Molo
Member
Is there a fire hazard created when you put expanding foam around electric boxes? What, if anything, is safe when using the foam around a box?
Thanks for any replies
Thanks for any replies
Fire Hazard? Expanding Foam - Electric Boxes
- Thread starter Molo
- Start date
Speedy Petey
Licensed Electrical Contractor
Supposedly foam is fine around boxes. Just make sure all holes are sealed so the foam does not enter the boxes.
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In that case heat dissipation from the box due to I²R loss and bad wirenutting/connections depends on heat conduction through the copper and the cover plate being at room temp. I guess the NEC has already figured the boxes would be insulated with no air flow around them.
Speedy Petey
Licensed Electrical Contractor
I have never heard of "heat dissipation" around electrical enclosures being an issue.
A failed connection just need to be contained for safety.
I would say the NEC definitely has considered this assuming many boxes and enclosures are on exterior walls and ceilings.
A failed connection just need to be contained for safety.
I would say the NEC definitely has considered this assuming many boxes and enclosures are on exterior walls and ceilings.
I guess that means that enclosures have, or the air in them has, never gotten to 120 °C
"Wood slowly chars [at] 120°-150°"
but failed connections certainly have
"Electrical arcing [up to] to 3750°[C]
I guess air is pretty good thermal insulator.
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