Dealing with a boat fire, checking for a common cause
 

"Gould 0738" 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.

Exactly the sort of wondering from which
(a few, and very small) fortunes have been made! :-)

GFI says you do not have as much current coming out on the Neutral lead as
going in on the hot lead. In otherwards another path (ground / you) for
current. The bad connections do not leak to the other posts, they just
created heat because of the resistance of the connection. Sort of like a
heater plugged in to the power. So the fires starts and the GFI is happy
until something shorts. The GFI shoud be required for safety, just like on
a swimming pool, but will not stop the fire from bad connections. You can
make a 2 wire circuit safe by having a GFI breaker in the circuit. Helps in
old houses when you want to run 3 prong plugs. And I think it is code most
places.
Bill

Dealing with a boat fire, checking for a common cause
 

Probably because a 30 or 50 amp GFCI breaker somehow encapsulated as
part of a shorepower cord would add about $300 to the cost and darn few
boaters would buy one and what would it do to prevent the scenario
described?

There is already a breaker on the dock, right? All an additional GFCI
breaker would do is open when the slightest leak occurred to ground. Any
short drawing less than the rated current (more than enough to start a
fire) would be ignored unless the ground conductor was involved. Plug a
hair dryer into the bathroom GFCI outlet, and you will see lots of
glowing wires available there. There is nothing in a GFCI to prevent the
same glowing wires in your shorepower socket.

Rick


You're right, in his situation a GFCI probably wouldn't have tripped, but a
AFCI (Arc Fault Circuit Interrupter) would have.
I've seen 50amp GFCI's for around $150, but I have no idea how much a AFCI
would cost (if even available at that amperage).

Dealing with a boat fire, checking for a common cause
 

Joe wrote:

You're right, in his situation a GFCI probably wouldn't have tripped, but a
AFCI (Arc Fault Circuit Interrupter) would have.
I've seen 50amp GFCI's for around $150, but I have no idea how much a AFCI
would cost (if even available at that amperage).

I don't know either if AFCI's are available over 20 amps, that is as
high as I have seen them. Can't imagine why the technology couldn't be
applied to any breaker size though. Maybe there isn't a market for them
above those required by the codes.

If they are available, don't cost too much, and would work upstream of
multiple branch circuits I would seriously consider building one into my
switchboard. My shorepower cord is hardwired to the switchboard and
would not benefit from an AFCI.


Rick

Dealing with a boat fire, checking for a common cause
 

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.

Dealing with a boat fire, checking for a common cause
 

Because on 95% of boats, they would trip all the time due to current leaks.
Also would cost more for the marina.

"Jim Irvine" 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.