Emergency Generator feeding Life Safety and Standby Loads

[Platinum2012]

This deals with 700.9.
I have an emergency generator with 1 output breaker which powers a generator distribution panel (GDP). From the GDP i have a separate branch breaker feeding an ATS-LS (life safety) and another branch breaker feeding an ATS-SB (standby loads).

This GDP has to have separte vertical sections correct? Something like a switchboard or an MCC?

The contractor is suggesting to split the GDP into 2 separate panelboards (1 for LS and 1 for SB). In other words, the main generator feeder goes into the Stand-by panel and then feeds-thru to the Life Safety panel. Does this violate 700.9?

Any info would be appreciated...

 

[kingpb]

This deals with 700.9.
I have an emergency generator with 1 output breaker which powers a generator distribution panel (GDP). From the GDP i have a separate branch breaker feeding an ATS-LS (life safety) and another branch breaker feeding an ATS-SB (standby loads).

This GDP has to have separate vertical sections correct? Something like a switchboard or an MCC?

Yep, I would agree in principle, although it only mentions switchboards, not MCC's.

The contractor is suggesting to split the GDP into 2 separate panelboards (1 for LS and 1 for SB). In other words, the main generator feeder goes into the Stand-by panel and then feeds-thru to the Life Safety panel. Does this violate 700.9?

I believe the Contractor is misinterpreting the NEC and the setup would have to have a common bus, not a feed-thru. I would think you could use two panelboards with main breakers in each mounted side by side, and tap off the gen circuit to each of them.

 

[Platinum2012]

Yeah the contractor is trying to find a way out of purchasing a vertical switchboard...

I did suggest using an MCC since it would be cheaper than a switchboard. The feeder sizes from this GDP are small, only 100A feeds, so i'm thinking a standard MCC bucket would handle a 100A breaker just fine.

So you are saying from the emergency generator we should set up some kind of wire gutter box (which would be our common bus) and from that you would tap your Life-Safety panel (with MCB) and Stand-by panel (with MCB)?

 

[dkidd]

look at document

0110DB0901 Emergency System Generators and Circuit Wiring

at

http://www.schneider-electric.us/si...echnical-library/applications/generators.page

 

[Wyeman94]

don't forget the transfer

don't forget the transfer

Great reference dkidd.

I agree feed-thru is a violation, but what about the transfer switches? I'm curious as to where they are intended to be placed in the circuit if you were to "split up" the Generator Distribution Panel.