2005 nec 334.12(A)(2)

[knoppdude]

Does anyone know the reason behind the change in the 2005 NEC that prohibits using NM cable above drop type ceilings in non residential occupancies? I am wiring a used trailer for use as offices, and the existing wiring is romex above the ceiling. I was told to run feeders overhead using NM cable, but as I read the NEC, it has to be protected by some type of raceway.

 

[Nium]

Smoke

Smoke

I believe it's to prevent the release of toxic smoke (from the NM jacket), in case of a fire, from being drawn in by the air handling system. Also the same reason white zip ties can't be used above a drop ceiling in commercial applications. That's my guess at any rate.

 

[Volta]

I would guess it is more about the rough environment above the ceilings with sharp metal, support wires, and just how careful tradespersons are . . . much less activity in residential ceiling spaces.

If it was simply about air handling spaces it could be allowed in non-air handling areas.

 

[don_resqcapt19]

There is no real or technical reasoning. It was part of the horse trading that was used to remove the 3 story limitation on the use of NM.

 

[LarryFine]

Also the same reason white zip ties can't be used above a drop ceiling in commercial applications.

Really? Uh-oh. I hope that's for plenum ceilings only.

 

[mcclary's electrical]

Really? Uh-oh. I hope that's for plenum ceilings only.

that one was news to me also.

 

[kbsparky]

Purely political. Horse trading, as someone else put it.

The Code is moving away from being written purely for safety's sake, and becoming more politicized by being laden with lobbyists from various industries and manufacturers.

Even the CMPs have industry "reps" on them, looking out for their own special interests.

 

[shepelec]

Yup, I say it was the companies that make MC cables that felt they needed to sell more cable. Kind of like some of the other rules that get implemented.:roll:

Can't use white tye wraps in non-plenum?? Thats a new one to me also.

 

[Nium]

Really? Uh-oh. I hope that's for plenum ceilings only.

yes, plenum :roll:

 

[electricdoug]

Is there any such limitation on running phone/data cable above a ceiling?

 

[acrwc10]

I would guess it is more about the rough environment above the ceilings with sharp metal, support wires, and just how careful tradespersons are . . . much less activity in residential ceiling spaces..

maybe it is the opposite, that "less careful tradespersons" are more active in commercial spaces. :grin:

 

[mcclary's electrical]

maybe it is the opposite, that "less careful tradespersons" are more active in commercial spaces. :grin:

The way I read his statement, that's what he meant. He just said it humorly

 

[Volta]

The way I read his statement, that's what he meant. He just said it humorly

:grin:

_____________

 

[hurk27]

Purely political. Horse trading, as someone else put it.

The Code is moving away from being written purely for safety's sake, and becoming more politicized by being laden with lobbyists from various industries and manufacturers.

Even the CMPs have industry "reps" on them, looking out for their own special interests.

Oh no not another congress