Additional Auxiliary Electrodes

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PURE

Member
Location
columbus, ohio
2014 NEC 690.47 (D) States a Grounding electrode shall be installed close as practicable to the location of a roof mounted PV array. (residential roof mount)

If the array has a EGC coming up from the inverter to the array, and a GEC from the Inverter to the existing AC Ground rod. Why would i want to run another electrode conductor from my rails to a new DC ground rod on the other side of the house? This seems like a bad idea, and now creates a second path to ground for the entire service, and that path is up and over the house. Please don't tell me its Lightning protection, as that acorn and the new ground rod are not getting that job done either.
Currently here in Ohio, inspectors are looking for a #6 Bare off the array directly to the AC GEC or ROD, in addition to the EGC already ran with the array to inverter lines.
Are they getting this confused with Bonding all the rails? FYI, simple system, 12 panels, Solar Edge Opt, Solar edge inv. Iron ridge flashing feet on asphalt shingles, wood frame.
 
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Carultch

Senior Member
Location
Massachusetts
PURE said:
2014 NEC 690.47 (D) States a Grounding electrode shall be installed close as practicable to the location of a roof mounted PV array. (residential roof mount)

If the array has a EGC coming up from the inverter to the array, and a GEC from the Inverter to the existing AC Ground rod. Why would i want to run another electrode conductor from my rails to a new DC ground rod on the other side of the house? This seems like a bad idea, and now creates a second path to ground for the entire service, and that path is up and over the house. Please don't tell me its Lightning protection, as that acorn and the new ground rod are not getting that job done either.
Currently here in Ohio, inspectors are looking for a #6 Bare off the array directly to the AC GEC or ROD, in addition to the EGC already ran with the array to inverter lines.
Are they getting this confused with Bonding all the rails? FYI, simple system, 12 panels, Solar Edge Opt, Solar edge inv. Iron ridge flashing feet on asphalt shingles, wood frame.
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Put it in to satisfy the AHJ, and then disconnect it after you pass your inspection, if is counterproductive to safety.

This part of the NEC is known to be problematic. Mike Holt calls it 690.47(D)anger.
https://www.youtube.com/watch?v=YuDqXFvRv94
 
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pv_n00b

Senior Member
Location
CA, USA
This is the yo-yo section, came in in 2008, went away in 2011, came back in 2014 because a bunch of people said it was removed because of an editing error. I've been against this from the beginning when the people behind it kept calling out lightening as one of the reasons for it.

Basically if the AHJ wants it you have to give it to them. I personally don't think it is a danger on a building where the electrode will be close to the grounding electrode system anyway, just useless extra work. It can be dangerous when electrodes are isolated with significant distance between them due to ground voltage rise.

In 2017 it's not going away but it has changed with the liberal addition of the phrase, "shall be permitted to be installed," in place of "shall be installed," which is much improved. Pretty much everyone will ignore it then.
 
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jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
pv_n00b said:
Find out what they were doing under the 2008 NEC, if they were requiring it then they will probably require it when 2014 hits.
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Well, I don't want to remind anyone of anything they might have forgotten. ;)

I'm familiar with most of the closer in AHJs, but there's a bunch we're working in now that we weren't 2.5 years ago. Also we work in about two dozen AHJs so it's not a short project. I'll probably just have to take it as it comes.
 
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c_picard

Senior Member
Location
USA
pv_n00b said:
Can't tell the players without a score card. Maybe you should make a set of AHJ player cards like baseball cards. :)
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No kidding, at last count I've got 7,313 separate AHJs, including base commanders and HOAs. Grounding requirements are literally all over the map.
 
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