# T8 Ballast



## noarcflash (Sep 14, 2011)

I replaced so many T8 ballasts in the past 2 weeks.. it is totally ridiculous. All brands, they just fail.

However, I think I am noticing a trend, but I am not sure. There are usually less than 4 lamps in the fixtures. and these are the ones I see failing ...

Could this be the reason ?????
the ballast is designed for 4 lamps, and when the customer only burns 2 or 3 lamps, the ballast is more prone to failing ????


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## erics37 (May 7, 2009)

Yeah I've noticed that too, the ballast doesn't like being off-balanced or something. I don't have any more technical explanation for it, but I've observed the same thing.

I stick to Phillips Advance ballasts and so far I haven't had to replace one. I've replaced lots of Sylvanias, LOTS AND LOTS of TCP ballasts, lots of Caster ballasts from Korea... and of course lots of really old ballasts from all makes.

But I do notice that fluorescent light problems seem to come in waves. I'll have nothing for a while and then it seems like every ballast in the county fails at once.


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## crazyboy (Nov 8, 2008)

I've noticed the same thing, which leaves me wondering how using a 4 light ballast for a 3 light fixture, and a 2 for a one works.


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## erics37 (May 7, 2009)

crazyboy said:


> I've noticed the same thing, which leaves me wondering how using a 4 light ballast for a 3 light fixture, and a 2 for a one works.


It works, but as noted, the ballast seems to fail a lot sooner than normal, almost invariably.

EDIT: This might only apply to Instant Start electronic ballasts, which could explain why they fail sooner. If they're trying to high voltage instant start a lamp that's not there, it could burn up the ignition circuitry quicker. Those are the ballasts I usually install.


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## user4818 (Jan 15, 2009)

Is it true that leaving a burned out lamp in the fixture for extended lengths of time will shorten ballast life? 

Regarding electronic ballasts, I think 5-10 years is about their life span in my observations. They're basically a cheap circuit board in a metal box subject to constant heat. It's no wonder they fail.


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## erics37 (May 7, 2009)

Peter D said:


> Is it true that leaving a burned out lamp in the fixture for extended lengths of time will shorten ballast life?
> 
> Regarding electronic ballasts, I think 5-10 years is about their life span in my observations. They're basically a cheap circuit board in a metal box subject to constant heat. It's no wonder they fail.


Don't know if you've come across this document before, but it's pretty handy.

Pocket Guide to Fluorescent Lamp Ballasts


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## user4818 (Jan 15, 2009)

erics37 said:


> Don't know if you've come across this document before, but it's pretty handy.
> 
> Pocket Guide to Fluorescent Lamp Ballasts



Thanks, I just printed that out. :thumbsup:


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