ECN Forum Forums General Topics of the Trade General Discussion Area NMC in contact with spray foam insulation?

Greg:
Insulation is usually not installed until after 'rough' electrical approval, followed by a framing approval. As the ECs are long gone, after completion of rough wiring, who is to 'see' the insulation job. Spray foam in this discussion.

The Ecs usually are not back on site until trim out time. The inspectors are not back till final.

I understand the inspection issue but if you know they are spraying foam, you will see the violation coming at the rough. Since the holes have to be draft stopped, those will be obvious. I suppose the question is what would constitute "spacing" in these penetrations? If you just pushed the RX apart and jammed something in between them,(Romex jacket, stick of wood or whatever)is that spacing?
Certainly if the EC had collected some pieces of duct board, left over from the HVAC guys and jammed some in between RX in the holes, he has met the intent of the code assuming there is any wiggle room at all.
You should be drilling more holes anyway if you have that much RX in one hole. I guess the issue comes up most right above the panel where you have a whole bunch of cables in the same spot. That has always been troubling, one way or the other. Again, as long as each cable has some space around it when they pump in the foam, no problem as I see it. It is only when they are "installed without maintaining spacing" that 334.80 comes in.

Gentlemen,

338.40 applies to over 24"

yes/no....

~S~

Also, 312.5(C)EX. is commonly utilized , especially in all those prefabs we pass by everyday

Juxtapose to 338.40 please.....if it isolated from foam via pipe ...etc....

~S~

338.40?

I don't have that one

334.80, pardon my dyslexia Greg....:( ~S~

334.80 does not say 24" anywhere. The only reference to 310.15 is to the table and the exception that does not apply.

Scenario then....

312.5(C) EX , 2---2" sch 40 pipes from basement panel , run up to but not penetrating ceiling, meets all of provisions a-g

2 larger holes are drilled , about a dozen rx conductors each hole, down into pipes/panel.

These bored holes go thru 2x4 plate & decking , for a total of 4"

The ONLY place where they can be seen as 'bundled' is withing this 4" passage

This is the foamed

What code is violated please?

~S~

~s~
Based on what you stated, IMHO.....no issues

Unfortunately 334.80 does not specify a distance. If they are bundled in a bored hole in wood and foamed in, that is a violation.

Do I agree? No ... but that is the way they wrote it and I have been in a number of inspector meetings who agree it is what they say, as stupid as it sounds. I suppose you can 90.4 it.
I have not looked at the proposals since but it would be interesting to see what NFPA says.