T-8 Question

[Jeffrey Schronce]

I put a bunch of T8 fixtures and bulbs in my shop. Last night it got really cold and when I went out there I noticed that most of the bulbs had "the wave" going on in them. I thought T8s were not supposed to do that? They did not hum.

[steve-norrell]

Jeff,

We have several different flourescent lights in the house and in the garage. When the garage is cold, it usually takes a little time (up to about one minute) for them to reach full brightness.

We also have some of those "energy efficient" flourscent flood lights and they also take severa second to reach full brightness.

Regards, SN

[LarryG]

I thought I knew the answer to this, but decided I'd better take time to call our electrical consultant and confirm. He said what I had thought: you have to make sure the fixture's ballast is designed for cold-weather operation. Most of the old magnetic ballasts in T-12s were only good down to about 45deg. The electronic ballasts typically used in T-8 fixtures are probably more likely to be cold-weather capable, usually down to 0deg, but this is not automatic just because you buy a T-8. I remember seeing both ratings when I was shopping for my T-8s, and made sure I got the ones that said they're good down to zero.

[steve-norrell]

Raises an interesting question . . . .

As I understand it, the ballast in tube-type fixtures is in the fixture itself, unsually inside the metal housing. The screw-in "energy-efficient' gadgets have electronic ballasts built into the base of bulb.

Am I correct? And, if so, then one has to be alert (or should be) for the cold-weather designator on the bulb packaging.

Thanks for the information. Regards, Steve

[Jeffrey Schronce]

I thought I knew the answer to this, but decided I'd better take time to call our electrical consultant and confirm. He said what I had thought: you have to make sure the fixture's ballast is designed for cold-weather operation. Most of the old magnetic ballasts in T-12s were only good down to about 45deg. The electronic ballasts typically used in T-8 fixtures are probably more likely to be cold-weather capable, usually down to 0deg, but this is not automatic just because you buy a T-8. I remember seeing both ratings when I was shopping for my T-8s, and made sure I got the ones that said they're good down to zero.

It is an electronic balast rated for down to 0 degrees. Now I am not sure how great the bulbs are that I have. Bought a case of them from Lowes. They are likely the problem. It will be interesting to see if they stop as they warm up.

[Tom Slick]

are they cheap fixtures? are they name brand bulbs?

[leehljp]

Here in Japan, I can tell a distinct difference in the start up of $8.00 bulbs versus $11/$12 bulbs. After a couple of minutes though, everything evens out fairly close. Only a critical eye can tell the difference after that.

If it is above around 70°, they start up and look the same.

[Jeffrey Schronce]

I can tell a distinct difference in the start up of $8.00 bulbs versus $11/$12 bulbs.

So I assume I should be able to tell a difference between my $1 bulbs and good ones? LOL!

Tom, they are cheap fixtures and cheap bulbs.

It is not a big problem, I was just suprized to see it happen.

[eccentrictinkerer]

This suggestion is not for the faint of heart. When it gets cold up here my garage/shop lights do the chasing/dim routine.

I keep a push-button propane torch on the shelf just for lighting up those chilly lamps (old ballasts - cheap lamps).

Just pass a low flame over the glass envelope of the lamp tubes and they light right up.. Something to do with warming the gases up so they can properly ionize.

[Tom Slick]

a good replacement T-8 ballast costs $20-25 so when you buy a fixture for about that price you know the quality isn't that great but not really a big deal.

[Hellrazor]

Jeffrey, My bet is the bulbs. Some will pulse like that and some will not. What brand are they?