110.26(C)(3) - 800A Main Panel with 600A MCB.

[ElectricClimber]

Long time reader (4.5 years), first time poster. If this is in the wrong spot, please feel free to move.

Curious of other's interpretation of 110.26(C)(3). Would this apply if an 800A rated MDP is used with a 600A MCB?

110.26(C)(3) reads: Where equipment rated for 800 amperes or more that contains overcurrent devices, switching devices, or control devices is installed and there is a personnel door(s) intended for entrance to or egress from the working space less than 7.6m (25ft) from the nearest edge of the working space, the door(s) shall open in the direction of egress and be equipped with listed panic hardware or listed fire exist hardware.

My thought would be yes based on text above. I have 800A rated equipment with overcurrent protective devices in it which would require the listed panic hardware. On the other hand, the max capacity of the service conductors and main breaker are only rated for 600A so there is not 800A available.

 

[augie47]

I would consider it a 600 amp panel

 

[don_resqcapt19]

In my opinion, the equipment rating is that of the main busing, and would be 800 amps in this case.

 

[petersonra]

I would consider it a 600 amp panel

IMO, bus work that is part of a listed assembly would not qualify as "equipment", so the equipment rating would be 600 Amps if there is a 600 Amp rated OCPD installed. If it was a MLO panel, than IMO it is rated at 800 Amps, regardless of the upstream OCPD rating.

 

[ElectricClimber]

I appreciate the discussion. Other engineer's in my company had similar opinions on both sides. Seems it may be best to error on the more strict interpretation and install panic hardware or get the local AHJ interpretation ahead of time.

 

[brantmacga]

On the other hand, the max capacity of the service conductors and main breaker are only rated for 600A so there is not 800A available.

I would consider that a 600A panel. I would at least ask why they're using an 800A rated interior. Maybe it was only to support a particular frame circuit breaker, or AIC rating? I don't have any specific examples right off but I know there are times when my supplier is building out a panel assembly, they'll call me to say they had to go to a larger size cabinet/interior etc to make certain breaker combinations work.

 

[charlie b]

I agree with Don. As described, this is an 800 Amp panel.

That said, what makes you think the panel, specifically the bus work, is rated for 800 amps? Perhaps a label placed by the manufacturer? That can be changed, though I don't know whether you need them to participate in the change.

I am not suggesting cheating in any way. Many manufacturers will build two identical products, give them labels with different ratings, and sell them at different prices and with different paperwork, as though they were, in fact, built differently.

Bottom line: change the label to call it a 600 Amp panel, and the issue disappears.