New T8 lights failing after a few hours - bulbs or fixture?


estesbubba

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I'm putting up 8' four-light high output fixtures from Home Depot and so far have 6 of them up. On one fixture 2 different lights have failed in different positions. I bought a 30 pack of Philips 850 series 5000K bulbs so guessing they are from the same batch. None of the other fixtures or bulbs are having this problem and the other 2 bulbs in that fixture are fine so far. 

 

Don't know if this could be just some bad bulbs or a bad fixture (ballast). In all my research I didn't see special T8 bulbs needed for high output ballasts. 

 

BTW - the fixtures have 2 pin connectors .

Edited by estesbubba
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If some of the bulbs in the fixture are working it's not the ballast. So that narrows it down to the bulbs or, the receptacle take one of the bulbs that work put it into one of the receptacles that don't work if the bulb lights up it's the bulb if not than it's the receptacle. If the receptacle's not working take the bulbs out take the dust cover off check the connections if you have a tester check to see if your getting power where the pig tails connect to the ballast if so go buy some more pigtails from HD your back in buisiness.

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T-8’s have electronic ballasts.  It is common for the OEM of the fixture to use the cheapest they can get so yes, you could be suffering from pre mature failure.  Check to be sure the lamp is matched to the ballast, size (T-8 means one inch, lamps are in 1/8”) check for lamp wattage as well, check output (standard HO, VHO…I doubt this is wrong but….).  Make sure the pins are seated correctly.  There is a dimple in the metal end of the lamp that will be centered in the socket.  With electronic ballasts it is possible to have a partial working fixture.  The wires feeding the sockets could also be loose.  Check them but it is possible if they were/ are loose you could have still fried part of the ballast.

Don’t be surprised if the fixtures start to go out in a pattern, I can’t explain it but have seen it often enough.

Oh, I didn’t mention electrical safety….I figure you have that covered. :)

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When I redid my shop lighting with T-8's 4 years ago, my initial install used three boxes of Phillips Alto II bulbs, with the green ends on the tubes, from two local Home Depot locations.  I was not at all impressed with the life of those bulbs.   I had more than a few die quickly, some lasted longer, but still died in the next few months, and a few still work after 4 years.  

 

I'm not imagining the life spans, as I mark the installation date on tubes with a Sharpie.   I've yet to lose a ballast, and the failures didn't happen in the same fixtures or positions...

 

After the initial run of failed Phillips tubes, I've switched to Sylvania bulbs with much better results.   Both versions of tube have identical specs on the box.

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Well I bought 40 Sylvania FO32/850/ECO which are 800 series and 5000K temperature and had them in 2 fixtures for a couple of hours and so far no problems. I did notice that the Philips bulbs are a little warmer in the fixture than the Sylvanias. Philips are $43 per 10-pack at Home Depot and I got the Sylvanias at almost 1/2 off at $2.20 per bulb at electrical supply house. Specs are about the same with the Sylvania 100 lumens brighter and 2 CRI less - my eyes can't tell the difference looking at them in the fixtures. So far the Sylvanias haven't turned black at the ends but maybe they all do over time. 

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Mixed in the same fixtures, I can't tell which bulbs are from which manufacturer unless I pull the diffuser off and look for green ends.    Except the Sylvania bulbs don't fail in six minutes...

After about 15 hours of run time no problems with the Sylvanias. They are brighter and guessing they play better with HO ballasts as 100 lumens isn't much more. They also have consistent color the length of the tube and no black ends like the Alto II bulbs had. Oh and 1/2 the price is nice!

Thanks for the advice Barry.

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