On Mon, 14 Nov 2005 10:14:18 -0500, Hoo
wrote:

My boat has two 120 volt circuits with a common neutral wire similar
to most homes. Normally they are supplied with 220 volts from either
a generator or shore power (120-0-120). There are no 220 volt
appliances or circuits out of the breaker panel.

I would like to be able to feed both 120 volt legs with a single 120
volt inverter through a rotary selector switch (both legs in phase,
instead of 180 degrees out of phase). There would be no possibility
of backfeed or cross connection with shore/generator power.

Does anyone know of any issues with doing that?

My only concern would be the size of the neutral wire.

When fed 120-0-120, the neutral current can never be more than the
current in either hot wire (it will actually be the difference between
the two hot wires), but if the two hot wires are in phase, the current
in the neutral will be the sum of the two hot currents.

If your inverter is 2000 watts or less, and the wiring is #12, you
will be OK, as the inverter will limit the total current to about 20
amps, and #12 wire is rated for that. If you have a larger inverter,
you may have to use larger wire.


--
Peter Bennett VE7CEI
email: peterbb4 (at) interchange.ubc.ca
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