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From: Peter Bennett (no email)
Date: Thu Jan 01 2004 - 20:50:49 EST
Thursday, January 1, 2004, 2:45:26 PM, Bob wrote:
> A related question re twin 30-amp cords and outlets vs. one 50-amp circuit.
> A boat I looked at the other day had two 30-amp power cords, two 30-amp
> connectors and two "shore power" selections on the master AC panel. I'm
> familiar with the practice of paralleling two 30-amp circuits to provide
> more amperage to the boat, but why then have two independent switch settings
> on the master AC panel, one for "Shore Power 1" and the other for "Shore
> Power 2"? The AC panel has a large input selector that can choose
> "Inverter", "Generator", "Shore Power 1", or "Shore Power 2". The point I'm
> missing is why have separate selector settings for SP1 and SP2? I can see
> paralleling the two shore power circuits together, either internally or via
> an adapter, but why if two 30-amp outlets are available on the dock, would
> the builder have provided a means by which to select one or the other 110
> VAC cord, but not both?
> Any ideas?
> Thanks, Bob Peterson
Were the shore power inlets on opposite sides of the boat? I think
the switch setup you describe would make sense in that case - you
connect the shore power cord to whichever inlet is easier or will
allow it to reach a dock outlet.
It the boat is to be set up to use one or both inlets, then
somewhat fancy switching will be required, as the electrical code
and ABYC require that both the hot and neutral conductors from each
inlet must be isolated from the corresponding conductors of the other
inlet. The AC distribution panel would have to be broken into two
sections. If you are using a single inlet, both sections (hot and
neutral) are fed from that inlet, but if you use two inlets, the hot
and neutral of the second section must be disconnected from the first
inlet, and connected to the second.
On further consideration, a four pole four position switch could
handle this, and the "Shore Power 2" label may just be a little
misleading. The AC panel would still be split, but the "Inverter",
"Generator", and "Shore Power 1" positions would feed both sections
from the selected source. The "Shore Power 2" position could feed the
two sections of the AC panel from the two inlets. I suppose that you
could arrange the "Inverter" position to only feed the inverter to one
section of the AC panel - so you can't have the inverter run the water
heater or air conditioner.
-- Peter Bennett, VE7CEI Vancouver, B.C., Canada GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver-webpages.com/van-ps _______________________________________________ http://lists.samurai.com/mailman/listinfo/trawler-world-list To Unsubscribe send email to Include the word "Unsubscribe" (and nothing else) in the subject or body of the message.
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