Fluorescent lamps fluctuate in brightness

[JJBarnes]

We have some cove mounted fluorescent fixtures that the brightness fluctuates. It is not a flicker like a bad lamp does. I was told that the Electrical Manager before me tried to correct it but never solved the problem. I haven't had an opportunity the check them yet as they are cove mounted up about 25-30'. Has anyone else seen this before or have an idea what could cause this?

Jeff

 

[jeremysterling]

Cold air from a draft or air conditioning duct could cause fluctuations.

 

[Mr. Bill]

Check for voltage fluctuations.

 

[sbecker]

sbecker

sbecker

Check for compatibility between lamp and ballast. Some T8 ballasts ( if thats what they are) are not compatible with newer energy saving lamps. Low mercury content in the lamps will cause flucuation and styration, a wave effect running up and down the lamps. Also some ballasts are just not compatible with certain (cheaper) lamp manyfacturer's lamps.

 

[LarryFine]

What kind of flicker? Steady like a strobe, or intermittent.

I've seen lighting-like swirling and zebra-striping.

Do they all do it? Could be a supply issue.

If only one or two, could be ballasts.

 

[JJBarnes]

Thanks for the input guys. The problem turned out to be incompatable ballast and lamps. One of the electricians admits to installing T-5 lamps on fixtures with T-8 ballast. Why does it seem like there is not enough time to do the job right the 1st time but there is always enough time to go back and do it over?

Jeff

 

[boboelectric]

I never used t-5 s,but understood they weren't 48" We once used t-8 lamps instead of t-12 s,and they strobed about an hour after we left.