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George Grub asked

12V DC Off-Grid System - Grounding help PLEASE

Hi All,

I just built my first 12V DC off grid system (I'm not an expert by any means) and have some questions re: grounding / earthing.

Note: this system is standalone - it's not connect to the household AC in any way.

From what I've read, and research done, "the purpose of ground wire is to provide a path back to the source of the electrical current - the main electrical board - in the event of a fault" and "NOT to provide a path to the ground, or to some road buried in the ground".....See image below for where I sourced this information

As such, I intend to ground my system as outlined in my conceptual diagram below (see dotted green lines). That is, attach a 6 AWG wire from Inverter ground screw and Victron MPPT controller ground screw to the negative bus bar and then run 6 AWG from negative bus bar to the grounding point in the Solar junction box (apologies if that is not the right terminology). I believe the grounding point in the Junction box somehow connects the household AC ground wire (that's what the solar guy said).

My main question therefore is ------> does this ground wiring look right, is it correct / safe?

Kind Regards


PS, yes, I've read that technically you don't need to ground a 12V system, but I don't mind if I do, and I guess I just want to be super safe and also understand how to do it.

PPS, I've read that the grounding wire needs to be one step down from your maximum rated wire (in my case 2/0 AWG), but I've also read that you can get away with 6 AWG. However, if I was to go one-step down, then I very much doubt I could work with 1/0 AWG would be just too thick to work with (e.g. connecting to the Junction Box, connecting Inverter & MPPT to negative bus bar).

12V off-grid system - Conceptual Diagram


12V off-grid system - actual setup


What is the purpose of Ground Wire?



MPPT ControllersGroundingdc system
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