August 2016 utility service requirements manual, supply side connection, GEC options

[peterlarsen.suntec]

We have a new service requirements manual from our utility here in SC. It's great news, now we an all get on the same page, installers, utility, and inspectors!

We have options to land the GEC either in the meter or at the "first point of accessible disconnect".

In reference to net metered solar interconnections, the manual offers 3 methods to connect. There is the typical method of back feeding into a MDP, and two options for supply side connections. One option includes a trough, the other is a supply side meter connection. Please see below.

We are using option (A). The question is, when using the UL listed accessory double lug kit on the load side of the POC, where would be the best place to land the GEC?

Which one is easier to change if required by an inspector with a differing opinion of the best selection?

We have options...

According to Duke as shown in figure 14A we can bond at the "in service disconnecting means". This means we can land our #6 bare GEC in the PV meter or the PV disconnect.

Approach 1:
We can land the neutral in the disco at an isolated neutral terminal, we can land an auxiliary GEC on a ground bar. Then we can treat the PV disconnect as a service disconnect or a feeder disconnect by installing the bonding screw or not.

Approach 2:
We can land an auxiliary GEC in the PV meter, then run separate neutral and EGC to the disco landing the neutral and EGC as described above. Again, installing the bonding jumper screw will determine weather it is considered a service disconnect or feeder disconnect.

Since the PV meter is technically "not accessible" because you must cut the tab to remove it, it may not be viewed as the "disconnecting means" by an inspector.

I would be inclined to pick option 1. What do you guys think?


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[iwire]

Bumping this to the front page.

 

[pv_n00b]

The answer depends on if you, and the AHJ, consider the supply side PV interconnection to be a service entrance or a feeder tap. If it's a feeder tap then you just run an EGC. If it's a service entrance then you can follow one of the options they have given for a service entrance.

 

[peterlarsen.suntec]

The answer depends on if you, and the AHJ, consider the supply side PV interconnection to be a service entrance or a feeder tap. If it's a feeder tap then you just run an EGC. If it's a service entrance then you can follow one of the options they have given for a service entrance.

Here lies the challenge. The inspectors are not willing to meet or discuss each project. Different inspectors in the same counties have different opinions as to how the connections should be treated. We don't know what they will say until the inspection.
In any case, we have no place to connect an EGC in the existing meter socket. Is landing an auxiliary GEC in the PV disco on a ground bus and neutral on an insulated neutral bus with the ground screw uninstalled an acceptable method of wiring a feeder disconnect? Does installing the bonding jumper make it an acceptable service disconnect?


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[electrofelon]

The answer depends on if you, and the AHJ, consider the supply side PV interconnection to be a service entrance or a feeder tap. If it's a feeder tap then you just run an EGC. If it's a service entrance then you can follow one of the options they have given for a service entrance.

I understand the point you are trying to get across, but I have issue with use of the term "service entrance" as it is a vague undefined word. Secondly, it is definitely not a feeder tap.

 

[jaggedben]

Here lies the challenge. The inspectors are not willing to meet or discuss each project.

Try to get each AHJ to commit to whether the disco is a service disconnect, or not, or they don't care.

Different inspectors in the same counties have different opinions as to how the connections should be treated. We don't know what they will say until the inspection.

Welcome to the world of PV supply side connections. Sorry.

In any case, we have no place to connect an EGC in the existing meter socket.

Maybe you could install a ground bar? Depends on the socket, of course...

Is landing an auxiliary GEC in the PV disco on a ground bus and neutral on an insulated neutral bus with the ground screw uninstalled an acceptable method of wiring a feeder disconnect? Does installing the bonding jumper make it an acceptable service disconnect?

I don't see that as complying with running the EGC with its circuit conductors. (I also don't know what you mean by 'auxilliary). To my mind, however, you can run a GEC from the disco directly to the grounding electrode, and bond neutral to ground in the PV disco, IF you can get the AHJ to agree that it's a service disconnect.

My strategy on smaller systems (up to 60A disco) has been to run both neutral and ground to the disconnect and bond them there. I size my 'ground' adequately for a GEC (i.e. #8 minimum) and run it back through the point of my supply side connection to wherever the existing GEC is connected. If the AHJ thinks sees it a service disconnect, I'm all set. If the AHJ objects to the neutral-ground bond as allowing objectionable current, or because PV is not a service, I remove the green screw and call the ground an EGC. So far this has worked for me, but granted I've never had to install a PV production meter on the line side of the disco. Actually I don't think I've yet been asked to remove the green screw, although I once was asked to explain my install and made the offer.

 

[pv_n00b]

I understand the point you are trying to get across, but I have issue with use of the term "service entrance" as it is a vague undefined word. Secondly, it is definitely not a feeder tap.

And this is where all the arguments start on this subject, but I'm not going to go there.

 

[pv_n00b]

Here lies the challenge. The inspectors are not willing to meet or discuss each project. Different inspectors in the same counties have different opinions as to how the connections should be treated. We don't know what they will say until the inspection.
In any case, we have no place to connect an EGC in the existing meter socket. Is landing an auxiliary GEC in the PV disco on a ground bus and neutral on an insulated neutral bus with the ground screw uninstalled an acceptable method of wiring a feeder disconnect? Does installing the bonding jumper make it an acceptable service disconnect?

I don't know how to address that one. If they won't tell you until it's installed and inspected, then the particular inspector decides which they want to see, that's a bunch of hooey. Technically if different inspectors are applying different requirements in the same jurisdiction you should be running that up the chain of command, it's not legal and some deep pocket developer can sue. The AHJ management usually will not back up this kind of variability from inspectors.

 

[tritium]

My strategy on smaller systems (up to 60A disco) has been to run both neutral and ground to the disconnect and bond them there. I size my 'ground' adequately for a GEC (i.e. #8 minimum) and run it back through the point of my supply side connection to wherever the existing GEC is connected. If the AHJ thinks it's a service disconnect, I'm all set. If the AHJ objects to the neutral-ground bond as allowing objectionable current, or because PV is not a service, I remove the green screw and call the ground an EGC. So far this has worked for me, but granted I've never had to install a PV production meter on the line side of the disco. Actually I don't think I've yet been asked to remove the green screw, although I once was asked to explain my install and made the offer.

Ditto this. It's a simple enough way to satisfy whoever shows up for the given inspection. We've actually had different inspectors in the same jurisdiction have differing opinions on this one. Though we've had issues with Duke on the point of equipment order, we've never had an issue with the AHJs in Duke's territory going this route.

By the way, SCE&G's engineering department has a very strong opinion on this.

 

[peterlarsen.suntec]

There is rumor that the AHJ is adopting the service entrance view and expecting the bonding jumper in the disco on supply side connections. I heard an inspection failed because there was no bonding jumper in the disco and that a GEC will be required in the disconnect. There will be a meeting of the AHJ to get inspectors on board.

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[ggunn]

By the way, SCE&G's engineering department has a very strong opinion on this.

And that's a good thing when they spell out exactly what they want to see. Personally, I do not care which way the AHJ leans on the issue as long as they are clear about the way they want it done so I can comply and pass my inspection.

 

[electrofelon]

And this is where all the arguments start on this subject, but I'm not going to go there.

I dont really think there is any debate about it is there? A supply side connections is not a feeder tap, and it is not a service or "service entrance" (whatever that is).

 

[peterlarsen.suntec]

Thanks to all! I am learning, at least the POCOs and AHJs in this area are making it clear about how they want it done. Now hopefully we can get our designers on board.

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[mpd]

the PV supply side disconnect is not a service disconnect, no GEC is not required to be connected to the PV supply side disconnect.

 

[jaggedben]

Well, that's an opinion.

 

[peterlarsen.suntec]

the PV supply side disconnect is not a service disconnect, no GEC is not required to be connected to the PV supply side disconnect.

Ok,The grounded current carrying conductor and other current carrying conductors(#10) land in the utility meter socket on the supply side using listed double lugs accessories.The EGC(#6) lands in the meter socket and is split bolted to the GEC. Then the EGC and CCC are landed in the PV meter socket.The GCC is run through the PV meter socket and disconnect and lands in the inverter. The EGC is connected in the disco to a ground lug and ground bushings and lands in the inverter, the CCCs are landed in the 30 amp fused disconnect and then the inverter. So this connection is treated as a feeder, ground and neutral separate from the bonding jumper in the utility meter. The 30 amp disco is acceptable because it is not considered a service disconnect.
This install passed yesterday. Just seems sketchy to me. It just seems bass ackwards. But then I'm not the qualified person on these installs.

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[jaggedben]

Ok,The grounded current carrying conductor and other current carrying conductors(#10) land in the utility meter socket on the supply side using listed double lugs accessories.The EGC(#6) lands in the meter socket and is split bolted to the GEC. Then the EGC and CCC are landed in the PV meter socket.The GCC is run through the PV meter socket and disconnect and lands in the inverter. The EGC is connected in the disco to a ground lug and ground bushings and lands in the inverter, the CCCs are landed in the 30 amp fused disconnect and then the inverter. So this connection is treated as a feeder, ground and neutral separate from the bonding jumper in the utility meter. The 30 amp disco is acceptable because it is not considered a service disconnect.
This install passed yesterday. Just seems sketchy to me. It just seems bass ackwards. But then I'm not the qualified person on these installs.

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I know, right? It's not like the utility fault current is different because this is an interactive inverter output. Is the disco even suitable for use as service equipment?

I'm not trying to start another argument about what the code technically requires. I'm just sayin' I agree with you.

 

[peterlarsen.suntec]

I think not, but a passed inspection is a passed inspection. I have a saying, not that anyone listens, "just because an inspector passes it doesn't make it right." I once saw a neutral connected to a 2 pole GFI line voltage terminals on a hot tub panel. Of course, the control board was fried. The response from the Electrician was "it passed inspection".

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[gadfly56]

Here lies the challenge. The inspectors are not willing to meet or discuss each project. Different inspectors in the same counties have different opinions as to how the connections should be treated. We don't know what they will say until the inspection.
In any case, we have no place to connect an EGC in the existing meter socket. Is landing an auxiliary GEC in the PV disco on a ground bus and neutral on an insulated neutral bus with the ground screw uninstalled an acceptable method of wiring a feeder disconnect? Does installing the bonding jumper make it an acceptable service disconnect?


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OK, I don't understand this. In these parts you submit a drawing with your permit application showing what you intend to do. The electrical subcode official signs off on it and that's what you install. Never mind problem solved, there just ain't a problem, or if there is it's all ironed out before the permit is issued.

 

[peterlarsen.suntec]

Yes some counties do this. I believe we submit a one line. So the matter of the GEC is not defined.

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