690.47 connecting array to building GES

[electrofelon]

Say I have a house with a roof mounted array. The house electrical is served by a remote meter/main on a pedestal. The Array does NOT interconnect at the house, instead the AC inverter output(s) go to the meter/main on pedestal and the interconnection is there. Do I need to make a connection between the array EGC to the GES AT the house, or is the connection at the meter main which serves the house and ultimately connects to the GES at the house acceptable? I say the latter is acceptable.

 

[wwhitney]

For reference, the start of 2026 NEC First Draft 690.47 is below. So I would say the question is whether the GES referred to in the second paragraph is necessarily the GES referred to in the first paragraph. And then if it is, is the connection via the feeder to the house sufficient to comply with 690.47?

Cheers, Wayne

690.47 Grounding Electrode System.
(A) Buildings or Structures Supporting PV Systems.
Buildings or structures supporting PV systems shall use a grounding electrode system installed in accordance with Article 250, Part III.

PV array equipment grounding conductors shall be connected to a grounding electrode system in accordance with Article 250, Part VII, in addition to any other equipment grounding conductor requirements in 690.43(C). . . .

 

[jaggedben]

We had a discussion about this a while back that I can't find. Anyway I'm came to the conclusion that the code language does not strictly require a connection at the same structure and if you have a good reason not to connect things there then it's worth arguing for the strict reading of the code.

A good reason not to connect them at the same structure might be if the GES were bonded to a neutral at the house, since in that case the array GEC/EGC loop back to wherever it's interconnected might create a parallel return path for neutral current.

In your case, if I'm reading correctly that you have a PV circuit and a load feeder to the house but all neutral bonding is at the pedastal, I don't know that it matters either way.

 

[electrofelon]

I should have mentioned, but this would be the 2017 code. It appears the wording is mostly the same however the latest version says "shall use" which is interesting.

Yes ben, in my case the house is served with four wire so there wouldn't be a parallel path.

Another part of this that I got thinking about and is kind of interesting: so say we do want to make a connection at the house. 690.47 refers you to part VII of article 250. So it seems that all we would need is even an empty conduit meeting 250.118 between a PV system conductor box and a house conductor box and that would meet the requirement.

 

[ggunn]

I should have mentioned, but this would be the 2017 code. It appears the wording is mostly the same however the latest version says "shall use" which is interesting.

Yes ben, in my case the house is served with four wire so there wouldn't be a parallel path.

Another part of this that I got thinking about and is kind of interesting: so say we do want to make a connection at the house. 690.47 refers you to part VII of article 250. So it seems that all we would need is even an empty conduit meeting 250.118 between a PV system conductor box and a house conductor box and that would meet the requirement.

Is there a disconnect at the pole? If you connected at the house would your PV interconnection line or load side?

 

[electrofelon]

Is there a disconnect at the pole? If you connected at the house would your PV interconnection line or load side?

Not sure what you mean by "pole". The house is fed by a feeder so obviously it would be a load side if I connected at the house. But I'm not planning to connect to the house, going back to the meter main and connecting load side there.

 

[ggunn]

Not sure what you mean by "pole". The house is fed by a feeder so obviously it would be a load side if I connected at the house. But I'm not planning to connect to the house, going back to the meter main and connecting load side there.

Pole or pedestal with OCPD, OK, but you'll probably need to add a main breaker to the house panel if it is MLO. But why would you want to trench to the pedestal if the MDP and the solar array are both on the same building? You can tap either end of that feeder.

 

[electrofelon]

. But why would you want to trench to the pedestal if the MDP and the solar array are both on the same building?

......Because I had the foresight to put in a pipe from the house back to the pedestal when we brought the service in! . Also where the pedestal is there's going to be nine more panels in a ground Mount at the pedestal. Of course there were multiple ways to skin this cat but I decided to put the enphase combiner at the pedestal and interconnect there.