Flush Mounted Panelboard In Existing Masonry Wall

[pharouff]

There is not enough clearance to surface mount a 480V panelboard on an existing masonry wall (non-load-bearing). We are planning to cut a section of the wall, frame the opening, and fur out with sheetrock to install flush-mounted electrical panelboards.

The wall construction would probably not be considered a "foreign system", but the NEC Handbook states that the intent of 110.26(F)(1) is to allow access for installation of busways, raceways, conduits, and cables connecting to the panelboard. Everyone would probably agree that flush mounting in a masonry wall would not make installation of branch circuits easy unless some additional accommodations are provided. Unfortunately, the examples provided in the NEC Handbook depict only surface mounted panelboards, so there is no official interpretation.

Question 1 (Practical): How should the area inside a wall located above a flush-mounted (recessed) panelboard be treated to comply with the "dedicated electrical space" requirement in 110.26(F)(1)(a)? Should I tell the contractor that the framed hole must extend at least 6 feet above the electrical panelboard? Is sheetrock acceptable, or is a gutter with access panel required?

Question 2 (Theoretical): Using a strict interpretation of 110.26(F) (which has been used by some to mandate that all panelboards must be inside electrical closets), the term "dedicated space" may not include a space within a wall. Also, while suspended ceilings are specifically exempted under 110.26(F)(1)(a), sheetrock and framing members are not and would theoretically be prohibited within the "dedicated electrical space" unless they are part of a structural ceiling. Therefore, are panelboards flush-mounted inside walls without a gutter and access panel permitted under the current NEC requirements?

 

[Dennis Alwon]

I don't believe 110.26 has anything to do with access for future circuits and a recessed panel does not need to have the clearance as you stated. There cannot be water pipes etc that can drip into the panel running in the space.

 

[Rewire]

I think you are mis reading the code the dedicated space is the footprint of the panel here is a link to n old discussion
http://forums.mikeholt.com/showthread.php?t=123969&p=1177110#post1177110

 

[steve66]

The theoretical question is interesting. However, given the number of flush mounted panelboards made and installed, I think we can safely assume the intent was never to prohibit flush mounted panelboards just because the wall might be an obstruction.

As a practical solution, I would suggest specifying some spare conduits coming out of the top of the panel up through the top of the wall. Then you have allowed future branch circuits to be added without major rennovations.