proper support of luminaires in hung (suspended) ceiling?

kwired

Electron manager
Location
NE Nebraska
A lot of it has to do with the fire department, when they go in and start tearing down the ceilings they don't want the fixtures coming down too.
I can also understand that, but it would be a code other than NEC that makes this requirement. My comments have been primarily based on NEC unless otherwise stated, which is about the only code I ever have enforced on me. I have never attached a tie wire to a troffer that I can recall, NEC has never said I had to. If I did it was for some other practical reason and not because code made me do it.
 

iwire

Moderator
Staff member
Location
Massachusetts
I can also understand that, but it would be a code other than NEC that makes this requirement.
And maybe NEC 300.11, I am still on the fence about it

It makes no sense to me that a simple 4" square junction box used to supply a fixture needs to be independently supported but eliminate that junction box and use the fixture as the junction point and suddenly it does not need to be independently supported.

I have never attached a tie wire to a troffer that I can recall,
I have never not independently supported troughers in MA, CT, RI and we are not a sesimic area. I have always been told it is for the firemens safety .


NEC has never said I had to. If I did it was for some other practical reason and not because code made me do it.
Different AHJs may have different interpretations.
 

steve66

Senior Member
And maybe NEC 300.11, I am still on the fence about it
The handbook commentary pushed me off the fence. It starts like this;

"Wiring methods of any type and all luminaries are not allowed to be supported or secured to the support wires or T-bars of a fire rated ceiling assembly unless the assembly has been tested and listed for that use."

But I'm not going to try and look up the listing for a ceiling grid - maybe they are listed to have fixtures installed as part of a fire rated assembly. I think drop in ceilings only get a 15 min. rating, so a standard 2x4 with a metal shell may well be enough for a 15 min. rating.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
As an inspector it's my job to enforce all applicable codes. There's no where in the NEC that mentions switch and receptacle heights either, or smoke detectors, or lit exit signs, or emergency egress lighting, or a couple of other things I can't think of right now, but you still do them.
 

kwired

Electron manager
Location
NE Nebraska
How many people here have hung surface mounted luminaires from T bars using a T bar clip, or standoff type T bar hangers?

Did you also run tie wires to the luminaire? If you ran extra tie wires to the T bar only - the T bar is still 100% support of the luminaire.
 
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