PV only service

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There's an advantage to the way it is (but not PV only) that you are forgetting. The PV System disconnect (that you are calling a service disconnect) is not required to be grouped with any actual service disconnect. If you chamge to call it a service disconnect, then it would be required to be grouped with others. That said, I realize some POCO's and/or AHJ's may require it to be grouped anyway...

Ok good point, I missed that. Wait a sec though, doesn't it still have to be grouped with the "normal" service disconnects? 230.71 mentions the "service disconnecting means........or for each set of service entrance conductors permitted by 230.40.......ex #5" , and then 230.72 states, "the two to six disconnects as permitted in 230.71 shall be grouped." No?

Even if I am reading that wrong, I still say it would be more logical to delete 230.82(6) and 230.40 Ex #5 and simply add en exception in the appropriate spot allowing a Disconnecting means serving solely a PV system to not be grouped with any other service disconnecting means.
 

jaggedben

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Solar and Energy Storage Installer
There's an advantage to the way it is (but not PV only) that you are forgetting. The PV System disconnect (that you are calling a service disconnect) is not required to be grouped with any actual service disconnect. If you chamge to call it a service disconnect, then it would be required to be grouped with others.

Calling it a service disconnect changes nothing, because it fits under 230.40 Exception 5, which (unlike Exception 2!) is one of those sets of service conductors that is 'each' given its own allowance of up to 6 disconnets by 230.71(A).

But yes, that is reason for not getting rid of 230.82(6).
 

jaggedben

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Northern California
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Solar and Energy Storage Installer
Even if I am reading that wrong, I still say it would be more logical to delete 230.82(6) and 230.40 Ex #5 and simply add en exception in the appropriate spot allowing a Disconnecting means serving solely a PV system to not be grouped with any other service disconnecting means.

In principle I have no objection to that, but I think some people who install systems under 230.82(5) would not want to be forgotten.

There's another issue, as well, which is defining the ampacity rules for supply side connections. Which is why, I think, no matter what you do to Article 230, 705.12(A) needs to stay. So much for "getting rid of 'supply side connections' ".
 
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shortcircuit2

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I am working on a 1 MW PV installation which got me thinking about a few things. For the purpose of this discussion, assume the NEC applies here. I was having a discussion with a coworker about a few code violations the engineer made. One was that he didnt upsize the feeder EGC's proportionate to the ungrounded conductors which had been upsized for voltage drop. The coworker said there was an exception to that rule for PV and I stated but that the feeder wasnt part of that exception. Anyway, that got me thinking about this broader question: Is there anything different about a service or feeder that contains ONLY PV generation and no loads? I say no, except for indirect consequences such as 705.12(D)(3)(c). Similarly, is there anything special about a PV line side tap? I say no its just adding another set of service entrance conductors and an additional service disconnecting means correct? I see no purpose to 230.82(6). Does anyone disagree with this?

I agree. I see no purpose for 230.82(6) either. The language in 230.82(6) could be added to 230.82(5)...but add wind systems also as we did in Massachusetts in our amendments. Rewrite 230.40 exception #5 to reflect the change. Remove 705.31 and this new 10ft rule altogether. We can't run un-fused service entrance conductors that distance in a building for any other reason so why should the hazard be allowed under this rule?
 

ggunn

PE (Electrical), NABCEP certified
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Electrical Engineer - Photovoltaic Systems
No, but they are often used to implement a disconnect which also requires OCPD.
I know we aren't supposed to use a CB that has line and load distinctions stamped on it for interconnecting PV, but I have never seen one. I assume they exist.
 
There's an advantage to the way it is (but not PV only) that you are forgetting. The PV System disconnect (that you are calling a service disconnect) is not required to be grouped with any actual service disconnect. If you chamge to call it a service disconnect, then it would be required to be grouped with others. That said, I realize some POCO's and/or AHJ's may require it to be grouped anyway...

Ok I see it now. The "PV disconnect" allowance gives you no grouping requirement with the "normal" service disconnects and you could have 6 if you needed. Until I read 230.71 eleven times I thought they had to be grouped.

jaggedben said:
There's another issue, as well, which is defining the ampacity rules for supply side connections.

Can you elaborate a bit on this and its implications? Thanks
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Can you elaborate a bit on this and its implications? Thanks

Just that since the 2011 code, 705.12(A) is where we have the rule that you can connect power sources adding up to the rating of the service. And also that if this were taken out and you had only the load side rules, a lot of AHJs would be extremely confused. I have enough trouble explaining supply-side connections to AHJs while having this right there with the other rules. If you think there could be clearer language than "supply side connection" then have it, but I think you need the rule to be stated in 705, whatever it is.
 
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