Sizing circuit breaker and cables

Single-Phase. :-)

Cheers! Rich

A leg. The black leg or the red leg. Or, simply a "hot"; again, the red one and the black one.

Cheers! Rich

No, they are not. In fact they are the same signal, just from one end or the other. They are precisely "in phase", simply polarity inversions of each other.

And please learn to trim and bottom-post.

Thanks, Rich

It is really no different then a unipolar stepper motor with a

Well to be utterly pedantic about it, a polarity reversal is equivalent to a 180 degree phase shift for a sinusoidal signal...

There is none. It is a single phase supply with a center tap.

That seems to me to be a distinction with no difference. Is there something magical about mains that come into the house with two phases versus deriving two phases via a transformer? After all, the power company derives its phases using transformers, too.

With respect to the center tap the signals at the ends of the secondary are 180 degrees apart. The mains supply may be single phase, but the secondary circuit of the transformer has two phases available with respect to the center tap.

Instead of one end being grounded the center tap is. Otherwise no difference.