Boat ground question

[Glenn Ashmore]

I am finishing up my bonding and suddenly have a brain freeze. I have #6
green wire tied to all the exterior metal, the fuel tanks, the chain plates,
keel etc. They all come back to a central post mounted on the engine
stringer and tied to the block from there. AC neutral and ground are
separate back to the shore power receptacle but the Prosine inverter has a
boat ground that automatically disconnects when on shore power. .

Now the question. The stock alternator (used for the starter bank only) is
grounded through the block so the negative side of the starting battery is
connected to boat ground but the big house alternator and all the house DC
circuits are currently isolated. Should I tie the negative side of that to
boat ground too?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

 

[Steve Lusardi]

Glenn,
Yes, all earth references must be connected to a common point. You should
keep in mind earth cable resonance where applicable and use braided cable in
those applications, especially your SSB.

I know this is a bit controversial, but I would not connect the shore safety
earth. Instead, you should substitute safety earth with your own. In doing
so, you would isolate other substation power users ground leaks from your
hull, as your boat earth will be superior to the earth at the distribution
transformer. I am really paranoid about this and use an isolation
transformer myself.
Steve