Proper place to ground AC system/shorepower

[Maestro]

Wondering where the proper place is to ground the AC system. Right now my AC system is very simple. Shore power comes into two breakers which then have wires going to a few wall outlets in the cabin. That's it...but I can't tell where it's grounded to.

I have acquired a nice 3-stage marine battery charger and would like to install. Want to make sure it is done properly. Thanks...

[barkleydave]

You are entering on thin ice. I noticed the first concern.

ABYC/USCG requires you have a Double Pole main breaker (on the boat) A double pole breaker breaks both the Hot and the Neutral.
Your internal AC on board is a Floating neutral which means it is NOT tied to the Safety Ground. When you are on shore power you MUST have a complete safety ground( from the pedestal) to you boat inlet. You also should have a Galvanic Isolator or transformer. This is tied to the Green safety ground and prevents stray DC current from running through your hull. (DC is the bad one for corrosion/AC is the KILLER) When you are connected to shore power the Green Safety ground goes directly back to the shore power pedestal and to an earth ground.

I am NOT MAKING ANY RECOMMENDATIONS FOR WIREING. I STRONGLY RECOMEND THAT YOU HAVE A CERIFIED MARINE ELECTRICIAN DO THE WORK OR AT LEAST GUIDE YOU AND INSPECT YOUR INSTALLATION.

You mention that you acauired a marine battery charger. If it is placed in a bilge space should be hard wired to a breaker. (not plugged into an outlet if it is in an unprotected engine/fuel space.

Here is a link to help you get started.

http://www.westmarine.com/WestAdvisor/DIY-Shore-Power

safe boating,
dave

[Maestro]

Dave, your wisdom is always appreciated...thank you.

So far everything I am finding indicates that the AC ground (with Galvanic Isolator properly installed) should connect to the engine negative terminal.

Is this proper on our boats?

[barkleydave]

Correct
Floating neutral when on ge fault will trip breaker
Also you want all outlets protected wit GFIC

[railrunner04]

Hopefully its not the same as we found when tearing out the electrical two bridged 15 amp breakers absolutely no ground to the hull anywhere copper wires running over hard edges it was a horror show we're lucky no one got electrocuted.
Being that you have a 1970 and the setup sounds errily familiar it makes my hair stand on end!

P.S. it can be redone diy but like dave says best left to professionals if your not comfortable wrangling the electrical pixies in a marine environment