Sparky2791
Senior Member
- Location
- Northeast, PA
- Occupation
- Electrical Design
Hello.
I am very confused and have spent the last 2 hours going in circles.
My scenario.
Some background
NEC 2014 is enforced in my state.
Electric service and stand-by generator are both 277/480V 3 phase Wye connected.
I have an existing 55KW emergency generator installed on an existing 800A service so no GFP is provided on the main service. We are upgrading the service to a 2000A service which will now have GFP. Because of this I need to replace the existing 3 pole transfer switch with a 4 pole transfer switch for proper operation of the new GFP. I am trying to determine the proper way to set this generator up as a separately derived system with respect to the grounding. To make matters more interesting this is an exterior generator on a concrete pad about 30’ from the door to the main electric room. There is currently an 100A -3P circuit breaker installed on the generator which feeds a 3 pole transfer switch inside the building. I have reviewed the NEC specifically 250.30. I was wondering since I need to follow 250.30 and the gen set is installed outside how do we comply? I imagine there will be questions first so Ill answer whatever is needed first. Thanks for responding!
I am very confused and have spent the last 2 hours going in circles.
My scenario.
Some background
NEC 2014 is enforced in my state.
Electric service and stand-by generator are both 277/480V 3 phase Wye connected.
I have an existing 55KW emergency generator installed on an existing 800A service so no GFP is provided on the main service. We are upgrading the service to a 2000A service which will now have GFP. Because of this I need to replace the existing 3 pole transfer switch with a 4 pole transfer switch for proper operation of the new GFP. I am trying to determine the proper way to set this generator up as a separately derived system with respect to the grounding. To make matters more interesting this is an exterior generator on a concrete pad about 30’ from the door to the main electric room. There is currently an 100A -3P circuit breaker installed on the generator which feeds a 3 pole transfer switch inside the building. I have reviewed the NEC specifically 250.30. I was wondering since I need to follow 250.30 and the gen set is installed outside how do we comply? I imagine there will be questions first so Ill answer whatever is needed first. Thanks for responding!
