AC electrical refit

[Han]

Hi Everyone,

I'm in the process of planning an electrical upgrade for our boat. We live aboard full time and are always plugged in when at the dock, so I'd like to start with the AC system (currently 30 year old 14/2 household wire to the outlets, so definitely time for an upgrade). Our electrical system is pretty simple, we have 6 outlets and one battery charger (no inverter) that run on the AC. Currently power comes from the shore power outlet to the AC panel and then out on 2 separate circuits, one for the port outlets and one for the starboard outlets. The battery charger is plugged into an outlet in the engine compartment. I've purchased a new panel from Blue Sea and I'm planning on ordering new wire and some GFCI outlets, but I have a few questions first.

1. Currently the AC system is not connected to the DC ground, I've been reading Calder's book, and he recommends this to give the AC a path back to the shore power ground if there is a leak into the DC system. For us the only connection between AC and DC is the battery charger, so I'm not sure how much of a concern this is. Also we have no galvanic isolator. If I connect the AC system to the DC ground I would be worried about corrosion of our shaft and propeller. I guess my question is how much risk is there with our current setup? Is it likely that the AC can short into the DC system via the battery charger? also is galvanic corrosion possible with our current setup since the battery charger is grounded in the DC system? I'm considering rewiring things as they are (ie not adding a galvanic isolator and not connecting the AC to the DC ground), but I'd like to know if I'm being a total idiot. If the AC and DC were completely separate I wouldn't see a problem, but the charger being in there makes me worry.

2. What gauge of wire would be best to use? I'd like to go up to at least 12 gauge for the outlets, especially since we often have an electric space heater plugged in, but I'm wondering if I should bite the bullet (economically speaking) and use 10 gauge wire.


I hope that's all clear.

Thanks!