I have a customer (recent widow) who lives in a large home on the lake. In the winter the wind pressure is so great she can't get her kitchen temp over 50. She recently had a spray foam contractor foam her attic. While there, she asked him if they could fill the electrical boxes. He said he could and he did! Three floors worth. When I found out and expressed my opposition and displeasure about it she got back in touch with them. They told her the foam is non flammable and code compliant.Although I intuitively know this is illegal, I cant find any code language to back me up. Any thoughts? My next call is to my state inspector, but I thought I would start here first.
Thanks,
Dave.

Is it listed for the application?

I would include foam in that category

Is it listed for the application?


I haven't seen any paper work yet. foam guy said he will bring it to her but I still can't believe filling an electrical box full of spray foam is acceptable.

If you fill the box with foam, what does that do to the device and wiring fill calculations? Won't the wiring devices be unable to get rid of their waste heat?
I'm sure that UL doesn't test these things wrapped up like a pig in a blanket.

I would get the MSDS from the installer and a statement in writing that this material is non-flammable.
If it is foam like I am imagining, it ISN'T non-flammable at all.
Having this sort of thing in such close proximity to a possible bad connection of what-not, is just asking for trouble.
There are better ways to achieve a good seal in boxes, you just need to use a bit of grey-matter.

You also have to ask about the quality of the house construction, if the building cannot be heated to any great degree.
I'd be talking to the Contractor about that, it is HIS problem.

I think it is a lot simpler than that. We regularly tag panels and boxes that get too much drywall mud in them on a 110.12(B) and require that they get cleaned out.
(don't we?).
That is clearly not a flammability issue it is "contamination" by a "foreign material".
We can think of a number of reasons why the foam is bad but I wouldn't over think this.

Who in their right mind would leave a panel open to plaster and paint damage, in a new install?
There are things called masking tape and paper (or plastic film).
There is no reason that these materials should be finding their way into electrical enclosures, no matter how small.

Cardboard being removed by others, stupid painters who are too lazy to mask it off, the list goes on and on.....

Romex foamed in this manner must loose its ability to dump heat.

This is an issue worthy of an NEC revision/ NTL evaluation.

And as for the box foam-fill...

Of course it's a violation. The urethane foam is combustible.