On 11/23/13 4:37 PM, John G wrote:

You are of course correct but lots of people who know very little or
just enough to confuse themselves keep dragging PHASE into discussions
about houshold electrics.
The normal houshold supply in the USA is ONE phase with a centre tap
grounded to produce 120 volts above ground and 120 volts below ground or
240 volts between the ENDS :/



Well, what we think of as single phase isn't. It's actually two
phase. Trader 4 posted a link to an IEEE paper in another thread.
He http://tinyurl.com/lpwq82z
I work with irrigation which mostly relies on three phase power. We
sometimes tap power off grain bin sites which many times have "single"
phase 240. We'll use a transformer to produce 480 and add a phase
converter for the third phase. The converter adds one phase to the two
already there to run three phase motors.
It never occurred to me to think of "single" phase as actually two
phase until Trader posted the link. It has to be or phase converters
wouldn't make our irrigation systems run.
Granted, none of this probably matters to Joe Homeowner wiring a
garage light or a stove.