Hello,

I am redoing my 1967 sailboat wiring as minimally as possible.

Here’s the situation:

• There is no inboard and my outboard has it’s own dedicated lead acid starter battery.
• I do not want to mix the outboard starter battery system and the house batteries.
• I do not want to ground the house batteries on the outboard.
• The two 12 volt gel house batteries worked great until I hauled out and removed the prop and shaft from my former inboard engine. After that I had no more ground and subsequently no more battery power.

Here are my questions

• Where is a good place to ground on the boat if I have no metal through the hull (I believe the cap on the sink drain is brass and the fish finder radar is sticking in the water, otherwise all plastic)?  Options include a “floating” bus bar, a bolt going through a chain plate open to the cabin, any old random bolt in the hull or???
• I am using one of the Ancor double pole breakers as a main shut off for the shore power. I wish to split off of the main breaker to two separate breakers controlling Port and Stbd side outlets (so I can turn lights on as I enter the dark cabin). I bought the Ancor 30 amp breaker that is made up of two connected breakers each labeled 15 amps. How do I correctly wire the hot and neutral shore power wires to the four possible screws on the double breaker so that it controls the full possible 30 amps coming from shore?

Thank you.

Hi,

If your boat wiring only had DC systems on board, I wouldn’t worry too much about your DC ground connected to a through hull fitting.

Adding shore power changes things.

In my opinion, to keep the system safe, you need to have a common DC ground. All DC negatives need to be connected together (including the ground from your outboard motor). The AC ground (green) needs to be connected to the DC ground.

This document, ABYC E-11, beginning on page 32 will help you with designing your AC system.

Hope this helps,

Kevin