spray foam INSIDE electrical boxes

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donniet

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This is a very bad practice, but need some reference material here. Does anyone have any code reference as to why you should not use spray foam insulation inside boxes to seal them? I've been discussing this with a DIYer and he seems to think it's a best practice to fill up most of the box with foam after he has all of his wire run.
 
Besides closing off access for future runs, that spray foam will decrease the volume in the box. And that's a no-no by NEC 314.16:
In no case shall the volume of the box, as calculated in 314.16(A), be less than the fill calculation as calculated in 314.16(B).
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cowboyjwc said:
I would say that box fill would be a concern and possibly 110.11.
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I was also thinking 110.11, but then people use spray foam to seal around nm cable thru bored holes.
I do not think it is a good idea to spray it inside the boxes though.
 
C3PO said:
I was also thinking 110.11, but then people use spray foam to seal around nm cable thru bored holes.
I do not think it is a good idea to spray it inside the boxes though.
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That was kind of my thought too, that's why I said possibly.;)
 
Seems like a vilation of the spirit of 370-20, if not the letter. I can't see how installing combustible material inside an outlet box is OK.
 
donniet said:
This is a very bad practice, but need some reference material here. Does anyone have any code reference as to why you should not use spray foam insulation inside boxes to seal them? I've been discussing this with a DIYer and he seems to think it's a best practice to fill up most of the box with foam after he has all of his wire run.
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OK, why? Why are they feeling this need, is the cold coming in or going out? Can you hear the next room ? Are they scared that this is going to
spontaneously burst ?

One can buy Fire pads for the outside of an electrical box, I've never used fire pads inside a device box, but I have seem them installed and they were installed before the sheet rock went in, in both cases.
The inside box work was usually 6x6 or 8x8 flush mounts. The outside pad to device boxes were done due to fire rated-seperation walls.

You better watch out for the DIY, a man and the castle, their never wrong, just wait till the bugs move into the foam and the home inspector fines it...

Oh wait you wanted a code refernce I don't have one. Frankly I don't want to even research this one...

I will say, I feel like the inside of a electrical box is my property just like the Federal goverments owns the insides of every mail box across this great land, you better watch what you put in there, or take out of there.
 
C) Integrity of Electrical Equipment and Connections Internal parts of electrical equipment, including busbars, wiring terminals, insulators, and other surfaces, shall not be damaged or contaminated by foreign materials such as paint, plaster, cleaners, abrasives, or corrosive residues. There shall be no damaged parts that may adversely affect safe operation or mechanical strength of the equipment such as parts that are broken; bent; cut; or deteriorated by corrosion, chemical action, or overheating.
 
" ? "

" ? "

It most be 2005's ( You made me look )

2008 there a ? between 110.12(A) and 110.12(b)

? means = Where one or more complete paragraphs have been deleted, the deletion is indicated by a (?) PAGE 70-1.

There is no 110.12(C) in 2008.

in 110.12(B) Integrity of Electrical Equipment and Connections
Internal parts of elec. equip., including, busbars,wiring terminals, insulators, and othe surfaces, shall not be damaged or contaminated by foriegn materials...
 
I think the question of "WHY" is just as good as the 110.12(b) or (c)
Why would someone think this is a good idea. Oh wait a second DIYer, forget the Why question. Just start figuring out how much to charge to redo his work when you get the call. :smile:
 
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