At 15:33 -0700 24/7/09, [email protected] wrote:
Hmmm, I wonder how the birds can sit on those same HV wires and do
just fine? If a wire is not referenced to the ground you are
standing on, touching it would not give you a shock unless you were
also in contact with the other conductor it is referenced to.
It's a safety issue only when there is a fault. In the event of a
fault that connects a hot wire to the battery system then the battery
system will become hot. Making sure that neither pole of the battery
is grounded will not prevent this in fact it will make it possible.
If the HV system has a grounded conductor then the other one will be
hot and any associated wiring systems need to be grounded for safety
in case of contact.
At 15:48 -0700 24/7/09, [email protected] wrote:
A single pole switch will stop the current regardless of whether
one of the conductors is referenced to ground or not.
If one pole is neutral and the other is switched off then the circuit
is safe. But if the system is 'floating' and you only turn off one
pole then the circuit is still live. You have stopped the current
but you have not necessarily made it safe to work on. If neither
pole is grounded then both must be treated as potentially hot.
That's why it's actually more expensive to have 'ungrounded' systems.
You will still need to have grounding conductors for safety and you
will need to double the number of fuses, breakers and switch contacts.
--
Hugh Piggott
Scoraig Wind Electric
Scotland
http://www.scoraigwind.co.uk
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