Many foreign countries require a GFCI (or RCBO, same thing in the UK) in the
shorepower. USA boaters count your blessings, as this is one place where
our regulations make sense. GFCI devices in the main shorepower connection
are subject to nuisance tripping as salt air is wonderful for producing
small current leakages.

You would have the same problem on seaside houses if GFCIs were required in
the main breakers. A GFCI must not trip for small leakages (microamps) that
are caused by moisture and must trip with currents in the 30ma range which
might be killing someone. On a branch circuit, this is possible. On a
main, with tens or hundreds of devices downstream that might be leaking 50
microamps each, it's impossible.

Nuisance trips are very frustrating, as all you can do is clean all the
connections carefully with distilled water and pray. On a boat without
isolation transformers, you might have to clean all the AC devices in the
boat, although finding the problem is easier if every circuit at the panel
has a switch in both hot and neutral leads (this is legal but not the usual
practice in USA wiring, but a ground fault on the neutral side is almost
untraceable if all the neutrals are common.)

On larger craft subject to class surveys, it is fairly typical to high-pot
(test the insulation of) all the wiring, every five years. This will turn
up problems that would pop a GFCI, but who has ever seen a high-pot on a
smaller boat? This is partly, I'm sure. because the testers cost over
US$1,000.

As noted in another place in this thread, a GFCI won't deal with arcing. I
suspect that arc fault detectors would suffer from the same sort of
problem -- nuisance tripping -- if you tried to cover a whole house or boat
with one.

--
Jim Woodward
www.mvFintry.com



"Joe" wrote in message
...
I wonder why these power cords do not have a simple GFCI in-line
breaker
that would trip and warn the user when any of the connections are
starting
to go.

That would be nice. Probably only cost an extra $25 or so.

DSK


What's strange is that the 2002 NEC requires that GFCI outlets be
installed:
"outdoors, in boathouses, in buildings used for storage, maintenance,
repair, where hand tools, diagnostic equipment, or portable lighting is
used", but has no GFCI requirement for shore power.

Even specifically states that these requirements are for "Other than shore
power"

Makes no sense to me.