Another thing is each time a metal frame panel mount touches the ground its basically doing the ground path thing there anyways so were back to might as well ground the suckers.
Panel grounding to rod at location (not to main breaker due to distance)
- Thread starter Gurusi
- Start date
Gavin Stone
Solar Addict
Exactly. It’s code for a reason. If you wanted to achieve zero grounding you’d use a wooden array. I have wooden array with panels built as a roof. And when I started up my older lv6548 system for testing, the panels shocked me. And not just a little shock either. My arm twitched for a while afterwards. It had ac on the PV line. And that was before people were mentioning or aware of it.
I’m not necessarily saying that’s the motivation for grounding the array. I’m saying you can achieve zero grounding with wooden arrays. But that’s not necessary. Ground the arrays and use surge protection.
Adam De Lay
Solar Wizard
Yep, I saw it. I knew I was the "internet guy", which is fine.
He and I actually had a lot of discussion in the comments of my video. He actually said that I should mount the panels on metal roofing, even just put the metal roofing on the wooden rack and then ground the metal as a whole. Not sure how that's any different from grounding with a ground wire? He also mentioned that he doesn't ground any of his panels directly, but he does only mount them on metal roofing.
There's been lots of discussion on the forums about the cheap AIO inverters leaking AC on the metal frames of the panels. How it gets there, got me. I don't understand much of it, but smarter people than me have explained it.
I actually had 1 array ungrounded for some testing, my son and nephew were swimming in the pool and while they were wet, ended up touching the array and got a good zap. Ultimately it boils down to safety. Everyone can tell me "don't ground the panels because of ..." but if people are getting shocked due to some voltage leaking from the inverters, I'm gonna ground them...
Zwy
Solar Wizard
I've watched that guy's videos, he sure is whacked.
Zwy
Solar Wizard
An auxillary rod is allowed. However, those in the know say NO to auxillary rod.
An EGC is required to be ran from array to system grounding.
OP will need to run an EGC to system grounding. Everything metal connected to system requires an EGC.
One of the things I find curious is the path for current flow not only to the panel frame of AC voltage but how it transmits through the person being shocked to ground and than back to the AIO. The recent Thread where a person is experiencing a hot skin affect on his solar trailer is particularly confusing because there is no actual ground.
Adam De Lay
Solar Wizard
Doesn't the person become the ground connection in a "hot skin" scenario? I can't remember where I saw it, but I thought I read where someone's dog ended up dying due to "hot skin" on an RV.
Zwy
Solar Wizard
Parallel path.
Current will flow on a parallel path. The person's body becomes the parallel path.
When the hot skin is from a miswired shore power setup and trailer wiring there is the shore power ground as current path. However in this fellows case he is not connected to shore power. No earth ground at all even if he wired his AIO using the trailer frame as ground.
Zwy
Solar Wizard
I experienced it 20 years ago building a work trailer that would plug into customer's power.
I had an old fuse box laying around, used it mainly for a switch. I bonded N and G together in the box. Always noticed dogs would come to pee on the tires and run off yelping. Even touching their nose to metal would cause it. If I returned to the site at a later date, the dog would run away as fast as it could when it saw me pull in.
One day on some damp ground, I felt it. The tingle and knew that was why the dogs would take off. It was the N-G bond in the trailer.
Last edited:
Zwy
Solar Wizard
Provide a link because I don't know all the details but I can assure you it is a parallel path or N-G are not bonded under inverter power.
Adam De Lay
Solar Wizard
Zwy
Solar Wizard
I quit watching after 3 minutes. Couldn't take it. I'll leave it at that.
Zwy
Solar Wizard
Always thought about adding a switch.......
Zapper77
Renaissance Man
- Joined
- Jul 23, 2022
- Messages
- 2,321
My inspector was good with my "galvanized" ground screws. He didn't ask how long they were and I didn't tell him they were only 82". He also didn't require that the PV array be grounded/bonded to the primary structure. I replied with...sounds good.
"(2) Metal In-ground Support Structure(s). One or more metal in-ground support structure(s) in direct contact with the earth vertically for 3.0 m (10 ft) or more, with or without concrete encasement. If multiple metal in-ground support structures are present at a building or a structure, it shall be permissible to bond only one into the grounding electrode system.
Informational Note: Metal in-ground support structures include, but are not limited to, pilings, casings, and other structural metal."
Zwy
Solar Wizard
It doesn't matter if the array is metal or not, if metal it is just considered an auxiliary grounding electrode. It is allowed but not necessary.
However, any metal on a system is required to have an EGC to detect and clear ground faults. The earth path is not considered a conductor and low resistance path. An EGC is required to be run with any current carrying conductors.
Zapper77
Renaissance Man
- Joined
- Jul 23, 2022
- Messages
- 2,321
I'm only referring to NEC 250.52 Allowing structure to count as grounding rod. In my specific build the panels are bonded to structure and said structure is bonded to "approved" grounding (per my local inspector.)
Note: not everyone on the globe that we call earth follows the American National Electric Code.
As for bonding the array to my main structure....its technically achieved through a combination of 6awg (exposed) and 10awg (conduit) that travels back to the main panel.
That's not even including the 2-6 awg parallel grounds from the inverter to the main panel.
Zwy
Solar Wizard
The structure is just an auxiliary grounding rod according to NEC.
I think some believe an EGC from array to main system grounding is not needed as there is a ground rod at the array. Any grounding at the array is just an auxiliary ground. It is required to connect it to main grounding system.
When it comes to grounding, it would be wise to follow it. I think some like to interpret certain sections or choose a menu of only certain things. When it comes to grounding, it is quite specific.
As long as there is a grounding electrode at the main panel with N-G bonded and an EGC that runs with current carrying conductors from the PV array, then it is according to NEC grounding requirements. Anything else is fluff and not needed or required, in other words, money down the toilet.
Many believe they can use either a grounding electrode or the array structure as the grounding for the array. This is incorrect, any grounding at the array is an auxiliary ground. An EGC needs to be run from array/auxiliary ground to main grounding system which is usually at the inverter/electrical panel installation. An auxiliary ground is not needed, nor is it not permitted. It just "exists".
What NEC should do is to not allow an auxiliary grounding electrode, it would eliminate confusion. A metal PV array structure is allowed but not an auxiliary grounding electrode.
PunchySunshine
Solar Enthusiast
Zwy
Solar Wizard
Watched that last night.
Similar threads
