Automatic Transfer Switch with Dual Service Entrance?

[Darksabre]

Hey all - looking to hopefully learn something about service entrance.

We had a customer reach out and request a service entrance-rated (without ground fault) contactor-based automatic transfer switch (ATS) with OCPD's on both the utility and the generator side. This is the first I've heard of this request and cannot find any examples in books or forums of this. They specified the ATS to be 3-pole (solid neutral).

The only relevant code I could find is in UL 1008 8.1.2.7. It states: "In a transfer switch intended for use as service equipment, having a service disconnect for both the normal and alternate supplies, each of the service disconnects shall be located in a separate compartment." so there must be someone doing this out there for some reason.

Questions that come up in my mind are:
1. Why would someone want (or need?) to do this? Just a convenient place for both disconnects?
2. To meet code, we provide a neutral-to-ground bond jumper at the utility service entrance side. They want a 3-pole ATS, so the neutral is solid between the utility and generator. Does having a single neutral bond but two service entrance breakers cause any issues here?
3. We provide a keyed service disconnect switch on the door to electrically trip open the SE breaker. Should the service disconnect switch disconnect both breakers? Should there be a separate keyed switch for each breaker? Or is it just customer preference at that point? I can't find any code that addresses this.

 

[ptonsparky]

Maybe this is too simple, but a SE rated equipment does not have to be used only for Service Entrances. You don't have to bond the neutral at the ATS.
Don't most Generators have a breaker?

My experience level is limited.

 

[Darksabre]

Maybe this is too simple, but a SE rated equipment does not have to be used only for Service Entrances. You don't have to bond the neutral at the ATS.
Don't most Generators have a breaker?

My experience level is limited.

That was my understanding as well - most (all?) generators have a breaker to disconnect and protect. I remember reading somewhere that you can have the generator side of the ATS be rated for service entrance if, and only if, it is the first disconnect means between the ATS and generator.