Switchgear and fully rated breakers

[ron]

Please help me determine if there is a code violation.
UL 1558 listed Switchgear rated at 4000A.
At its worst case, which will probably never be reached, continuous load provided by several 100% rated feeder breakers totals 3,900A.

Switchgear is listed as 100% rated per the UL Listing and the breakers seem ok per the exception for 215.2(A)(1).

What do you think?

 

[kingpb]

Switchgear can be operated up to its full rating without damage. No need to derate, as you already determined.

The protection will need to be selected based on FLA and short circuit availability.

Cable will obviously have to be fully rated for 4000A as well.

 

[steve66]

If the loads are motors, 220.18 refers you to article 430 which says feeders should be rated for the full load current of all motors running, plus 25% of the largest motor. So you are OK if 25% of the largest motor is 100A or less.

If it is more than 100A, look at 430.26. It looks to me like that gives the AHJ the authority to approve installations like this.

Steve

 

[ron]

No motors, just lots and lots of computers.

 

[Pierre C Belarge]

Ron
Are you planning on a full size neutral for the service supply?

100% rated circuit breakers? Those are some pretty big feeders. What size are those 100% rated circuit breakers?

I am not questioning your proposed setup, I am just curious about this installation. It is seldom seen to have 100% rated circuit breakers. What kind of building does this supply? Those breakers are big $$$.