Dr. Dickie
Member
- Joined
- Sep 23, 2020
- Messages
- 363
I am in the process of bonding and grounding the panels (I have some more of the clips coming later today). Are far as corrosion, that is why NEC requires stainless steel clips to do the bond between aluminum panels and the 6 AWG copper conductor. Copper to aluminum will corrode, stainless to either aluminum or copper will not--at least not as easily or quickly.I've read that when you do separate earth grounds at an array - it can setup a potential between other grounding points and actually be counter-productive. I presume this is why the electrician that did the roof portion of my system tied it into the house ground - e.g. probably rebar thru concrete foundation? - instead of doing an separate earth ground.
I have no idea on this - the more I researched grounding in terms of multiple ground points it seemed to be a mystic art with many opinions!
When I did my roof mount, I used the IronRidge system that bonds panel frames to the rails and the rails and the electrician grounded all this into the house ground. There are lightning arrestors in place outside at the combiner - so the ground wire is just 8 AWG.
When I did my DIY ground mount of galvanized pipe + universal strut + universal strut bolt accessories (to hold panels in place).....
View attachment 26559
the universal strut is all bonded to the galvanized pipe via metal tapping screws like this:
View attachment 26561
The vertical/horizontal galvanized pipe is bonded like this:
View attachment 26562
And the panels are threaded with grounding wire like this.... (FYI - the panels came with holes for this.)
View attachment 26563
And it's all grounded to the house ground (with lightning arrestors out at the array/combiner box) with 6 AWG twisted copper in the pic above.
I believe this is how it should be... but who knows! An electrical engineer friend (or maybe @Korishan ) - someone told me these bonds will likely corrode over time (like 10yrs) and not be very effective.
However, I did discover that one can actually do some tests using an Ohm meter with really long leads to verify that bonding is good / within accepted specs - but I don't remember the details.
Please tell me that code does no require that galvanized pipes that screwed together do not need grounding straps between them. And that the struts bolted together do not need individual grounding straps to each ONE!!
Good gosh, I will be here for weeks trying to do that! They are bolted together, I checked, no resistance between them.
Of to try to understand more of the NEC!
Also, OffGrid, what lightening arrestors are you using? If you know, it you don't, don't go to any bother, I will figure it out--pretty sure Midnite solar has some.