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From: (no name) (no email)
Date: Sun Sep 30 2001 - 13:38:23 EDT
In a message dated 09/30/2001 10:08:02 AM Atlantic Daylight Time,
writes:
> Neutral must be grounded to
> the ground and the water too, and there must be no electrical difference
> between neutral and ground. This is current code. Any electrical device
that
> has a two prong connector where one of the prongs is larger than the other
> is
> using neutral for ground. Having a floating neutral is dangerous,
> particularly
> in an environment in which one might inadvertently be touching water that
is
> grounded.
I don't believe the NEC applies to vessels.
I know for a fact that ships have a completely floating ac electrical system,
including the neutral in the 120/240 volt circuits. They also have ground
fault indicators and an engineer or electrician who chases down electrical
leakage. A floating neutral has the great advantage of being safe if there
is no leakage. One can touch a neutral or a hot while standing in the
bilgewater without danger.
Europe is wired this way, and they use 220, a much more potentially dangerous
voltage.
I have a floating neutral on my boat. There is a small 120v light bulb
connected where the jumper between the neutral to the grounding terminal
strips would be in a house. I also can switch out this bulb and simply
measure between the grounding system and the neutral system to check for
smaller leakage. Over the years I have had leakages and fixed them, one was
a box fan and one was a miswire.
I have never had any discernible problems with electrolysis in the twenty
years my boat has been in the water.
I have an isolation transformer for the 120 volt loads (240 split phase in,
120 vac out) which is primarily for presenting a balanced load to my genset.
I do not use a grounding line to the dock when I plug in to a dock (something
I have not done in years).
A GFI is unlikely to work in a marina. The evironment is just too moist.
There is leakage everywhere. I tried a GFI circuit breaker on my engine room
ac line but it only worked for a few weeks. The atmosphere was just too
moist.
Norm
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