supply side PV connection

mpd

Senior Member
Is SEU cable permitted for a supply side connection and the bond screw installed at the supply side disconnect and then 4 wire to the PV equipment or must the supply side PV conductors be 4 wire with an insulated neutral & EGC to the PV disconnect and no bond screw installed, or are both methods compliant?
 

jaggedben

Senior Member
Is SEU cable permitted for a supply side connection and the bond screw installed at the supply side disconnect and then 4 wire to the PV equipment or must the supply side PV conductors be 4 wire with an insulated neutral & EGC to the PV disconnect and no bond screw installed, or are both methods compliant?
Very debatable. See here for the most recent debate on this forum.

Bottomline: ask your AHJ before you do anything you can't afford to change.
 

Smart $

Esteemed Member
Location
Ohio
Very debatable. See here for the most recent debate on this forum.

Bottomline: ask your AHJ before you do anything you can't afford to change.
Here it appears we are debating whether a 3-wire service entrance conductor and GC/EGC bonding jumper can be installed, or should it be a 3-wire with ground and GC remain isolated from EGC.

I am agreeable to either, but I prefer the former. What say you?
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Here it appears we are debating whether a 3-wire service entrance conductor and GC/EGC bonding jumper can be installed, or should it be a 3-wire with ground and GC remain isolated from EGC.

I am agreeable to either, but I prefer the former. What say you?
I say that there are there are three possibilities: the AHJ may stipulate one way, the AHJ may stipulate the other way, or the AHJ may not stipulate. Find out which before proceeding.
 

Smart $

Esteemed Member
Location
Ohio
I say that there are there are three possibilities: the AHJ may stipulate one way, the AHJ may stipulate the other way, or the AHJ may not stipulate. Find out which before proceeding.
I'm amenable to that premise! :happyyes:
 

mpd

Senior Member
I don't see where either method would be a violation, the NEC has determined these supply side conductors as feeders, in a recent technical opinion I received from NFPA in reference to grounding, NFPA responded that NEC 690.43 (A) applies and the only articles in 250 that can be enforced is 250.134 or 250.136 (A), I don't see where either of these code sections would prohibit SEU cable for a typical residential supply side connection, article 250.134 allows 250.142 that permits the grounded conductor to be used for grounding enclosures on the supply side and 230.40 exception #5 would also seem to permit this.
 

mpd

Senior Member
That is not correct, there must be a mix up. They are service entrance conductors. Are you talking about the conductors between the tap point and the PV disconnect?

yes the supply side conductors per 705.12 (A) per NFPA are feeder conductors
 

Smart $

Esteemed Member
Location
Ohio
yes the supply side conductors per 705.12 (A) per NFPA are feeder conductors
Was that a formal interpretation from the NFPA? ...or an "informal" interpretation by the/an on-staff electrical engineer?

If the former, that'd contradict in-the-Code text, including a couple if not several definitions. :blink:
 

mpd

Senior Member
Was that a formal interpretation from the NFPA? ...or an "informal" interpretation by the/an on-staff electrical engineer?

If the former, that'd contradict in-the-Code text, including a couple if not several definitions. :blink:
it was informal in writing, NFPA said in there response that none of article 230 applies unless referred to by art. 705, and I also talked to John Wiles about this and he also said NFPA now considers these feeder conductors.
 

Smart $

Esteemed Member
Location
Ohio
it was informal in writing, NFPA said in there response that none of article 230 applies unless referred to by art. 705, and I also talked to John Wiles about this and he also said NFPA now considers these feeder conductors.
Well I haven't had time to process that, but it sounds like someone got that all mucked up. There's no way, barring radical changes to definitions and sections, that conductors on the POCO side of a supply-side disconnect can be considered feeders. If we thought the debateability was extreme in the past, I can hardly wait to see what the 2017 edition brings if what you are saying is the case.

:blink::happyyes::happysad::lol::rant::eek:hmy::?
 

c_picard

Senior Member
Location
USA
it was informal in writing, NFPA said in there response that none of article 230 applies unless referred to by art. 705, and I also talked to John Wiles about this and he also said NFPA now considers these feeder conductors.
Wiles and Co. are wrong on this one, and the NFPA botched the response. Much to my dismay, there may continue to be a debate on what they are, but they sure as heck ain't feeders
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
So if they aren't service conductors, and they aren't feeders, they must be branch circuit conductors. The line side tap is the outlet. :)

Cheers, Wayne
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
While it sounds crazy, it is actually the best match I am aware of among the 2011 Article 100 definitions. I thought 2017 was going to clear this up, or is that wishful thinking?

Cheers, Wayne
 

mpd

Senior Member
Wiles and Co. are wrong on this one, and the NFPA botched the response. Much to my dismay, there may continue to be a debate on what they are, but they sure as heck ain't feeders
the new section in the 2014 NEC 705.31 calls those conductors electric power production source conductors now, I agree it does not make much sense that PV conductors connected to the supply side become something different at that connection
 

mpd

Senior Member
I suspect the OP misheard, or the guy he heard it from misheard, and they were talking about the conductors between the PV disconnect and a combiner panelboard.....
the question that I submitted & response from NFPA was in reference to a supply side connection and the conductors to the supply side PV disconnect, and it was in writing from NFPA
 

pv_n00b

Senior Member
Location
CA, USA
I saw this angle coming when in 2014 705.31 was added to limit the distance from the POCC to the first OCPD to 10ft. This brought it in line with 240.21(B)(1) for taps 10ft or less in length where the size of the conductor has no relation to the supply. It's not clear in the code if 705.31 is limiting the conductor length to 10ft or just the straight line distance from the tap to the OCPD and the conductor can be longer. In the substantiation for the proposal that created the new section the proposer wrote in part, "This proposal would require short-circuit protection (cable limiters) whenever the length of unprotected cable exceeded 3m (10 ft)," which indicates that the intended interpretation is a 10ft conductor length.

Actually the proposal in my opinion is incorrect in that it assumes the conductors are feeders that should have OCPD and not service entrance conductors that do not need OCPD. If the conductors were considered service entrance conductors we would have much more flexibility.

No one should be looking at this as a good thing. Before 705.31 there was no limit to the length of the conductor between the POCC and the OCPD and I had several projects where a 10ft limit would have been a problem. Giving up the ability to install a supply side interconnection as a service entrance is a net loss for us.
 
Top