Question on Shop Lighting for Electricians

Hey Fellas:

I have 2 banks or rows of florescent lights in my shop on the same breaker. These are (2)-tube 4 ft. fixtures. I constantly have a problem where on one bank only the lights will go out (stop working) over a period of time from 5 minutes to possiblly an hour. They don't go out at once, but individually on their own. I have tried different fixtures (from other manufacturers) with the same end result. This seems (to me) to indicate a circuit issue although the circuit was checked out when my shop was built. The inspector just used one of those circuit "checkers" that plugs into the receptacles.

Any ideas, suggestions and recommendations toward correcting this problem would be much appreciated. (I am on-line each day but not too long. So, my replies may be a little slow but I'll do my best since I'm posting this.)

- EM

 

need to know how many fixtures you have on that one circuit , how many amp breaker the circuit is and how many watts each fixture pulls ? how long have they been installed ? sounds like a cheap ballast problem to me ! ballast getting hot and going out untill cooling off ! did you buy the fixtures from an electrical warehouse or are they menards specials ?

 

Could be a lot of things, i bet that you are getting fixtures from home depot or lowes and they are chinese junk for sure. What i'd suggest is to start replacing those ballasts with electronic, do one at a time. You won't regret it.

 

OK both banks are wired together and on the same breaker. Now you said it happens on one bank only... if it only happens on one bank and not the other, it is a wiring problem, perhaps a bad splice (high resistance splice) etc. Check the wiring.

 

Since you indicated you already have replaced fixtures and the breaker isn't blowing then you are down to the wiring. Sounds like it is loose or corroded connection to me. Could possibly also be a broken wire that is making contact sometimes, but not always. You will need to just start checking in j-boxes along the line and take apart connections and clean and retighten them until you hit the one that is causing the trouble.

It may or may not be obvious which one it is. Sometimes it might cause blackening and will be visible when you see it. But if it isn't too loose and it hasn't been too long, it might not really be that obvious.

Just get as many as you can and hope you hit the right one. If not, try others until you do.

If you know how the wires are run, you can probably already narrow it down to 1-2 likely connections. I would start at the fixtures that are working fine. My guess is that it is the wire going from there to the bad fixtures.

 

Thanks Much Coupe Guy and Stude Trucks. You guys are at the point I am but you have provided some specific avenues for me to take. The splice and loose connection sound most likely. Fortunately I do know how the wires are run because I pulled everything myself. I'll follow your suggestions and see where this leads. Today is too hot out there so it will need to wait.

Thanks much,

- EM

 

ballasr wiring or bulb/ Ive had new ho work for about 3 months and then went out .That was a bad ballast.........Bad tubes will fool you also.........Also what size wire 12/2 with ground or other ,And are they regular flourescents or Ho

 

Check for loose nuetrals in your branch wiring, at the switch box and any j boxes that may tie your switch leg to the lights themselves. When using a tic tracer it will show power on your hot conductor, but you cant tell if the nuetral is not making connection. If that doesnt fix the problem then try replacing ballasts. Good luck

 

Look at you ballasts and see if they are "thermally protected', if so they are just getting too hot . You can drill cooling holes in the fixture to get the heat out . Look at the lamps and make sure that they match the ballasts. A 40 watt lamp will not do well behind a 32 watt ballast. If your ballast calls for a "T-8' the lamps will be 1 inch diameter , "T-12" wil be 1 1/4 diameter. Hopes this helps

 

More than likely, ballasts. Ballast heats-up and "breaks" inside. Turn your lights ON. As soon as one goes out, CAREFULLY feel the ballast. If it's too hot to touch, you've found your problem. Bad bulbs usually won't come on to begin with. DD

 

Had the same problem with mine, more when it was hot out. Changed the ballast to solid state electronics, and problem solved!! Instant on, no warmup, works great!!