chuck wrote in news:1vpRf.11533$S25.11273
@newsread1.news.atl.earthlink.net:

I agree: a plastic case on a double-insulated pot ought to be pretty
safe. What I really had in mind though was an appliance that had the
equipment grounding conductor connected to the case. Some electric
drills and other power tools possibly found on boats still use metal
cases and three-prong plugs. As for the mast, for many of us, the mast
is IN the galley, along with the engine, and most everything else. )



The drop-in-cord is still a 3-prong grounded AC feed. I don't understand
about connecting shore ground to the engine block and underwater metal
parts or the mast. The 3-prong grounded-through-the-drop-cord case of
the 120V fridge-from-Walmart is at ground potential. The only voltage
that's going to be on its case to the engine block in your boat is the
electrolysis DC potential between the metal conduit under the dock all
rusted out and leaking and your zincs, which will be fizzing away
protecting the rotting conduit if you connect their ground to your engine
block.

Is your mast grounded to the engine? Most are just floating to make sure
and lightning strike holes the hull to sink the whole thing so they can
sell you a new boat. Measure resistance between the mast and the
negative terminal on any 12V light near it. I bet it's an open circuit.
Grounding straps running through fiberglass boats costs them money to
install. You just know they're not going to do it, right?

I don't understand how grounding the AC line to the boat's DC circuit is
going to be "safer". If you get between AC "hot", the black wire, and
the boat's ground to the seawater, you get a shock limited by the
resistance of the connection to the seawater, which isn't much. If you
ground the AC line to all the boat's equipment, you get a shock with only
you as the resistance limiting the current that's going to kill you, just
like at home! How is that "safer"?? I'll be glad to come to your boat
and hold onto AC ground or neutral in one hand and the engine block in
the other, any time....grounded or not. I won't get shocked.

If we were interested in AC line safety, every marina would simply be
FORCED, the only way to make it happen, to comply with an NEC requirement
to install ground fault interrupters to all dock breaker panels out there
in the little post out front. Noone would ever get shocked, again,
unless they got right across the AC line to neutral. Of course, noone
would have any AC power in the boat, either, because the leakage of all
those old rusty fridges, water heaters and battery chargers would trip
the hell out of all the dock GFIs, plunging the boats in the dark,
too!...(c; Don't worry, noone at the marina or NEC cares.

Someone sent me a picture of total stupidity. This guy is standing in
his bare feet on a metal stepladder in the middle of a swimming pool in
his bathing suit. He's drilling a hole in the ceiling for something with
a metal-cased old electric drill. If you follow the cord back you see
it's plugged into a little brown 2-wire extension cord. You can see the
ground pin on the drill's electric cord sticking out in mid air. Totally
Stupid is right!...(c;