T8 4' fixture - sometimes bulbs go out - twist them and they come on


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Old 10-11-13, 05:04 AM
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T8 4' fixture - sometimes bulbs go out - twist them and they come on

I was just wondering why this occurs. I've got two 4' T8 fixtures in my shop and it seems (I'll have to start writing the date on the tube when I replace it) like I have replaced them all once so far and I've only had the fixtures installed for a year, maybe a year and a half at the most.

Anyhow, what I notice is that one of the bulbs will be off while the other is on. The tips of the the bulb which is out are not very black like they get when they are bad. All I have to do is twist the bulb a little and it comes on. Next time I enter the shop and turn the lights on, same thing. That bulb is out - twist it and it comes on.

Ideas?
 
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Old 10-11-13, 07:00 AM
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I had cheap 4 foot fixtures in my garage and gave up on them and installed CFLs. Never could keep all the bulbs lit. Maybe the better fixtures would have worked.
 
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Old 10-11-13, 08:37 AM
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Do they have a good ground:
 
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Old 10-11-13, 09:08 AM
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As far as I know. The ballast ground is connected to the Romex ground. What's the best way to check for a "good" ground?
 
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Old 10-20-13, 12:59 PM
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Do you have the correct ballast in the fixtures?
T8 tubes need a T8 ballast. Also I once ran into a wiring job where the dude had two 2 tube fixtures back to back and tried running them off a single 2 tube ballast. I gather you have 4 tubes? Make sure each fixture has its own 2 tube ballast, or if they are side by side that a 4 tube ballast is correctly wired and running them.
 
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Old 10-20-13, 01:32 PM
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Those are most likely standard/magnetic ballasts. New style electronic ballasts do not require an intact filament and will work with just one pin connected.
 
 

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