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Old 12-03-2014, 05:33 PM
stanger is online now
Join Date: Dec 2004
Location: San Antonio, Texas
Posts: 584

Fluorescent light erratic starting problems

I have numerous double-bulb fluorescent light fixtures in my home, and as far as I can tell, they were installed in 1968. I believe the ballast was replaced in the kitchen light several years ago.

For the most part, they have operated fine in all this time - but when it rains, and the humidity is very high - they will not start up. You can see the ends glow a bit, and sometimes you can flip the switch back and forth a bit and get them to come on, but they usually won't light up.

The five lamps in the garage are this way, as is the one in the kitchen. I have changed out bulbs, but it doesn't help. If it is a rainy day, the lights may start up slow or with a little prompting the first few hours, but as the day progresses, they will not fire up. Really cold weather also can sometimes add to the problem.

These lights have been this way for many years, and it isn't much of a problem, but it is irritating.

Is this just a matter of a ballast replacement?
Old 12-03-2014, 06:19 PM
Crafter_Man's Avatar
Crafter_Man is offline
Join Date: Apr 1999
Location: Ohio
Posts: 11,275
Your house wiring... are all circuits hot/neutral/ground, or hot/neutral?

Just a WAG, but on some fluorescent light fixtures, it is necessary for the steel reflector (the white sheet metal behind the bulbs) to be electrically connected to "ground" via a ground wire between the fixture and circuit breaker panel. At start up, a small amount of current must flow between the bulbs and reflector (through capacitive coupling) to get the bulbs to fully energize. If your fixtures are of this type, and if the reflectors are not connected to ground, then that's your problem.
Old 12-04-2014, 04:28 PM
stanger is online now
Join Date: Dec 2004
Location: San Antonio, Texas
Posts: 584
I am not sure about the hookup, but all the receptacles in the house are 3-prong, if that makes a difference.

None of the fixtures in the garage have had any reflectors on them. They have always been just the white rectangular box with the bare bulbs underneath.
Old 12-04-2014, 04:47 PM
johnpost is offline
Join Date: Jul 2009
Posts: 12,056
it is right about needing close grounding on some fixtures. where there is a reflector it has to be grounded well, but it is also removable to access the wiring and may have gotten a poor ground through movement or corrosion. if these fixtures don't have a reflector, but still need a nearby grounded metal, the ground could have failed to the fixture.


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