Hi folks, new here and I’ll get right to this one since I can’t seem to get a straight answer from anyone anywhere. I have on my boat 2 battery banks. One’s for the engine (AGM), one for house (LFP). These banks are completely separate, e.g. do not share a common negative. It was set up this way in the past (with all AGM) so I just inherited that setup. I have an isolated Orion-TR that handles the charging of the house bank from the engine bank when the engines are running.
I also have a Multiplus 12/1600/70 that I want to connect to the house bank; so far, so good. On my previous boats however the ground lug of the multiplus was always connected to the negative DC bus, but since strictly speaking I have no “bus” per se now, where does it go? Negative post of my LFP bank?
For AC wiring, I would like opinions on this; I take 220v off my shorepower plug, this goes through an RCD, then from that RCD to a 16a breaker, and then straight to the AC-in on the multiplus. From the multiplus’ AC-out I go to a 2nd RCD, and from there it distributes to the various AC breakers for my AC loads.
So. Comments? Suggestions? Yes I’ve read wiring unlimited front to back, still doesn’t answer the question very well 
Hoping someone here can shed light.