Weather-proofing Outlets

[kweiss]

Came across a nice little home today that had an enthusiastic do it yourselfer living in it apparently. Did most things okay, if not pretty.

One thing I am not sure about was that he had used the spray expandable foam stuff on most of the exterior wall outlets inside. From what I could see it looked like he sprayed it on the cover then installed it. Since there was seepage around the cover at the outlets on some.

So my question is - Is this acceptable? Is there a fire hazard with this foam? Obviously I cannot tell exactly what kind of foam he used. Tried to take a couple of the covers off and could not easily get them to come off, didn't push far enough to cut them off. I have always told people to use the little foam gasket things.

[rromoser]

If the outlet box is filled with foam there would be an increased risk of fire. Electrical boxes require a minimum amount of cubic inch space for conductors to cool. (#14 requires 2 cu. in. #12 2.25 cu. in.) Removing the foam or replacing the receptacles seems like it would be quite a project.

[rmaday]

Originally Posted by rromoser

If the outlet box is filled with foam there would be an increased risk of fire. Electrical boxes require a minimum amount of cubic inch space for conductors to cool. (#14 requires 2 cu. in. #12 2.25 cu. in.) Removing the foam or replacing the receptacles seems like it would be quite a project.

Agreed, conductors are not made to be encapsulated in foam. Also, if a receptacle went bad, he'd have a hell of a time putting in a new one.

Certainly something your client should know.

Got pics?

[Mark E. Northrup]

The foam is a bad idea as has already been stated. I have seen windows crack and door bind from the oil based product being used. Not good the latex are better but should not be used in electrical areas.

[kweiss]

I could not get the covers off, as the foam acts like a good glue. I tried but came close to breaking the cover. Going to take some combination of cutting and prying to get the covers off, which I was not going to do with the power on. So i am not positive how filled the boxes are. But the fact that there was excess squeeze out between the cover and the outlet holes makes me nervous.

Going to refer it over to an electrician.

[kweiss]

Also did a quick google search. Appears taht Great Stuff's maker Dow chemical says that it is acceptable to use behind the boxes in the wall but not inside the box. So our instincts were corrrect.