Separate comm. buildngs on separate services PV on one building serving the other

[earshavewalls]

I have a first, for me, in 10 years of reviewing PV installations. This one is a commercial installation on one building with two separate PV systems....one serves the building whose roof it is installed on but the other is to be interconnected at the service on the other, separate building, which is 32-feet separated from the building with the PV.
I looked through the Code but could not find anything related to PV interconnections that allowed or prohibited this configuration.
My concern is with a few items:
1) Rapid shutdown
2) Automatic shutdown with power loss to service

It seems to me that some sort of RSD needs to be provided to shutdown these systems simultaneously, but nothing has been provided.
Has anyone seen this? Is it even legal? Code articles?
I feel that I need to require some special protections, but cannot find any Code basis (which I must have).

Thanks,
Wayne Webb
MEP/Energy Plans Examiner
California (Please reference 2016 CEC or 2014 NEC)

 

[jaggedben]

I don't think it's illegal. (If the buildings are on separate parcels then perhaps there should be some kind of easement written up, but that's outside the scope of the NEC.)

I agree with you about Rapid Shutdown except for the 'simultaneously' part. 2014 Rapid Shutdown requirements are entirely vague about how many switches are allowed/required. I think it would be reasonable to ask for the controls to be grouped if there isn't a good reason for them not to be, but see below.

Automatic power shutdown to the building with power loss to service just isn't a code requirement. (for example, stand-alone and backup generators of various types are allowed.)

If I were you, my approach would probably be to require really clear, durable placards to fulfill 690.56(C) and 705.10. That is the best recourse to make sure anyone who needs to understand the systems in a hurry can do so. I don't think there's any justification for denying the overall concept.

 

[ggunn]

I don't think it's illegal. (If the buildings are on separate parcels then perhaps there should be some kind of easement written up, but that's outside the scope of the NEC.)

I agree with you about Rapid Shutdown except for the 'simultaneously' part. 2014 Rapid Shutdown requirements are entirely vague about how many switches are allowed/required. I think it would be reasonable to ask for the controls to be grouped if there isn't a good reason for them not to be, but see below.

Automatic power shutdown to the building with power loss to service just isn't a code requirement. (for example, stand-alone and backup generators of various types are allowed.)

If I were you, my approach would probably be to require really clear, durable placards to fulfill 690.56(C) and 705.10. That is the best recourse to make sure anyone who needs to understand the systems in a hurry can do so. I don't think there's any justification for denying the overall concept.

I agree; I'll just add that if there is a chance that the buildings could ever be sold separately things could get sticky.

 

[pv_n00b]

This situation is not specifically covered by the 2014 or 2017 NEC, and I doubt that will change with the 2020 NEC. There are always these edge cases that can exist but are in such a small number it's not worth complicating the code to cover. So roll your own here.

I would at least require a placard at the PV AC disconnect of the building with the 2 systems saying that one of the systems is connected to a service at the other building and needs to be shut down from there. The next step up would be to require an AC disconnect for both systems on the building with the systems. It just means an extra disconnect for the system going to the service in the adjacent building. Hardly an onerous requirement.

 

[earshavewalls]

Thanks for all of the input. I'm on the same page, I just wondered if anyone had dealt with this situation. I will proceed with requiring safety features and placards, in my own "roll", and we'll see how it goes. I have a teleconference set up today with the electrical engineer, so we'll work it out.
I think I will recommend a document to be placed in the property file concerning the situation that could/would arise if the parcel was split (currently under single management).

Thanks again!

Wayne Webb
ICC Commercial Electrical Inspector
ICC Electrical Plans Examiner
ICC Building Plans Examiner
California Building Plans Examiner

 

[ggunn]

I had a similar situation; it was a 820kW system split between a hospital and the parking garage across the alley from it and interconnected in the hospital electrical room. We had to have a disco at ground level on the garage exterior as well as one at the interconnection point, and placards everywhere.