I am finishing a lighting job and am having trouble with blowing ballast fuses. Each 20 amp 277v circuit has five 6 lamp T-5's. Each fixture has 2 3-lamp ballasts. Each ballast has a 3 amp fuse. There are 84 fixtures in the building. When we first turned them on we had 6 fixtures out, either 1 or both fuses in each. Over the past few days as the lights are being switched on and off we have lost another 18 fixtures. We have good voltage through out, When we bypass the fuse the fixtures pull the correct amps. Any quick and or easy ideas would be greatly appreciated. Thanks for the forum!
Ballast fuses
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buddhakii
Senior Member
- Location
- Littleton, CO
Is there anything in the install instructions that states you need to burn them in for 24 hrs.?
yankj
Senior Member
- Location
- Carrollton, Texas
Call factory tech support
I had to troubleshoot the same deal with outdoor lighting once before. Found the fuse were not holding the starting current. These were in the 2-3 amp range with 12 awg tap conductors up the pole. I increased the rating and and still protected the conductors. I don't see what protecting the ballast does. It's the conductors we're protecting.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
It's not easy to blow both fuses supplying a single load. Could there be a mis-wiring of the sockets? Pinched wires contacting metal?
masterinbama
Senior Member
- Location
- Huntsville Alabama
I know the OP was for indoor t-5's. As far as fusing individual ballasts It sure comes in handy when troubleshooting a parking lot full of 400 watt MH fixtures with one ballast dead shorting the 480volts? Unless it smokes the lens it's like trying to find a needle in a haystack.
Cow
Senior Member
- Location
- Eastern Oregon
- Occupation
- Electrician
It's keeping a shorted ballast from wiping the whole circuit out. You'll appreciate that little fuse next time you have to troubleshoot those lights and it doesn't take you all day to find the bad fixture.
Ballost Fuses
Ballost Fuses
Try putting an amprobe on the wire feeding the 3 amp fuse. Turn on the fixture and watch the amps on the digital readout in the first 10 seconds. I think you will find the amps go real high at first and then settle down. Try a slow blow fuse. You also need to call the company and ask if you can use one of higher amp rating.
Ballost Fuses
Try putting an amprobe on the wire feeding the 3 amp fuse. Turn on the fixture and watch the amps on the digital readout in the first 10 seconds. I think you will find the amps go real high at first and then settle down. Try a slow blow fuse. You also need to call the company and ask if you can use one of higher amp rating.
cadpoint
Senior Member
- Location
- Durham, NC
- Occupation
- Electrician - but not by NC Law.
First, I've never installed a large array of lights indoors in this manner,
Frankly I can't recall ever have fuses in any indoors lights, out doors, yes.
Now my question is here does a fuse act as a disconnect or is the new orange disconnect still required in front of the fuse ?
Is this it not a design choice by the engineer or an offered suggestion from the lighting manufacture. Surely they'd know their spec's if an installer decided to insert the fuse. Or is this just SOP for "high bay" lamping etc. Fused period !?
I believe one of those incorrect terms sneaked into this thread, "Slow Burning Fuses", no it's called something else, LOL.
Well maybe no, the manufacture is allowed to exactly name the other fuses except what required by UL/CSA 248, interesting.
I thought there was three or is it four standard types of fuses, but no theres seven, there's some good information at this web site, (no support is implied by list this manufacture!)
By the way Cow! I enjoy the cheese! :grin: (no support implied by that statement either), but it darn tasty!!!
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