LED "High Bay" lighting

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tadavidson

tadavidson

Senior Member
Location
Georgia
Occupation
Electrical Contractor
I am mounting 124 High bay, LED, fixtures at operating voltage of 277 in a Metal frame building. The girders are 24-27 inches wide from outer wall to center. The owner wants the lights hung from the metal rafters not to fall below girder level. Mounting of the fixture is eye bolt and stainless steel cable, The fixture came with a fixture wire approximately 12" in length, not enough to reach anything for solid mount. There is an existing conduit grid for lighting in this ceiling putting the connection boxes from 5' to 15' in distance from each new fixture.
The original plan before the fixtures arrived was to run MC from tap box to fixture. I have a couple of ideas but would appreciate the wealth of experience here.
 
57 expert, Master Electricians, Engineers, have stopped by but not one comment. What gives?
 
Because you, like everyone else, won't give us a model number of what you're working with.
I'm tired of asking. I'm getting old(er).
 
ptonsparky said:
I can't figured out what your layout is, I'm sure you know but it's clear as mud to me.
Why don't you want to go with with the original plan?
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The fixture won't accept any connections directly. The 12" fixture whip tap is inaccessible.
 
Sorry, I don't have a number my question was more to a method of connecting a 12 inch SO cord whip to the flex in mid air; lol'
mgookin said:
Because you, like everyone else, won't give us a model number of what you're working with.
I'm tired of asking. I'm getting old(er).
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mgookin said:
Thanks for the clarification. :thumbsup:
And sorry for being grumpy last night.
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No apologies necessary. You made a valid point. I appreciate you even bothering to comment. I ended up mounting a "handy box" to the top side of the fixture and cable clamped thewhip on one end and MC into the other. If I can remember how to load pic on here I'll leave one tomorrow.
 
Interesting post. I'm working on the same thing. We may put it off a couple of years because the average LED efficiency is about 100 Lumens per Watt, same as the GE high pressure vapor lamps we're now using. Best I've found is like 165 L/W but price goes way up.

Question I have is, NEC says the luminares must be directly below the outlet when using a straight blade outlet. (or is twist lock now required?) What do they define as "directly below?"
 
david.mullins said:
Interesting post. I'm working on the same thing. We may put it off a couple of years because the average LED efficiency is about 100 Lumens per Watt, same as the GE high pressure vapor lamps we're now using. Best I've found is like 165 L/W but price goes way up.

Question I have is, NEC says the luminares must be directly below the outlet when using a straight blade outlet. (or is twist lock now required?) What do they define as "directly below?"
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If your fixture is 2'x4' I would say you need to be within that area, straight up from it. A 6" diameter fixture would require the same.
 
ptonsparky said:
If your fixture is 2'x4' I would say you need to be within that area, straight up from it. A 6" diameter fixture would require the same.
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Some of the existing ones are over a foot away from the plug, down a foot and over a foot. So, if I put two fixtures end to end, then I could maybe have a foot gap between them and the end of each, where the cord comes out of the fixture, is 6" horizontal from the outlet?
 
david.mullins said:
Some of the existing ones are over a foot away from the plug, down a foot and over a foot. So, if I put two fixtures end to end, then I could maybe have a foot gap between them and the end of each, where the cord comes out of the fixture, is 6" horizontal from the outlet?
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This is up to your local AHJ. I personally would not have problems with it, but that counts for naught. I can say that it will look good from here.
 
ptonsparky said:
This is up to your local AHJ. I personally would not have problems with it, but that counts for naught. I can say that it will look good from here.
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Our fixtures are circular and about 18 inches across. We mounted a 4x1.5 Utility box to the top side (had two threaded holes) and ran MC from the nearest j box that contained the old lighting circuit to that box.
I trust that was compliant. Anyone know of opposing code?
 
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