Question about Supply Side PV interconnects and 2014 NEC Article 230.6

[MTPR220]

Hey there,
I have a proposed solar supply-side interconnection for a commercial building into an existing piece of switchboard. The roof-mounted PV inverters will land at a combiner box and main PV disconnect just outside the electric room at grade. From there, the PV will punch through the wall and enter the top of the main switchboard to land via a supply-side bus tap with cable limiters (behind the meter or ahead of the main). The gear is located in the center of the room. The AHJ (citing the adopted 2014 NEC) has insisted on the following: "Service entrance conductors are run inside the building from the main switchboard to PV disconnect ACD-1. Please demonstrate how the contractor will comply with Art. 230.6". I am not sure this would apply here, and if it did, then the majority of supply-side installations I have seen in my 13+ years would not be permitted. From 230.6, the implication would be that we need to bring our conductors in beneath the building foundation and up through the bottom of the gear, or provide a concrete or masonry chase to the gear. This seems like overkill and impractical at best. Would 230.6 really apply to the PV interconnection here? Are these considered service conductors or service entrance conductors? Are there other exceptions or permissions I can cite for this type of installation? Thanks in advance, and let me know if I can clarify anything.

 

[jaggedben]

The categorization of those conductors has been vauge for a long time. In the 2023 NEC things have finally come around to seeing them as service conductors. However if the governing code is the 2014 NEC then there's still some ambiguity.

That said, I agree with you that the way the relevant parts of 705 are written in the 2014 NEC, the installation should be allowed. That seems to be the intent of the cable limiter exception and the distance limits in 705. Chapter 7 modifies Chapter 2. This is your best argument IMO.

(However, get ready to no longer be able to make that argument when the 2023 NEC applies.)

 

[MTPR220]

great point, 705.31 refers to the conductors as "electric power production source conductors connected to the supply side of the service disconnecting means" not electric power production "service conductors/service entrance conductors", which may be a great starting point. thanks for the heads up on 2023 as well

 

[pv_n00b]

705.31 overrides 230 in the 2017 NEC and can result in long runs of unprotected service entrance conductor inside buildings. The conductors basically have unlimited length once the current limiters are installed. This was the crux of the battle in the 2023 NEC that was resolved by putting those conductors under 230.

 

[MTPR220]

So I have not seen the 2023 code edition yet, but would there be an alternative installation method that may comply with article 230 without having to trench under the building or through a brick/concrete chase etc. to reach the supply side interconnection point?

 

[jaggedben]

So I have not seen the 2023 code edition yet, but would there be an alternative installation method that may comply with article 230 without having to trench under the building or through a brick/concrete chase etc. to reach the supply side interconnection point?

Probably only if you can put the main PV disconnect right at the service equipment. The relevant parts of article 230 did not change AFAIK. It's up to the AHJ to determine how near is 'nearest the point of entrance.'

 

[pv_n00b]

The removal of the provision for the use of cable limiters also removed all the conductor length allowances. It's now treated like any other unprotected service entrance conductor, which means the length between building penetration and disconnect is in the eyes of the AHJ.