Since most large switchboards placed along a wall tend to be positioned at least a few inches off/away from said wall, does the code allow foreign equipment to be mounted within this gap and under 6' above the electrical equipment? Tecnically, nothing placed within this gap would be within the "footprint" of the gear. Obviously, at some point, the gap does become large enough for other trades to use. Is it one inch, three inches, one foot? Can the AHJ say that even 18" isn't enough?
The working space is only in front of the type of equipment I am referring to. For equipment requiring working space behind it, the unit would not be allowed to be placed up against a wall. Sorry, I don't think I described the situation very clearly.
I really think the AHJ needs to weigh in on this. A drain line behind the equipment will cause few problems, a water line could sweat or break, a gas line is a hazard next to electrical equipment. You also have to consider how you would repair/replace something that is rendered inaccessible after installation. The 2 of you need to go over the specifics of this installation...I doubt that there is a universal answer to this.
1) The area I am referring to is above the equipment, within six feet vertically of its top, but behind the footprint. If the equipment were 6' from the wall instead of 4" then there would definately be no problem with anything foreign being installed there. 2) Nothing is rendered inaccessible. Again, I must not have described the scenario well. Nothing has been placed directly behind the switchgear. It it above but behind the footprint.
Agreed. I had a major switchgear installation where the Contractor took a short cut and routed the incoming natural gas line over the gear. His response to the AHJ's objection was to put a drip pan underneath the gas pipe.