Electrical Boxes/Rated Wall

[jmc]

I've heard about the requirement for elec boxes to either be rated and or putty packed when placed in a rated wall. % or number of boxes in a stud wall cavity etc. Can someone direct me to the appropriate code sections?

2011 NEC/2012 IBC

Thank you.

 

[fatboy]

2012 IBC Section 714 Penetrations, more specifically to boxes in walls, 714.3.2

 

[BSSTG]

Greetings

If I remember right you don't need putty packs for penetrations of 2 hour walls with standard metal boxes. You have to see what the box is rated for. Even the plastic boxes are rated. I've never quite understood that since all of the elect boxes have nail holes, cable cutouts and the like. Go figure.

BSSTG

 

[BSSTG]

Greetings,

I had a few spare minutes and dropped by a new electric supply house to see if I was remembering all of this correctly. Metal and plastic device boxes are not required to have the putty packs as they are rated and listed for 2 hours (at least on the ones I investigated). The only time the packs might be required is if holes on opposing sides of the wall are within 24" and there is no batt insulation. That's what I read in listing information in the catalogs.

BSSTG

 

[ICE]

I have seen putty pads required for controlling sound transmission. One would think that the pads are easy to install but if they aren't pressed on really well they tend to fall off.

 

[north star]

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FWIW, ...here are some pics. of some fire rated products.





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[steveray]

All good info......first you need to know the rating of the wall, what type of assembly it might be (firewall, fire barrier, fire partition, vert exit enclosure) and follow those code sections (Ch. 7) to allowable penetrations and protection thereof...

 

[Span]

Agree with BSSTG, 714. be able to use other listed materials and methods for membrane penetration only, not through. 718.2.1.1 allow batts or blankets of mineral wool or fiber.

718.3.1 allow glass fiber for draftstop. As steveray says you need to know what wall first.

https://ibcode.com/Code_Questions.html also have good code info.

 

[Builder Bob]

Also - the boxes must meet third party certification for installation - sometimes the requirements are generally mentioned in the code but the LISTING of the device will indicate what is required for the box to meet it's listing requirement -

http://ul.com/wp-content/uploads/2014/04/Ul_outletboxes.pdf