Re: disinformation
120 V single-phase in North America and Japan, 220-240 V two-phase in most of the rest of the world
IIRC the US and UK are both 3 phase systems. Most power goes into 3 phase motors in industry. Dwellings get one phase at the familiar domestic voltages. As frank ly points out, houses in a street get alternate phases for balance, and you can sometimes see it where the wires are overhead - a "drop cable" to each house from one of the 3 main street conductors (each on a different phase).
I guess the US spins it generators at 3600 rpm, giving the 60hz. We are more relaxed in the UK, with 3000/50Hz.
Biting the hand that feeds IT
