# T8 Light problem



## FES (Dec 10, 2009)

I just changed out a T12 strip light with a T8 strip. The T8 lights up fine and within a few seconds the middle 1/3 of both bulbs turns a purple/redish color with a spiraling motion to the light. The ends of the bulbs are fine. I can cut it off for a minute and it will do the same. The supply house swears that I got bad bulbs and they replaced them....still the same. The voltage checks out fine and also the grounding is good. Any ideas???

Thanks-
FES


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## knowshorts (Jan 9, 2009)

If you leave the fixture on for a while, does the darker color go away?


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## FES (Dec 10, 2009)

I don't know...I only left it on for a short time. I'm going by this a.m. and will ck it. If not I picked up a replacement ballast from the supply house to put in???


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## Grimlock (Aug 4, 2009)

Did you replace the whole fixture or just the ballast? T12s and T8s use different tombstones.


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## Dennis Alwon (May 9, 2009)

Grimlock said:


> Did you replace the whole fixture or just the ballast? T12s and T8s use different tombstones.


I have never had to replace the tombstones when I converted from T12 to T8. I heard you must in some cases but not all.


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## oldman (Mar 30, 2007)

Leave the lights on for about 10-15 mins. Once they warm up, they'll be fine. 

Pretty common actually


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## user4818 (Jan 15, 2009)

oldman said:


> Leave the lights on for about 10-15 mins. Once they warm up, they'll be fine.
> 
> Pretty common actually



Yeah, I agree. Commonly referred to as "burn in" which is the opposite of what most electricians do which is "burn out". :laughing:


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## knowshorts (Jan 9, 2009)

Yeah, they take some time for the gases to get exited, and to get to full brightness. 

Work is a little slow, and I am forced to do lighting maintenance, and I have noticed quite a few bad lamps with a orangish half. Never seen T-8s do that before.


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## FES (Dec 10, 2009)

The entire fixture was changed out. Went by today and swapped the ballast just to be on the safe side....same thing happened though. 

As far as leaving them on for a while....I just replaced about 20 fixtures with the same T8 and they all come on and stay on and did so from the get go???

I talked to an engineer with the ballast co. and he said it was in the bulb and to leave on for a little while....who knows???


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## McClary’s Electrical (Feb 21, 2009)

FES said:


> The entire fixture was changed out. Went by today and swapped the ballast just to be on the safe side....same thing happened though.
> 
> As far as leaving them on for a while....I just replaced about 20 fixtures with the same T8 and they all come on and stay on and did so from the get go???
> 
> I talked to an engineer with the ballast co. and he said it was in the bulb and to leave on for a little while....who knows???


 

That's strange you replaced 20 that did not do it. Because I've replace 1000's of tubes and almost every tube requires a burn in time before it actually looks right. It's getting the gases to the perfect pressure. Once burn in, they'll light bright every time. You'll only see it the first time you cut it on, for the first hour or so. After that you're good.


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