Latest Discussions : Electrical & Lighting


12:50PM | 03/07/08
Member Since: 03/06/08
3 lifetime posts
I'm putting together a lighted sign for a friend's business. We have seven 8 Ft, 2 Lamp, High Output/Cold Weather Fluorescent Strip Light fixtures we are putting inside of a big metal box with an acrylic face. I have everything mounted in the big box, all wired together and grounded CORRECTLY. But at the moment when I was expecting a glorious bright glow from the first strip I put the bulbs into, I was crushed to see the bulbs were really dim in the center. why would this be? Is this common among 8 ft bulbs? Is the wiring in his garage where I am working on this not properly grounded? I know that when I have only one bulb on a strip, that bulb is very dim, but increases about three times in brightness when I put the other one in. We only have the two bulbs to test with right now, since he is an ass and refusing to buy more until I "figure out what I did wrong". But could this same phenomenon apply with regards to the whole project? ie; if I put bulbs in the next fixture up, will it then cause a little boost in the dim ones? Please help me somebody. Although he's had this freakin thing sitting in his garage for the past year and done nothing with it, he is getting really upset with ME for not having it done now...


04:50PM | 03/07/08
Member Since: 04/25/05
1915 lifetime posts
The ballast(s) have to be matched to the type and number of bulbs.

With sometimes of ballast the fixture won't work right if all sockets are not filled with good bulbs.

Look at the label on the ballast and see if they are for the HO bulbs.


07:50PM | 03/07/08
Member Since: 01/09/07
199 lifetime posts
Dimming or darkening is a common sign of a florescent tube that is about to burn out. Most commonly, this appears toward the ends of the tube, but it could happen in the middle.

The easy way to test for this it to buy a couple of new tubes, and try them in the fixture.

If this has been going on for a year, buy the tubes yourself, and try them out. When they work fine, tell this ass you are working with the problem with the other tubes is that they are about worn out. Then give him the receipt for the tubes you bought, so he can reimburse you.


12:17AM | 03/08/08
Member Since: 03/06/08
3 lifetime posts
Tim, I meant the sign has been sitting, unassembled in his garage for a year. ;) I only just very recently mounted the fixtures and did the wiring. The tubes are brand new. Purchased less than a week ago. Thanks though Tim.

And Bill, I'm quite certain he got HO tubes. Granted, I am not POSITIVE. So I'll be sure to check that out when I head over there in the morning.

Is there even a slight chance that this has anything to do with our ridiculously cold Michigan temperature? I mean, I left them on to "warm up" for quite some time. Is there a chance that I just didn't have enough patience? I can't imagine this to be the case. I've suffered through our winters here all my life and have never experienced having to wait for the fluorescent lights to warm up in our garage. And the fixtures even claim to start at 20 below. Figured I'd throw that cold theory out there...

About the theory I have that I may need to put tubes in the other fixtures: would that make ANY sense at all?

Thanks again for any and all help everybody!

doug seibert

06:27AM | 03/08/08
Member Since: 08/10/02
842 lifetime posts
Is this acrylic on both sides ?

The signs I've worked on have Grounded straps very close/next to each tube for the the lamp to strike..........

"...measure once.....cut twice....throw that one away and cut a new one...."

Tom O

03:48PM | 03/11/08
Member Since: 09/17/02
476 lifetime posts
By any chance, are you using electronic ballasts with T8 lamps? The T8 means the lamps are 1" in diameter as opposed to the older T12 (1 1/2" diameter). If you are using the T8 lamps, light them for a few hours and the dim middle will go away. This seems to be a characteristic of 8 foot T8 lamps.


02:04PM | 03/14/08
Member Since: 03/06/08
3 lifetime posts
i have t12 ballasts and t12 lamps. turns out the problem was just bad lamps. went back to home depot and purchased a few more lamps. same problem! with my head about to explode, i took one of the fixtures i had mounted out of the sign and took all of my bulbs to a local electrician's shop and told them they need to test everything for me. they were dim there too. tried two tubes out of their shop. and they lit brilliantly. turns out it was just a bad box of lamps from home depot. so i bought the lamps from these guys and promptly returned the bad ones to home depot and let them know they should test the rest of the shipment they got.


11:57AM | 05/04/16
I see the same thing when I am changing my old t12 fixtures over to T8. The bulbs are dim in the middle the first time the light bis turned on but after a couple hrs they get bright and stay bright.

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