Wiring up fluorescent fixtures

[TheGorf]

Howdy all, i'm excited to find those forum. I'm currently building a 24x36 shop and I have about 12 foot ceilings. I've decided to go with 8' fixtures with 4 x T5HO bulbs in each fixture. I will have three runs of 3 fixtures. Testing with two fixtures seems that it should produce good light once the dry wall is all up.

Anyway, there is a 3/4" knockout on the back of them to run my wiring down through. So my question is, how do I correctly wire this (I'm in WA, USA)? Is it ok to run to a junction box on top of the bottom 2x4 of the truss then come out of that box about 12" with romax down through the ceiling drywall and into the knockout (with a romax clamp)? Or am I totally wrong here?

 

[vartz04]

But a box extender on your J box and then use a short piece of conduit or a connector between the box and the fixture. Romex can't be exposed. You could use metal flex conduit as well.

 

[pattenp]

There is more than one way to wire them. If the fixtures are surface mounted you can bring the romex through a hole large enough in the drywall for the romex clamp to fit in and bring the romex straight into the back of the fixture. I assume the fixtures you have can be used to junction wire to run back up and on to another fixture.

 

[TheGorf]

There is more than one way to wire them. If the fixtures are surface mounted you can bring the romex through a hole large enough in the drywall for the romex clamp to fit in and bring the romex straight into the back of the fixture. I assume the fixtures you have can be used to junction wire to run back up and on to another fixture.

Yeah they are surface mount and the punch out on the fixture is on the back which is flush against the drywall. Sorry if that wasn't clear. So that is why I was asking if I can just punch a hole in the drywall that the romax clamp will fit through. That way it is never exposed to the outside world.

 

[pattenp]

But a box extender on your J box and then use a short piece of conduit or a connector between the box and the fixture. Romex can't be exposed. You could use metal flex conduit as well.

NM-b (Romex) in 1 and 2 family dwellings, their attached or detached garages, can be exposed if installed where not subject to damage. NEC 334.10, 334.15

 

[vartz04]

In a garage it would be subject to damage if exposed.

 

[Stuart in MN]

If the fixtures are surfaced mounted against the ceiling, and the wiring will be above that ceiling, you don't need junction boxes - just run the Romex directly into the fixture through the hole, make connections and then run the Romex back out through the hole and on to the next fixture. Use a clamp on the hole, of course, and secure the wiring in between fixtures to the ceiling joist or truss with conduit staples. Also, make sure the fixtures are rated for surface mount use, not all of them are.

 

[usa#1]

I spaced my fluorescent fixtures off the ceiling using short pieces of 1-1/2" or 2" pipe and ran the wiring from the attic space through the drywall inside the pipe. I used 3 or 4 pieces of pipe for each 8ft fixture.

 

[pattenp]

In a garage it would be subject to damage if exposed.

Not in every case. I've seen plenty of unfinished garages with Romex stapled to the side face of studs serving outlets. It's very common. The "subject to damage" clause is very subjective.