Mounting T5 lights to metal ceiling

[c6matt]

I did a search and came up empty and I am sure it has been done. I just ordered 9 8' T5 fixtures

http://www.contractorlighting.com/8...scent-double-channel-strip-120277-p-1475.html

can I screw them directly to the metal ceiling?
Should I put up the ceiling and then worry about cutting the holes for electrical boxes/wiring?
What is the proper way to wire these, do you run the romex right into the fixture? (no box required?)

Any other installation "gotca's" to watch out for?

 

[JohnX14]

I checked out your build thread. I would screw through the metal ceiling and into the trusses. You can connect the romex right to the fixture with a connector, but make sure to drill a large enough hole through the skin so that it doesn't cut the romex.

 

[c6matt]

prefect, thats what I was hoping would work. Popping some screws into the trusses and a 1" hole in the metal will make that job cake!

 

[JohnX14]

I'd probably do more like a 1.5" hole saw hole through metal ceiling to allow room for the connector behind the fixture.

 

[C96]

I'd probably do more like a 1.5" hole saw hole through metal ceiling to allow room for the connector behind the fixture.

^^^^ This ^^^^

 

[c6matt]

^^^^ This ^^^^

perfect, now I just need to figure out how I want to Wire them.. (how to break them up on the switches) prob do 3 rows front to back of the garage, IE all 3 rearmost on 1 switch, ect

 

[JohnX14]

Don't overthink it. Put them on 3 switches, but put all the switches in the same location....very likely you will always put all of them on so keep them together. You don't want to be walking to several locations every time you use the garage.

 

[c6matt]

yea, I was planning on a bank of 3 at the man door and another 3 in between the big doors set up in a 3 way config..

 

[c6matt]

and thanks you guys for the input! I appreciate it!

 

[Highbeam]

I just hate putting all those 1.5" holes in the ceiling which would let all the heat out. It's like leaving a door open. Won't insulation fall down? and if you center the holes over the knockout be sure that you choose a knockout in the fixture that would prevent the big ceiling hole from being visible from below.

 

[JohnX14]

I just hate putting all those 1.5" holes in the ceiling which would let all the heat out. It's like leaving a door open. Won't insulation fall down? and if you center the holes over the knockout be sure that you choose a knockout in the fixture that would prevent the big ceiling hole from being visible from below.

He could certainly drill a hole to fit a 1/2" ****** tight and put a connector on the end of the ******. But he can also insulate the penetration.

 

[pattenp]

My opinion is where NM passes through the metal ceiling the hole would require an insulation bushing or grommet just the same as when NM passes through metal structure members.

 

[JohnX14]

My opinion is where NM passes through the metal ceiling the hole would require an insulation bushing or grommet just the same as when NM passes through metal structure members.

I think that is not necessary or required if either a traditional metal romex connector or a T&B 3201 style connector is used. Possibly an argument to be made if a black button type of connector is used. May be a good idea, regardless. With the romex secured to the connector which extends above the plane of the ceiling I don't see the analogy to a metal stud.

 

[pattenp]

I agree with what you are saying. I was thinking that the NM was passing through the metal ceiling to a fixture that was not flush/surface mounted and the NM would be exposed to the metal cut edges.

I think that is not necessary or required if either a traditional metal romex connector or a T&B 3201 style connector is used. Possibly an argument to be made if a black button type of connector is used. May be a good idea, regardless. With the romex secured to the connector which extends above the plane of the ceiling I don't see the analogy to a metal stud.

 

[Charles (in GA)]

It depends on if the lights are mounted on top of the metal's ribs, or running with the ribs and mounted in the valleys. If running across the ribs most of the light fixture will be spaced some distance from the metal, contacting only on the top of the ribs. In that case, the romex would need protection where it passes thru the ceiling sheetmetal, plus the metal or plastic connector in the fixture. If the light is mounted tight with the metal, in the valleys, then a hole large enough for the connector to protrude thru would be needed, and no additional protection would be necessary.

Charles

 

[Aceman]

It depends on if the lights are mounted on top of the metal's ribs, or running with the ribs and mounted in the valleys. If running across the ribs most of the light fixture will be spaced some distance from the metal, contacting only on the top of the ribs. In that case, the romex would need protection where it passes thru the ceiling sheetmetal, plus the metal or plastic connector in the fixture. If the light is mounted tight with the metal, in the valleys, then a hole large enough for the connector to protrude thru would be needed, and no additional protection would be necessary.

Charles

Thank you for typing this, I was about to post the same thing.

 

[Zippercat]

Could (should?) the holes be sealed with firestop caulk?

 

[Zippercat]

Could (should?) the holes be sealed with firestop caulk?

 

[Charles (in GA)]

Could (should?) the holes be sealed with firestop caulk?

Probably not a bad idea. There is spray foam that is firestop, and also caulk that is firestop rated, so it is readily available now, and not crazy expensive.

Charles