Generator transfer

[E.Hall]

Is there a time limit in which a transfer switch has to transfer power from the time regular power is droped? I had an inspector fail me on a final inspection because power transfered in 13 sec. and not 10 sec. The building is a warehouse. Is that in the NEC?

 

[iwire]

Yes it is in the NEC if it is really an emergency generator.

III. Sources of Power
700.12 General Requirements. Current supply shall be
such that, in the event of failure of the normal supply to, or
within, the building or group of buildings concerned, emergency
lighting, emergency power, or both shall be available
within the time required for the application but not to exceed
10 seconds. ..............

If it is an optional standby unit then no time limit applies.

 

[RICK NAPIER]

This is one reason buildings with generators use battery backed emergency lights. The lights are the only required emergency circuits in the building often and turn on within the ten seconds even if the generator does not.

 

[Hendrix]

Is there a time limit in which a transfer switch has to transfer power from the time regular power is droped? I had an inspector fail me on a final inspection because power transfered in 13 sec. and not 10 sec. The building is a warehouse. Is that in the NEC?

I doubt that a warehouse would need emergency power so I would say no.

 

[ceb58]

As everyone has stated How is the generator categorized? Emergency, legally required or optional? Art 700,as Bob posted, must crank and transfer not to exceed 10sec. Art 701 for a legally required is not to exceed 1 min.