Panel grounding to rod at location (not to main breaker due to distance)

[Gurusi]

Hey, I have just built my ground array (lumber) with 32 panels approx 300ft from my property. The setup runs 6awg PV wire from the panels to my inverters at my home (off grid setup).

I had planned to ground my panels with grounding rods at the location for simplicity due to distance to my home, cost and the fact that I have the land and space; however after reading Filterguys resource at appears that grounding to the main breaker is preferential.

To run to the main breaker ground would require buying a load more 6awg earth wire, trenching etc back to the home.

Has anyone else grounded panels only at the source? and could I take this route of will it affect safety for the future. I believe having a rod/s at the source may make it more attractive to lightening?

Just to confirm my actual earth bond setup for the system is via the main breaker, the above is regard the panel frames.

 

[Mattb4]

I do not see that you need to ground your panel frames. But if you want to I also think a ground rod and wire at location would do the trick. Do not ground your negative PV wire. Yes lightning can be attracted if the panels are grounded unless a more attractive ground is locally available.

 

[Gurusi]

I do not see that you need to ground your panel frames. But if you want to I also think a ground rod and wire at location would do the trick. Do not ground your negative PV wire. Yes lightning can be attracted if the panels are grounded unless a more attractive ground is locally available.

Thanks for putting my mind at rest. Yes my intention is the frame only. I want it to be safe and as to code as possible but not at additional unnecessary? Expense running cable back to my home

 

[Mattb4]

If your location requires an electrical code inspection than of course you would need to follow whatever nonsense the inspector demands.

 

[Mattb4]

Posting a follow up due to some testing from my new high voltage PowMr AIO. It does put half the AC voltage on the PV lines and when testing between panel frames that are not grounded to ones that are I found 62.5vAC (current so low it does not light up a small wattage bulb but the DMM sees it) when measuring.

So I would recommend that all frames be electrically connected to prevent possibility of shock.

 

[Adam De Lay]

Seems like lots of AIO inverters have this issue...

 

[Mattb4]

Seems like lots of AIO inverters have this issue...

Interesting enough I do not have the issue (just went and tested my #2 PV array) that is on my lower PV voltage EAsun AIO.

The fellow in the video does a good job of walking through it all. His method of testing for electricity using his finger is not one I would recommend.

 

[Adam De Lay]

Interesting enough I do not have the issue (just went and tested my #2 PV array) that is on my lower PV voltage EAsun AIO.

The fellow in the video does a good job of walking through it all. His method of testing for electricity using his finger is not one I would recommend.

Dunno, with that finger licking test...kinda seems like an idiot to me...

 

[Gurusi]

I plan to run 6awg cable to the conductor rod/plate. Can anyone advise on what awg to use for bonding when running from panel ground lug to lug ?

 

[zanydroid]

Code requires use #6 for independent & exposed runs. For my rooftop array I bonded all rails with #6 and transitioned to #10 once the EGC went into a regularly protected wiring method (in first junction box on the roof the #6 was spliced down to #10 for 30A microinverter branch circuit and 15A ISC solar panels).

I’m not sure what level of physical protection of the EGC would allow you to downsize. Probably if protected by the framing you can go down to #10 for typical PV and inverter generated fault currents. But I don’t have a code reference.

 

[Gurusi]

Thanks for the info. For ease I will stick to 6 gauge throughout

 

[JoeHam]

I believe NEC code compliance requires running a ground wire back to the main house ground.

 

[Mattb4]

It seems to read to me that a local grounding rod is within code. https://www.electricallicenserenewa...ation-Courses/NEC-Content.php?sectionID=384.0

N (B) Additional Auxiliary Electrodes for Array Grounding. Grounding electrodes shall be permitted to be installed in accordance with 250.52 and 250.54 at the location of ground and roof-mounted PV arrays. The electrodes shall be permitted to be connected directly to the array frame(s) or structure. The grounding electrode conductor shall be sized according to 250.66. The structure of a ground-mounted PV array shall be permitted to be considered a grounding electrode if it meets the requirements of 250.52. Roof mounted PV arrays shall be permitted to use the metal frame of a building or structure if the requirements of 250.52(A)(2) are met.

 

[Gavin Stone]

It seems to read to me that a local grounding rod is within code. https://www.electricallicenserenewa...ation-Courses/NEC-Content.php?sectionID=384.0

From what I’ve read it’s “permitted” to have a local grounding electrode at the array. But code still requires a ground wire back to the main grounding rod.

 

[SeaGal]

The fellow in the video does a good job of walking through it all. His method of testing for electricity using his finger is not one I would recommend.

I agree... a tongue is a much more sensitive bodily part for detecting stray voltages

Seriously though, obviously need to adhere to local regulations and the earthing arrangement in different countries

We have TT earthing here and my ground mount panels are grounded right by the panels themselves. IMHO, if my panels are grounded right next to where I'm standing I'm not going to get zapped - we'll all be at the same voltage. If they are grounded 300ft / 100m away there is more scope for a voltage difference across me.

 

[Crowz]

Anyone watched this?

 

[Mattb4]

From what I’ve read it’s “permitted” to have a local grounding electrode at the array. But code still requires a ground wire back to the main grounding rod.

I guess I read it different. As I mentioned if you have to please a inspector you end up doing however he decides the code reads.

 

[Crowz]

Ohh I just figured something out

Ok 12 minutes into that video I posted is where I had that light bulb over my head moment.

He says don't ground the panels and references an "internet guy" sticking a meter to his panels which I'm sure is a reference to @Adam De Lay on his test. Remember Adam where your cheap meter wouldn't read but 25 volts or something ac but the "good" meters read 120 volts? But connecting the cheap meter to the house ac plug showed 120 volts. I think that's just how weak the amps involved in this is.

So for lower voltage like what Adam tested your going to get that sizzle sound as he touched it. But eventually stacking enough volts its going to become dangerous. This is the same secret to how were running all those amps thru tiny 10 gauge wire from our solar panels via upping the volts to get around having to many amps.

Since I will eventually have 400 volts running thru those wires I could see this ac issue on the panel frames getting a bit painful. I agree with not grounding them to keep from creating a lightning rod with a bunch of panels which I will have one day in the field at my house. But I don't want to be cleaning up dead birds and other animals or getting bit myself messing with them so ground seems good. Also is this only leakage from the inverter side thus the 400 volts has zero effects? Seems like the dc voltage wouldn't matter but I don't know how the panel frames are getting energized to start with since they are not supposed to be connected in the first place from what I understand.

So what do we do?

 

[Gavin Stone]

I guess I read it different. As I mentioned if you have to please a inspector you end up doing however he decides the code reads.

That’s very true. I just saw someone that passed inspection yesterday on another forum. And it was definitely not to code. ??‍

 

[Gavin Stone]

Ohh I just figured something out

Ok 12 minutes into that video I posted is where I had that light bulb over my head moment.

He says don't ground the panels and references an "internet guy" sticking a meter to his panels which I'm sure is a reference to @Adam De Lay on his test. Remember Adam where your cheap meter wouldn't read but 25 volts or something ac but the "good" meters read 120 volts? But connecting the cheap meter to the house ac plug showed 120 volts. I think that's just how weak the amps involved in this is.

So for lower voltage like what Adam tested your going to get that sizzle sound as he touched it. But eventually stacking enough volts its going to become dangerous. This is the same secret to how were running all those amps thru tiny 10 gauge wire from our solar panels via upping the volts to get around having to many amps.

Since I will eventually have 400 volts running thru those wires I could see this ac issue on the panel frames getting a bit painful. I agree with not grounding them to keep from creating a lightning rod with a bunch of panels which I will have one day in the field at my house. But I don't to be cleaning up dead birds and other animals or getting bit myself messing with them so ground seems good.

So what do we do?

I don’t agree with not grounding them. Unless people are going to put rubber boots on their metal ground mount arrays this makes no sense.