Home>Discussions>ELECTRICAL & LIGHTING>Firestop For Plastic Electrical Boxes
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dcalabro
Firestop For Plastic Electrical Boxes

Are there any firestop requirements with regard to those blue plastic electrical boxes? I see them used a lot, myself included, and the knockouts that you run wire through leave me unsettled. My guess is that a few sparks could easily jump out of the box and catch on framing. Something i'm missing here?

Gizmo
Re: Firestop For Plastic Electrical Boxes
canuk
Re: Firestop For Plastic Electrical Boxes
dcalabro wrote:

Are there any firestop requirements with regard to those blue plastic electrical boxes? I see them used a lot, myself included, and the knockouts that you run wire through leave me unsettled. My guess is that a few sparks could easily jump out of the box and catch on framing. Something i'm missing here?

For standard use there's no need for any extra firestop .
Unless the boxes you are using come from some black market source then they should meet all compliance ratings.

Besides, have you looked at a metal box --- they're not exactly hermetically sealed either.

dcalabro
Re: Firestop For Plastic Electrical Boxes
canuk wrote:

For standard use there's no need for any extra firestop .
Unless the boxes you are using come from some black market source then they should meet all compliance ratings.

Besides, have you looked at a metal box --- they're not exactly hermetically sealed either.

True but I guess I just assumed knocking a hole in a plastic box is worse than a knockout on a metal box to which you can use a cable clamp to seal that penetration. While neither solution is would be a perfect firestop, I assumed there was something else to be done.

Thanks for the link to the putty.

canuk
Re: Firestop For Plastic Electrical Boxes
dcalabro wrote:

True but I guess I just assumed knocking a hole in a plastic box is worse than a knockout on a metal box to which you can use a cable clamp to seal that penetration. While neither solution is would be a perfect firestop, I assumed there was something else to be done.

Thanks for the link to the putty.

One main reason for the box is to keep device connections and splices from direct contact of combustible materials --- unlike open air splices which when buried in a wall are more likely to be in direct contact with combustibles.

Fencepost
Re: Firestop For Plastic Electrical Boxes

I've only seen fire caulking required where the box is installed in a fire-rated wall, such as the wall between the garage and house. I think plastic boxes may be permitted when properly caulked.

Carlon (a maker of plastic electrical boxes and other devices) has an interesting white paper regarding the fire safety of PVC electrical conduit & raceways. They assert that a plastic device may provide greater protection than a metal one.

http://www.carlonsales.com/techinfo/codesstandards/CS-Fire_PVC_Building_Codes.pdf

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