Hi Jeff, love the shows! I'm doing a total re-wiring job on my boat. The previous owner used extension cords, parallel 18 gauge as a single wire, and solid wire for the shore power. My boat is nothing but DC now. I've gone to an electric drive as well (48 VDC). I will have 2 DC systems, house and motor. Do I have to ground a DC system? How and where would I do that? The shaft is isolated from the motor. Do I ground to a thru hull? Thank you so much for your input. - Jeff
All of the DC systems 48 volt and 12 volt should have a common connection point, typically the best place to do this would be the engine chassis. Your through hulls and shaft should also be connected to this common grounding system.