec 3, 2014 at 17:05
  • I would switch to LED , but it could be a bad switch , not likely, more likely the ballast.
    – Ed Beal
    Commented Oct 12, 2017 at 22:48

Bulbs nearing end-of-life.

Ballast nearing end-of-life.

The CFL in my office has been doing something similar for months - I just turn it on once a day and try to remember not to turn it off unless it will be off for hours. It's a normal failure mode for fluorescents. Buzzing and flickering not required.


Depending on the type of light you have your may have starters which precharge your light. If these are malfunctioning the light will not turn on or may turn on at random times. The starters will be a small component which you push in and turn counterclockwise to move. It usually appears under the shield of your light. they are less than a dollar usually at a local hardware store to replace. Typically, if a ballast is going out you will have signs of flickering (at a slow rate) buzzing etc... Before spending big money on a ballast see if you have a starter on your light.

  • I repair a lot of fixtures, with the electronic ballast there may be no warning and they may start intermittently with good lamps. I miss the old mag ballast they last forever but can cause a fire more easily than an electronic ballast.
    – Ed Beal
    Commented Oct 12, 2017 at 22:52

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