T&T: Shore Power and Electricity Concepts (LONG POST - was "Power Cords")

[Peter Bennett]

Tuesday, July 29, 2008, 4:14:46 PM, Gil wrote:

GJ> Jim's post was right on and well written.  I would like to add that although
GJ> residential 110/220V power is single phase, many will intuitively say it's two
GJ> phase power.  The rationale for this error is quite sound in that a center
GJ> tapped transformer will supply two outputs of equal, but out of phase power.
GJ> I'd also add that two 110VAC circuit breakers should not simply be ganged
GJ> together with an interconnecting pin as an equal to a 220V circuit breaker.
GJ> Some breakers, like Blue Seas, have overload sensing capability inside the
GJ> breakers that ensures both breakers trip when there is a fault on one leg.
GJ> Again, Jim's note was right on.
GJ> Gil

It is common practice (at least in shore-side wiring) to use two
single pole breakers with their handles tied together to protect a
120/240 volt circuit.  The breaker manufacturers make special
"gimmicks" to interconnect the handles for this purpose.  When one of
the breakers trips, the movement of its handle will turn off the
other.

It is also possible to get two breakers built together in one housing,
with a single handle for this purpose.


-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca