Florescent Lights not very bright

Old 12-27-02, 01:07 PM
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Florescent Lights not very bright

I just installed two florescent light fixtures in my mother's basement. Each fixture came with 1 balast, was 4' long with 2 40W tubes. I installed them to replace a couple existing incandesant type of lights. The house is around 50 years old and the existing wiring consisted of only 2 wires (black & white, no ground on a 15A circuit) There are other lights and outlets on that same circuit, but not very much.

I ran new 14G romex w/ ground between the two fixtures. I attached the ground wire of the new romex to the green grounding screws, but also wrote with marker within the fixtures next to the groung screw, "Not Grounded to Panel". Power source to the first fixture was the existing old 14G two wire cable, no ground. Simple Black to Black, White to White, each wirenutted together.

Why is the light output so dim / poor? These are standard, $20.00 light fixtures, and I made sure the bulbs (tubes) were standard 40W. It is like they are at half power. I bought two new different bulbs (tubes) and installed them, no change.

Your suggestions / help is greatly appreciated. Thanks Mike
Old 12-27-02, 03:28 PM
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There is a number of things that can cause this, do you have a meter to make sure there is enough voltage getting to the fixtures in the first place, low voltage can result in dim lamps?
Next the lamps you are using you say they are standard 40W what is the numbering on them?
Next are both the fixtures about the same brightness or is one brighter then the other?
Check your connections especially at the ballast make sure the lamps are in tight and not loose.

Let me know what you find please
Old 12-27-02, 03:34 PM
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And what's the temperature in that basement?
And do they get any brighter if you leave them on for hours?
Old 12-28-02, 06:16 AM
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Could be because the housings aren't grounded. Some fixture ballests say mount lamps within 1/2" of a grounded metal housing.

Also check that your hot wire is the hot and not reversed. I've had lights not light properly when bench testing them and I've reversed the wires when I've stabbed them into an extension cord.

Also John and Guards responces are common problems

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