On Wed, 05 Jul 2006 01:24:28 +0100, Gibbo
wrote:

Pete C wrote:
On Tue, 04 Jul 2006 17:57:27 +0100, Gibbo
wrote:

I think the easiest way to make your mind up is this. Consider how
many possible places there are on an average steel hulled boat for live
to come into contact with the hull. Then consider that if this happens
it will almost certainly not trip the shorepower MCB and, particularly
in fresh water, is very also far from certain that it will trip an RCD.

I think it's pretty certain.

I don't. In fact I *know* it is *far* from certain. Especially in fresh
water.

Well without any data to back it up, both our opinions are pure
speculation.

I do know that a sniff of relativly pure rainwater is enough to trip
an RCD.

Deaths are on record (see below) in the USA where their RCDs
(they call them GFCIs) act at 5mA not the usual 30mA here.

That article makes no mention of GFCIs, nor are they required in the
US for shore side protection.

European RCDs
usually trip at 30mA. A swimmer will become paralysed at *far* less than
this.

Yes, but at that point the RCD will cut the supply and prevent
electrocution.

Not with a swimmer. 5mA will probably paralyse a swimmer. He then almost
certainly becomes a drowner as opposed to a swimmer. This is *way* below
the trip current of the RCD.

This assumes a live hull can leak less than the RCD trip current to
its surroundings.

Multiply these together and you get an infitesimally small
probablility.


Infitesimally small? Then how do you explain this?......

http://www.mikeholt.com/newsletters....&lett erID=36

The US already have a code that calls for earth bonding. But it *isn't
working*!!!

They need to have a rethink and investigate additional safety
measures, including shore side GFCI protection.

Also quite a number of the fatalities in the above report are due to
faulty shore side/line wiring, that proper grounding of the boat will
do nothing to prevent.

This helps to show that shore based GFCI protection could be extremely
worthwhile.


Have a look at this:

http://www.dbw.ca.gov/PDF/MarinaGuide/SectionE.pdf

"5.6 Ground fault circuit interrupters (GFCI) are not required by the
NEC on receptacles that supply shore power to boats located at marina
berths, wharfs, piers and other similar boating facilities.

E5.7 It is not recommended that GFCIs be provided on electrical
outlets for
individual boat berths. To do so may invite some or all of the
following problems:
nuisance tripping of the devices
emotional friction between marina staff and boat owners
false sense of security
unnecessary increases in operation and maintenance costs

E5.8
It is highly recommended that dedicated 120 volt 20 amp GFCI power
outlets be provided on marina docks for use by maintenance staff. Such
dedicated outlets should be provided at logical locations for this
purpose, and are required by the NEC to be equipped with GFCIs."

Shows that a higher priority is placed on 'emotional friction' than
safety!

Read the rest of it.

Or, in particular, this......

http://www.abycinc.org/lucas_ritz.pdf

It does call for proper grounding and GFCIs:

"The bottom line was that if the boat had been properly wired or a
GFCI placed ahead of the shore power cord, we would have our son
today. This started my asking questions as to why GFCI’s were not
required."

Anyone who says hull bonding is not required and that to fail to bond it
is not dangerous has *no* idea what they are talking about. No idea
whatsoever.

Read the above reports, it is required in the US, while the
requirement is perfectly sound, in practice it doesn't always work.

People have died as a result of retards not bonding shorepower earth to
the hull. All because some idiots say it isn't necesary.

Furthermore, earth faults happen for a variety of reasons, not just
wilful negligence.

It *is* necessary. That is why the ABYC want it, that is why the RCD
demands it, that is why there is now such a large market for galvanic
isolators and isolation transformers. Because all sensible people bond
earth to the hull.

You're on your own here. One of the relics who think isolated systems
are safe and not a danger to other people.

I've never said I thought that.

I agree it's necessary in the current circumstances, but that it's not
a great solution so other safety measures should be investigated.

I think the reasons that shoreside RCDs are not legally required in
the UK is for historical reasons, not that is has been properly looked
into.

If the BSS investigated it in a proper way and concluded it wasn't
worthwhile, I'd be perfectly happy.

To the best of my knowledge, it hasn't been, and becaused it's not
part of a boat, it's unlikely to be.

Now, I'm sure the BSS people can read this and correct me if I'm
wrong...

cheers,
Pete.
(x posted to rec.boats.electronics for comment)

Pete C wrote in
:

emotional friction between marina staff and boat owners
false sense of security
unnecessary increases in operation and maintenance costs

E5.8
It is highly recommended that dedicated 120 volt 20 amp GFCI power
outlets be provided on marina docks for use by maintenance staff. Such
dedicated outlets should be provided at logical locations for this
purpose, and are required by the NEC to be equipped with GFCIs."


They care about the maintenance staff, whos family would probably sue their
asses over the death of their husbands/fathers, but don't give a **** if
some boater gets zapped from a faulty appliance inside his boat he can't
sue them about.

How nice, eh?