Two Electrical Boxes in the Same Stud Cavity?

8/19/2022

Can two electrical boxes be placed in the same stud cavity?

If so, are there restrictions by code?

Thanks in advance.

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4 Comments

Adam

8/19/2022 08:26:20 am

I'm assuming this is in a fire-rated wall, and the boxes are on opposite sides of the wall within the same stud cavity.

In Ontario you can do this, but additional framing must be installed to separate the two boxes.

If they are at different heights, such as a receptacle at the floor on one side, and a light switch on the opposite side, a piece of horizontal lumber spanning the stud cavity is easy enough to provide.

If they are at the same level, a complete box would need to be provided. This is often a horizontal piece spanning the stud cavity, and then a vertical piece extending from the bottom plate to the horizontal piece. It is often much easier, and preferred to just relocate one box.

David Toshio Williams

8/19/2022 04:08:59 pm

Better to have them in separate stud cavities, but even there you have to be sure the studs create the proper fire separation. The wall assembly as identified in the UL (or other) listing should help you with the required separation.

There are also fire resistive "pad" kits to cover the boxes if you must be in the same stud cavity (all subject to the listing of the product and wall and approval by the AHJ).

sean

8/20/2022 06:39:52 am

If in a rated wall in the same cavity you can use a rated fire stopping system (putty pads) to restore the rating.

Jim Sills

5/3/2024 08:25:06 am

https://code-authorities.ul.com/wp-content/uploads/2014/04/Ul_outletboxes.pdf

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Two Electrical Boxes in the Same Stud Cavity?

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