# 100 KAIC panel for a 62 KAIC service?



## Yikes (May 23, 2011)

The dept of water and power said they will supply my 1600 amp apartment switchgear (208Y, 120V, 3 phase, 4 wire) with a max fault current of 62KAIC.  The motor contribution brings it up to 63.66 KAIC.

We originally spec'd a 65 KAIC panel, but the plan checker is saying we must provide a 100KAIC panel, for an additional factor of safety.  Can he legitimately require something that goes beyond the requirements of the DWP and the engineer of record, and the calculated loads?  If so, why?

At this stage of the project, we can't afford the switchgear upcharge, nor the opportunity for supplier to revisit their price quote.


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## Bryan Holland (May 24, 2011)

I say no.  There is no "additional factor of safety" section of the NEC.  The 65K equipment satisfies Section 110.9 of the NEC.  No "additional" considerations are needed.  The maximum possible fault current cannot and will not exceed 65,000 amperes so equipment with a higher rating is not necessary and will serve no purpose...


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## raider1 (May 24, 2011)

I agree with Bryan, there is no safety factor required by the NEC. 110.9 requires the AIC rating of the equipment to meet or exceed the available fault current.

Chris


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## peach (May 24, 2011)

ummmmmmmmmmmm no. unless they have a policy..


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## chris kennedy (May 24, 2011)

Yikes said:
			
		

> The dept of water and power said they will supply my 1600 amp apartment switchgear (208Y, 120V, 3 phase, 4 wire) with a max fault current of 62KAIC.  The motor contribution brings it up to 63.66 KAIC.


I certainly agree with Bryan and Chris that this is not an NEC issue.

I do find this odd though. Here for a service as mentioned, POCO would supply tranny specs and a primary at infinity. They don't do secondary fault current calcs for us. 62K seems high to me unless the tranny is sitting on top of your service gear. So I question have your done your own calc on this? Could be an option to expedite this through plans review.


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