Quiz: Main breaker panel box mounting

Greetings to all you good folks!

I was walking through a new three story apartment constrution project today and was surprised to find that the 2x4 studs measured 3 3/8", but many measured 3 1/4" or less, by 1 7/16" and a bit less. Several stages of construction are in progress - the site when complete will have 16 buildings housing 24 apartments each.

Of course, many questionable things were seen but I wonder most about the breaker panels - one for each apartment. Before sheetrock is installed, I can see that the back of these panels with have no breathing space. The backside of the panel may be facing into a living room or another bedroom. The user side of the panel is in a bedroom, but not a closet.

Does the backside need to be a fire rated sheetrock? If the studs were 3 5/8 or 3 1/2" the panel back would not be touching the sheetrock. Is this anything to be concerned about? (I am not doing a for-pay inspection, just nosing around to see how things have been done.) What do you think? is it okay and should I stick my nose where it doesn’t belong if it is not okay?

Thanks :slight_smile: :smiley:



I would not be overly concerned on this. Sheetrock in itself is considered non-combustible in the installation case…and as for the space behind it…that usually applies to surface mounts on cinderblock and concrete to allow air space to reduce moisture build up and corrosion.

I would not be overly concerned here…


Judging from you credentials, I have all the answer I need. Thanks a bunch - how nice it is to get a quick expert answer! :smiley: :smiley: :smiley:

**Just for future sake…here is the airspace reference in regards to wet and damp locations…may come in handy for ya.

**312.2 Damp, Wet, or Hazardous (Classified) Locations.
(A) Damp and Wet Locations. **

In damp or wet locations,
surface-type enclosures within the scope of this article shall be
placed or equipped so as to prevent moisture or water from
entering and accumulating within the cabinet or cutout box,
and shall be mounted so there is at least 6-mm (1⁄4-in.) airspace
between the enclosure and the wall or other supporting surface.
Enclosures installed in wet locations shall be weatherproof.
For enclosures in wet locations, raceways or cables
entering above the level of uninsulated live parts shall use
fittings listed for wet locations.

good stuff, thanks! Does it matter that these are flush mount panels?

If you are refering to can they set back into the wall…well if the wall is sheetrock or gypsum which it is called sometimes then it can set back up to 1/4"…BUT if the covering is combustible like wood paneling and so on…or simular then it has to be flush with the outside wall.

Most of the time when someone sets it back into the wall and it does not end up flush…or has a depth more than 1/4" at the finish…it also causes a problem with the breakers fitting into the cover right and leaving GAPS that have to be addressed…so out of a courtesy you may want to let them know about that…but again if the walls are gypsum or sheetrock finishes walls then it can set back up to 1/4" without any problems.

…but again if the walls are gypsum or sheetrock finishes walls then it can set back up to 1/4" without any problems.
Paul Abernathy,CME,RMS,CMI

**Thanks Paul. **
Without pictures it is difficult to communicate some intricateness’s so I have to ask what you mean “…it can set back …” Does this mean that the back surface of the electrical panel must be 1/4" from the back face of the sheetrock of its shared stud wall? :neutral:


No. The back of the panel has no restrictions as to “breathing space”.

What Paul means is the front leading edge of the panel (where the cover screws on) can be 1/4" set back from the finish sheetrock.

AS Speedy nicely added…talking about the front…not the back of the panel…

Thanks, I appreciate the advice.