EGC required in all non metallic conduits?

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
Well then we have the change of the definition of structure where the words "other than equipment" were added.
Sure, you'd have to figure out the dividing line between "equipment only" and a "structure". Not sure if it's reasonable to say that the entire ground mount supporting apparatus is equipment.

The answer also would depend on whetjer or not AC or DC were run to the array.
How so? I would say PV output conductors meet the definition of feeder.

Cheers, Wayne
 

Jesse7623

Senior Member
Location
eastern Mass
I am certainly no expert on UL 1703, but I think that is more about all the bonding between the racking structure components and modules. Even if it does cover earthing, they don't have any authority to designate grounding electrodes or when earthing is required. One final note, it depends on the code cycle whether a grounding electrode is even required at an array so that is another thing to throw in the mix.
well, the UL listing is what qualifies a piece of metal that doesn't meet the measurements, as an electrode.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
250.52 (6) permits 'Other Listed Electrodes' besides those described in the rest of 250.52, and the section on rods specifically calls out that they do not need to meet the NEC dimensions if listed. So I gather there is a UL standard for electrodes somewhere? Not that I see why it matters here.

I think the wires from the arrays to the ground ring are not GECs but may qualify as bonding jumpers for the grounding electrode system. Also presumably there is a bona fide GEC between the ground ring and the whatever the inverters ground terminals are bonded to, which is for now serving the function of an EGC for inverter ground fault detection. It's all kinda moot, though, if we conclude that whatever we call 'em they don't follow the rules for EGCs.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Sure, you'd have to figure out the dividing line between "equipment only" and a "structure". Not sure if it's reasonable to say that the entire ground mount supporting apparatus is equipment.


How so? I would say PV output conductors meet the definition of feeder.

Cheers, Wayne
Let's not rehash this. It's not ultimately relevant to whether a separate EGC is needed.
 

Jesse7623

Senior Member
Location
eastern Mass
250.52 (6) permits 'Other Listed Electrodes' besides those described in the rest of 250.52, and the section on rods specifically calls out that they do not need to meet the NEC dimensions if listed. So I gather there is a UL standard for electrodes somewhere? Not that I see why it matters here.

I think the wires from the arrays to the ground ring are not GECs but may qualify as bonding jumpers for the grounding electrode system. Also presumably there is a bona fide GEC between the ground ring and the whatever the inverters ground terminals are bonded to, which is for now serving the function of an EGC for inverter ground fault detection. It's all kinda moot, though, if we conclude that whatever we call 'em they don't follow the rules for EGCs.
Maybe they fall under supplemental/supplementary grounds. But yes, definitely not EGCs.
 
250.52 (6) permits 'Other Listed Electrodes' besides those described in the rest of 250.52, and the section on rods specifically calls out that they do not need to meet the NEC dimensions if listed. So I gather there is a UL standard for electrodes somewhere? Not that I see why it matters here.
Ok interesting, I hadn't noticed that. Also (8) may apply, bit it is quite vague and doesn't say who decides.
 

pv_n00b

Senior Member
Location
CA, USA
You're right. I was using the wrong numbers while thinking of IEEE 1547 and meant UL 1741 and UL 2703
I thought that might be the case. All these numbers get mixed up in my head. Anyway, UL 2703 does not deal with grounding electrodes, just that the racking can act as an EGC in the array as a replacement for running a wire EGC between modules and the racking. In large ground mounts, a UL 2703 listed rack will usually be mounted on an unlisted support system that includes the foundation. For the foundation to be considered a grounding electrode in the NEC it has to meet the UFER requirements. If it does not meet the UFER requirements the foundation steel can still be tied into the EGC system but it's not an official grounding electrode. But the more ground contact the better I say.
 

pv_n00b

Senior Member
Location
CA, USA
UL, CSA etc., are literally the entities that list/approve parts/equipment for the NEC. "UL approved"... I didn't know this was unknown.
Kind of... NRTLs test equipment that is submitted to them by the manufacturer to the relevant UL Standard and if it passes then the equipment gets put on a list and gets a mark. The NEC and AHJs can then refer to the list and require the mark if desired. If you get into it there is a lot of back and forth between UL people and people on the NEC code making side over which is more important. Mostly good-natured ribbing. UL 467 covers grounding electrodes, but grounding electrodes are not required by the NEC to be listed if they meet the design requirements in the NEC.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I guess I missed the original hashing, do you have a pointer?

Cheers, Wayne
You were right in the thick of it.

 
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