Foam Insulation Derating

[360Youth]

I was checking in on a job today and started noticing some of the spray insulation all over a lot of the wire. i am sure this has been covered here somewhere in the forum (I did a search and read some of the results, but none pertained to what I was looking for) and I am sure it would not be in existence if there were any everyday concerns, but I was hoping for some feedback/point me in the right direction literature for things to look out for in these circumstances. I guess just getting a good visual of the cables encased in the foam the way they were seemed a little odd. I have done hundreds of homes and I suppose that cables in standard wall insulation is subject to heat build up, but everybody has a first time for everything and I just don't know that I have dealt with on one of our jobs this spray foam. Anyway, have at it. Thanks.

 

[Dennis Alwon]

Thom there is nothing that I know about this stuff that would make it an issue. I think wires in close proximity but not bundled could be more of an issue but code is silent on it.

The issues I have had were when they install that stuff in a ceiling over a recessed can. I have had then encase the can so that replacement and access to the jb is not possible without damage to the ceiling. I will not allow recessed cans in a ceiling where this foam is used. That is Dennis' rule although I don't see how it is compliant with no access to the jb.

I figure there will be issues with this in the next 10-20 years and someone will scream about it.

 

[bobserrano]

I think the issue is when 2 or more NM cables bundled through holes in wood framing and insulated or when 2 or more NM cables are bundled and in contact insulated is when derating kicks in. See the last 2 paragraphs in 334.80