Generator OCPD W/GFI

[blues]

I have a 3000 ampere service @ 480/277V, 3ph, 4 wire. The MDP has a 3000amp main with ground-fault protections. There is also a generator for full service back up. My question is since this genset is a separately derived system @ 480/277V and 3000amp CB. Is the generator breaker required to be GF type as well. I am thinking yes. But want to sure before we spent dollars.

 

[texie]

I have a 3000 ampere service @ 480/277V, 3ph, 4 wire. The MDP has a 3000amp main with ground-fault protections. There is also a generator for full service back up. My question is since this genset is a separately derived system @ 480/277V and 3000amp CB. Is the generator breaker required to be GF type as well. I am thinking yes. But want to sure before we spent dollars.

Your drawing implies a strictly 702 optional system with no 700 loads. That looks to me to say the 3000 amp genset breaker will have to be GFPE.

 

[kingpb]

Is it a separately derived system? I assume you are saying the transfer switch is 4-pole; i.e. switching neutral?

 

[kingpb]

If this is an industrial process, GFP is not required. I would also consider asking the design engineer if a neutral is necessary. According to the SLD it may not, eliminating the neutral will remove the GFP requirement and eliminate some cable.

 

[texie]

If this is an industrial process, GFP is not required. I would also consider asking the design engineer if a neutral is necessary. According to the SLD it may not, eliminating the neutral will remove the GFP requirement and eliminate some cable.

I would agree that there may be an exception for SOME industrial processes but if it is determined that GFPE is required and it is a 480Y grounded system, removing the neutral will not alleviate the GFPE requirement.