Hi. I have the long fluorescent lighting fictures in my den (2 long fluorescent bulbs per ficture). One of the fictures (both bulbs) are flickering... more like they are half on than flickering, kind of give off a grayish appearance. I put in 2 new bulbs but got the same issue. I installed a new ballast, same issue. Actually, when I installed the new ballast and cut the lights back on, the bulbs worked fine for about 5 minutes UNTIL I cut the lights off and cut them back on and then it went right back to "flickering" or appearing to be half on again. I even tried jiggling the bulbs back and forth to make sure they were making good contact on each side. Any ideas?

The fixture is not grounded properly, or the grounding wire to it is loose or broken.

Many times if there is a green or bare wire brought to the fixture is loose at the ground screw or not connected at all. The screw should be near the ballast or the wire is folded up near it.

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Originally Posted by tkrussell

The fixture is not grounded properly, or the grounding wire to it is loose or broken.

Many times if there is a green or bare wire brought to the fixture is loose at the ground screw or not connected at all. The screw should be near the ballast or the wire is folded up near it.

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Thanks for the quick reply! The ground wire is grounded at the fixture, however, I did not check to see how tight it was (although I'm assuming its fine because the ground wire is wrapped all the way around the ground screw). The ground screw is about 12 inches or more from the ballast... are you saying the distance from the ground to the ballast matters? Thanks again!

Could be the paint on the fixture causing the bad connection or not a machine screw, or the other end may not be grounded. or the ballast is loose.

The flickering is a typical symptom with fluorescent fixtures with a poor ground. The lamp starts by the capacitance of the glass tube and the grounded metal running the entire length of the tube. A poor ground metal pan affects the starting of the lamp. If the fixture is in sections be sure all tabs in slots are tight also.

If you have a volt tester you can check the ground by testing across the live black wire and the ground, and read 120 volts, also between the live black and the white at the ballast, and get 120 volts.