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.

There is a study out there that came up over RX in foamed penetrations.(334.80)

http://gfretwell.com/electrical/NEMA%20Romex%20in%20foam%20study.pdf

Tesla, your concern is not completely unfounded.

NEMA, however, has issued a letter on the matter. After various tests, etc., it was determined that foam insulation posed no particular cause for concern. The jacket was NOT harmed by the foam chemicals, and there was NOT excessive heating on properly sized wires.

I agree that expanding foams are very combustible.

I would like to ad this link
http://www.safetyauthority.ca/files...%20Polyurethane%20Spray%20Form%20Ins.pdf

She asked for it, he did it. Had she asked to have all the plumbing vent stacks sealed with foam, he would have done that too.

If he refused, she would have found someone else to do it. The customer is always right.

It seems accessibility would also be an issue,which would be in direct NEC violation. You'd have to pry out an outlet and the wire for service and/or inspection. I don't like it.

As for peope letting drywall mud and paint into panels, almost every interior panel I've opened that was installed prior to 1980 has an absurd amount of crap in it. Apparently they had not heard of masking off anything that the buyer would not normally see before purchasing the house. This usually includes te busses as well!

I imagine he also insulated all of the switch boxes as well?
The guy probably thought the orange fire stop expanding spray foam that they sell at HD and Lowe's was just perfect for the task at hand. I'd hate to be the guy who has to clean out all those boxes... that stuff dries really hard, almost like structural spray foam... and what about dimmer switches, etc., when they start overheating.

You never know these days though. This insulation guy might end up being considered a pioneer and nominated for the next Nobel Peace Prize.

I am sure the foam issue is not an issue in the walls. the OP was foam in the in the box itself which is not mentioned in the NEMA study.

I've seen instructions on the cans of spray foam saying not to use it inside electrical boxes. So it's definitely not "listed for the purpose"...

arent they supposed to label the cans "fill around electrical boxes and penetrations"?

Accessibility. If this foam gets hard, the conductors are no longer accessible.

I know this is a 2 month old post but thought I'd add one more point: Why does the insulation contractor care? He doesn't fail electrical insp. NEC and NEMA violations are irrevelent to him as long as he can back up/substantiate his answer that it's "code compliant"; after all, he just did what the customer wanted.
(I've had this prob on a smaller scale and I don't agree with him, just playing devil's advocate)

I’m just wondering what code in particular the guy was referring to though... when he told the homeowner that it was in compliance.

Maybe it's the super secret handyman insulation code

I think it was the "Code of the Handymen".

It goes like this:
"If I say that it doesn't meet Code, they won't pay me to do it; when they find someone who tells them what they want to hear, they'll pay HIM instead of me".