Separate Interconnection for PV System on Multiple Buildings

[cyriousn]

Is there anyone that might be able to sanity check me on a system layout I'm looking at under 2020 NEC adoption.

The property the system is on is a self storage facility with 10 separate buildings.
Each building has a different roof area so different DC Wattage ranging from 26kw to 122kw.
Each building would have its own dedicated inverter with rapid shutdown.
AC circuits from each building would go to a equipment pad with a 480V switchboard and Transformer.
12.47kv Line would go to the street.

Two items have caught my attention though, the first is the buildings will all be fed from a separate electrical service for lighting and plug loads. Since the PV circuits won't be going into the buildings I think we are okay there... The second thing is I'm unsure if we could run DC circuits from one building to another to reduce the number of inverters? I'm worried that an AHJ will want to have the rapid shutdown + disconnecting means on the buildings they are serving. I think we will need to reach out to the AHJ either way but figured I'd throw this out there. Thanks all.

 

[BandGap1.1eV]

No issue with doing what you intend, to the best of my understanding. If he wants a Rapid Shutdown Initiation Device on each building you can put an EPO button there that shunts the main breaker in the combiner panel. If he wants an open blade disconnect on each building, that's another conversation.

 

[ggunn]

The second thing is I'm unsure if we could run DC circuits from one building to another to reduce the number of inverters? I'm worried that an AHJ will want to have the rapid shutdown + disconnecting means on the buildings they are serving. I think we will need to reach out to the AHJ either way but figured I'd throw this out there. Thanks all.

In my experience, some AHJs have allowed it and others have not. Mostly not, IIRC.

 

[jaggedben]

I think the answer to the rapid shutdown question depends on how exactly the rapid shutdown technology works.

Otherwise I see nothing wrong. 230.2(A)(5) and 225.30(A)(5) explicitly permit an additional service or feeder for the PV system.

 

[cyriousn]

Thank you everyone for your responses. Time to schedule that AHJ meeting!

 

[ggunn]

I think the answer to the rapid shutdown question depends on how exactly the rapid shutdown technology works.

Otherwise I see nothing wrong. 230.2(A)(5) and 225.30(A)(5) explicitly permit an additional service or feeder for the PV system.

But I advise clearing it with the AHJ before construction.

Sorry for the late entry; I wrote it yesterday but forgot to hit the button to post it.