Dedicated space for electrical equipment

[seanote]

It appears that this requirement is most often applied to surface mounted equipment and is clear about this space being dedicated. We have recently been tasked by an AHJ to keep this same space clear of systems foriegn to the electrical for equipment (panelboards) fllush mounted in walls. This is the first time in my experience that this requirement has been applied to fllush mounted panelboards. Curious as to the experience of others in this regard.

 

[don_resqcapt19]

So the wall does not have a top plate?
The code section is poorly written and the words as in the code now would actually prohibit the installation of flush mount panels. We know that is not the intent, but once again the words in the document do not match the intent of the rule. That being said, I have never heard of an inspector actually applying the rules to a flush installation.

 

[kwired]

So the wall does not have a top plate?
The code section is poorly written and the words as in the code now would actually prohibit the installation of flush mount panels. We know that is not the intent, but once again the words in the document do not match the intent of the rule. That being said, I have never heard of an inspector actually applying the rules to a flush installation.

I have to agree. I have seen leniency of this in flush applications, but you don't get away with any foreign object in a surface installation. IMO the flush installation is the one that it going to be more difficult to install additional raceways or cables sometime down the road than the surface installation with some foreign object in that space.

 

[charlie b]

The code does not prohibit having "foreign objects" above or below a panel. What it forbids is "equipment foreign to the installation." IMO, no part of a wall, including the top plate, would meet the defintion of "equipment." So the dedicated equipment space rule, however badly written, does not prohibit installing flush mounted panels. I have had to work with a plumbing engineer to get his pipes routed in such a way that they didn't run over or under a flush mounted panel. So that part of the code still applies inside the wall.

 

[kwired]

I have had to work with a plumbing engineer to get his pipes routed in such a way that they didn't run over or under a flush mounted panel. So that part of the code still applies inside the wall.

I agree that part still applies inside a wall. But I think many will tell you it gets overlooked more when in a wall than when the electrical install is surface mounted. And as I said, the flush mount is the situation where it generally will be more difficult to install additional raceways or cables down the road than it would be for surface mount, so we are not doing ourselves any favors by allowing foreign objects in those flush installs.

I still am somewhat a firm believer of surface mounting and placing in a mechanical room as much as possible instead of flush mounting in other areas.

 

[don_resqcapt19]

The code does not prohibit having "foreign objects" above or below a panel. What it forbids is "equipment foreign to the installation." IMO, no part of a wall, including the top plate, would meet the defintion of "equipment." So the dedicated equipment space rule, however badly written, does not prohibit installing flush mounted panels. I have had to work with a plumbing engineer to get his pipes routed in such a way that they didn't run over or under a flush mounted panel. So that part of the code still applies inside the wall.

If the rule only applies to "foreign" equipment, then why did the CMP choose to include the following exception?

Exception: Suspended ceilings with removable panels shall be permitted within the 1.8-m (6-ft) zone.

 

[GoldDigger]

If the rule only applies to "foreign" equipment, then why did the CMP choose to include the following exception?

[suspended ceiling allowed]

A good logical question.

My take is that the scope of equipment foreign to the electrical installation is fairly broad, and would definitely include things like plumbing inside the wall, and potentially even firestops which cross the stud bay above or below the flush mounted electrical equipment but are not directly supporting it.

The top plate is a very minimal intrusion, since it could be considered part of the structural ceiling itself, and therefore outside the zone. It is certainly structural!

We know that a suspended ceiling is explicitly not considered structural, and in fact the drywall of a fixed chase below a concrete ceiling is not structural either.

2011:

110.26(E)(1)(a) Dedicated Electrical Space. The space equal to the width and depth of the equipment and extending from the floor to a height of 1.8 m (6 ft) above the equipment or to the structural ceiling, whichever is lower, shall be dedicated to the electrical installation. No piping, ducts, leak protection apparatus, or other equipment foreign to the electrical installation shall be located in this zone.

 

[infinity]

If the rule only applies to "foreign" equipment, then why did the CMP choose to include the following exception?

They're as confused as the rest of us.