Larry, it is quite difficult to prevent your "independent" DC system
from being connected to the AC ground bus. Like it or not, it is
probably connected through the water, providing an opportunity for a
potential difference between your DC ground system and the grounded case
of an AC appliance. An improperly wired boat in the next slip can cause
real safety problems aboard you vessel.

You can safely isolate your system from the galvanic couples you fear
with an isolation transformer or a galvanic isolator. I know you are
well aware of both. You can also isolate your underwater metal (prop,
shaft, etc.) from both the AC and DC ground systems, which may be what
you meant to suggest.

Chuck


Larry wrote:
Marc wrote in news:ufm1p1h2l7qr8s8vs3vbso6j1so1l3apgr@
4ax.com:


Having disconnected and labeled all the 12 V wiring, the 110 AC is
now visable. It appears that all the AC ground wires (green) are run
to a common buss. But , then, the AC Ground buss is connected with
a 6 ga. wire to the DC negative buss. This doesn't seem right to me.
Is it?


They do this to insure your engine, underwater propulsion gear and
everything hooked to the DC ground system is connected to every other
stupid boat and the marina's big earth ground system, making one HUGE
battery out of those zincs you can't figure out why they disappear so
fast.

There's absolutely NO reason why the independent DC system should be
connected to the AC ground bus I know of. Ours isn't. I'll be damned if
I'd pay with MY zincs to protect your prop because my zincs are hooked
through the AC wiring ground to your zincs.....

Oh, hooked up like that, too, your zincs are protecting the whole
electrical system of HIS marina any place it touches the water or makes
contact with the earth.

Aren't you being, inadvertently, nice....(c;