NEC 110.24

[mannyb]

we are bidding 10k square building with 3000a service. The drawings provide no fault calculations for 110.24 or any calculations for 110.16 a or b. If the engineer hasnt provided neither and the EC is to provide as part of the bid what do you guys recommend to use like a software or do you recommend subbing that portion of work?

 

[jeremy.zinkofsky]

we are bidding 10k square building with 3000a service. The drawings provide no fault calculations for 110.24 or any calculations for 110.16 a or b. If the engineer hasnt provided neither and the EC is to provide as part of the bid what do you guys recommend to use like a software or do you recommend subbing that portion of work?

Either SKM or ETAP. If i am not mistaken, you are only required to mark the service equipment. This can be done with a single calculation for available short circuit current using the exact utility transformer impedance, secondary cable size/length, system voltage, etc. Utilize the infinite bus method unless you can get actual utility amps for the provider.