We just replaced approx. 30 flourescent 2x2 fixtures with new 2x2 ( 3 17W T8). All the lamps are flickering ?????? We have the right voltage to nuetral and ground as well and there was no problems w/ the previous fixtures. Any suggestions why the lights are flickering ????????????
Flourescent Light Problem
- Thread starter adavey
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Is there any difference in the wattage (i.e., what was the wattage of the old fixture)? Is there any difference in the type of ballast?
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
I assume, by "replace", you mean that all the fixtures you installed are new, with new lamps.
"Flicker" is a little non-specific.
One possible flicker happens in the initial 300 to 600 hours that a lamp runs. The arc will gutter inside the tube resulting in an irregular, moving, twisting bright stripe spiraling along the fluorescent coating of the tube.
In many lamps, this is normal and dissappears with a little age.
"Flicker" is a little non-specific.
One possible flicker happens in the initial 300 to 600 hours that a lamp runs. The arc will gutter inside the tube resulting in an irregular, moving, twisting bright stripe spiraling along the fluorescent coating of the tube.
In many lamps, this is normal and dissappears with a little age.
We relaced the whole fixture. New ballasts are dual rated 120V-277V. The lamps we used comply w/ the lamp listing on the ballasts. It flickers so bad you think a "strobe" is going off.
We called the manufacturer and he came on site to inspect the problem. He had no idea as well. However, he said he would replace all the fixtures w/ new ballasts. I could see 1 or 2 ballasts go bad, but not 30+
We called the manufacturer and he came on site to inspect the problem. He had no idea as well. However, he said he would replace all the fixtures w/ new ballasts. I could see 1 or 2 ballasts go bad, but not 30+
Kessler4130
Senior Member
- Location
- Maryland
I have seen issues like this using shared neutrals on 277 volt flourescent lighting, that could be the cause of this but I certainly hope not 
. Alot of commercial/industrial applications now use seperate neutrals or sometimes even "super" neutrals (10 awg neutral with 12 awg circuit) for all thier 277 volt lighting.
. Alot of commercial/industrial applications now use seperate neutrals or sometimes even "super" neutrals (10 awg neutral with 12 awg circuit) for all thier 277 volt lighting.Kessler4130
Senior Member
- Location
- Maryland
adavey said:
Honestly I have no idea, I just install what you engineers design. All I can offer is a theory with out actually seeing the lights myself. The times I saw it derived from a neutral issue it was more of a strobe effect than that of a flicker, more like the light was on and off not just low and high. Now in one case it was 3 lighting ckt's 3 seperate neutrals and the neutrals got swapped in a JBOX in the middle of a run. So for the sake of arguement lets just say the ckt was intended to be A "277v flourescent" B "277v flourescent" and C "277v Exit lights and wall packs". Well B and C traded neutrals and that was the cause of the problem.
How or what caused it was the swapped neutrals, why it does that ? Well that I cannot answer, I would let someone with an engineering backround field that one.
77401
Banned
I had a simular issue.
New lease space... Sylvania 120v 4 lamp t-8's all went bad in just months.
I called Sylvania & they sent new ballasts for everything but refused to cover labor charges.
I can only assume they are aware of a munufacturing defect
New lease space... Sylvania 120v 4 lamp t-8's all went bad in just months.
I called Sylvania & they sent new ballasts for everything but refused to cover labor charges.
I can only assume they are aware of a munufacturing defect
jeffhornsby
Member
- Location
- Destin, FL
I seriously doubt it is harmonics if you want to check and do not have any testing equipment that analyzes harmonics use a ammeter and see if your neutral reading is higher than your hots, even with a higher reading I am not sure it would cause that.
It must be an existing building since you replaced the lights. If the original contractor used the conduit as the grounding condutor test voltage between the hot and the frame of the ballast.
If the lights are installed in area where the ambient temp is less than 50 F that can cause that effect unless the ballast is rated for low temp.
It must be an existing building since you replaced the lights. If the original contractor used the conduit as the grounding condutor test voltage between the hot and the frame of the ballast.
If the lights are installed in area where the ambient temp is less than 50 F that can cause that effect unless the ballast is rated for low temp.
I replaced 4 (120V) fixtures for a customer in his garage. 3 of the 4 flickered on and off (like a strobe as you say). After checking the circuit, I switched the ballast from the working light to one of the others, and it worked. I then looked closer at the ballasts, and the 3 that didn't work were rated for 277V (not dual rated). The box that they came in said the fixtures were 120V! I won't give the brand, but it rhymes with a northern state.
Re-check the ballasts.
steve
Re-check the ballasts.
steve
We installed new ballasts from Sylvania (Dual Voltage Rating) and the flicker problem is fixed. I've never seen a batch of bad ballasts before (luckily it was only thirty +). I still don't know why the electrician kept putting them up when they didn't work properly ????????? I guess now the electrician is getting paid twice.
hockeyoligist2
Senior Member
- Location
- close to greenville sc
adavey said:
He probably figured they would stop flickering. I have put in a lot, especially in the winter, where they were real cold from being on the truck. and they flickered about an hour or so then they were ok!
haskindm said:
A project was just recently completed. After looking across the ceiling at the recessed lights (lithonia avante style lights), most had a yellowish color. But some of the lights were notably bluer. I thought they had used different lamps in those fixtures. The electrician pointed out that every light that was bluer was right next to a supply diffuser!!
Steve
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