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I see that I need to have a chassis ground for when I install my Victron multiplus 12-2000watt inv/charger in my travel trailer. The Victron manual doesn’t say anything about size or type of cable to use for this. I have seen some posts that seem to say I don’t need it at all and others that say it should be the same or one size smaller than battery wiring (which is 2/0). Any advice on this and is it okay if I connect it to existing chassis ground (where other bare copper wires attach)?
Thanks
earthing questions is one for your electrical contractor to answer.
That being said, I understand that an ABYC standard (US boating standard) requires safety ground to be sized for DC return. The backstory I saw somewhere was that inverter failure could force DC return onto the safety ground (which if not adequately sized becomes a fire hazard).
So it looks like I should be running a 2/0 cable from inverter case to the chassis of the trailer. Is it okay to take this cable to the existing chassis ground bolt where the ground (8 gauge bare copper) from the AC circuits attaches to chassis? Or should they be separate chassis grounds?
Your inverter case earth ground cable (terminal labeled PE for "protective earth" on Victron inverters) needs to be no smaller than 1 size less than the DC negative cable. So if you have 2/0 for the DC cabling you need at least 1/0 for the case ground. It needs to be separate cables to the DC neg bus(do NOT connect the DC neg input terminal directly to the PE terminal). For safety, there needs to be a separate path to ground in case you get a short to the inverter case, and it needs to be large enough to carry the full current until it blows your fuse or trips the breaker.
I always use the same size cable for the PE as I do for the DC input. Saves from having to buy 2 different cable/terminal sizes, and is 100% certain to be able to handle any fault current.
