Grounding of PV panels

NBDrancher

I am installing a 2nd array of 3 x 285 watt panels on a pole mount with a Midnite Solar combiner box/lightning arrestor. I mounted the box to the pole of my first array ( 4 x 175 watt panels). The installer did not ground them when he did the job and I want to ground it all but am not sure if I should drive a ground rod right near the pole or run a separate wire to the ground rod at the small building that houses the Outback inverter, charge controller, batteries and disconnects. Any help would be appreciated.

mike95490

How deep is the pole in the ground ?  packed dirt or concrete ?   A 10' iron or steel pole in concrete is a really darn good ground.

NBDrancher

12’ pole, 4 feet in concrete. The other is a 10’ pole, 42” in concrete. I guess you answered my question Mike. 

mike95490

Maybe,   You need 10' of pole down into the concrete.  The metal & concrete create a very efficient ground.   The big lump of concrete is much better than 42" of concrete

NBDrancher

I will be installing a 8' copper-clad ground rod beside my first array.  Digging a 10' hole in the caliche here at the ranch would be tough. 
 

andtime

Wow, great info! On a similar track, I have my four 100w panels on a small wood frame rack sitting in concrete deck blocks. I am not using metal rails--just wood--so panels are not joined together at all. Soil is very rocky, not sure I can drive a rod very far. Any ideas for how I can ground? some kind of jumper between the panels' frames, and then a rod driven only a foot or so into the ground--would that be better than nothing?

BB.

Do you have a chance of lightning in your area (one good reason for ground solar panel frames)?

If you want to ground (with 6 AWG bare wire from panel to panel to ground rod/plate):

https://www.solar-electric.com/gbdbtsopagrl.html

The idea is that you do not cut the 6 AWG--You just drop it into the "slot" and tighten the binding screw.

For grounding, some folks have rented a hammer drill and driven a ground rod into the earth:

You can find ground rod driving adapters (and some folks have driven by placing the hammer drill over the rod):

https://www.amazon.com/Bosch-HS1924-Ground-Rod-Adapter/dp/B0009H5POU

And if not possible to drive an 8 foot rod--Burying a 12 inch square plate 30" deep can work too (or whatever your code requires for ground plate/ground rod options):

https://www.harger.com/product/ground-plate-assemblies
https://www.hunker.com/12445983/how-to-install-an-electric-ground-plate

-Bill

andtime

BB. said:

Do you have a chance of lightning in your area (one good reason for ground solar panel frames)?

If you want to ground (with 6 AWG bare wire from panel to panel to ground rod/plate):

https://www.solar-electric.com/gbdbtsopagrl.html

The idea is that you do not cut the 6 AWG--You just drop it into the "slot" and tighten the binding screw.

For grounding, some folks have rented a hammer drill and driven a ground rod into the earth:

You can find ground rod driving adapters (and some folks have driven by placing the hammer drill over the rod):

https://www.amazon.com/Bosch-HS1924-Ground-Rod-Adapter/dp/B0009H5POU

And if not possible to drive an 8 foot rod--Burying a 12 inch square plate 30" deep can work too (or whatever your code requires for ground plate/ground rod options):

https://www.harger.com/product/ground-plate-assemblies
https://www.hunker.com/12445983/how-to-install-an-electric-ground-plate

-Bill

Thanks, Bill! No more lightning activity than normal, I guess--Northern MN. Thanks for the adapter pic, I can handle that. Hadn't heard of the square plate, I will definitely look into that. Soil is more rock than anything, hence, I'm worried about driving anything very deep without hitting ledge rock. 

SO appreciate the links---thank you!