Vaporproof boxes

[paulos1971]

I haven't done residential wiring in houses for a couple years. Someone told me that vaporproof boxes are required on exterior walls and on the last floor ceiling? I asked a electrician and he told me that is true per the 2011 code but only on the front and rear walls. I seem to get a different answer depending on who I ask. Does anyone know where they are required and also the section of the code book that its in?

 

[RLyons]

I think you mean airtight? We had a local AHJ require this for all outside walls and top floor ceiling boxes/cans but I'm curious as to the code reference as well.

 

[GoldDigger]

This would not be NEC, but it could be either building code or energy code.
It looks like the goal is to make it easier to prevent both moisture and air infiltration through the barrier membrane.


Tapatalk...

 

[jumper]

This would not be NEC, but it could be either building code or energy code.

Agree to both.

 

[Sierrasparky]

Not NEC but Energy code. Been that way in CA since last code. No one I ever see uses them. Arlington makes them.

 

[kwired]

I agree that it is not in the NEC and would be some other code.

From a practicality view, anymore most places around here are putting a coat of spray foam insulation on the exterior walls before filling the rest of the wall with loose fill insulation. Doesn't matter what the rating of any penetrations are, this stuff seals them from air flow.

 

[paulos1971]

Vaporproof boxes

I agree that it is not in the NEC and would be some other code.

From a practicality view, anymore most places around here are putting a coat of spray foam insulation on the exterior walls before filling the rest of the wall with loose fill insulation. Doesn't matter what the rating of any penetrations are, this stuff seals them from air flow.

I asked a city inspector and he told me it is in the 2011 NEC code. I don't have the 2011. Does anyone know where that woud be in the code book?

 

[kwired]

I asked a city inspector and he told me it is in the 2011 NEC code. I don't have the 2011. Does anyone know where that woud be in the code book?

Ask him for a section, I am almost willing to bet a high figure he can't find any such requirement, notice I said almost. This is building code type requirements, or even more likely energy code requirements if you have anybody enforcing such codes. Many places may have such codes passed as laws but may or may not have much for enforcement of it.

 

[bullheimer]

i believe it's up to the insulation contractors to spray foam in all the holes the cables come thru. so far i have not been required to put gaskets under any wall plates, but i have seen the insulation everywhere on outside walls like i said.