[ianburrell]

US three-phase power is mostly 208V, 240V, and 480V. The 208V is what normal residential 120/240V split-phase was made from. 240V is high-leg delta three phase and I think was old alternative to split-phase. 480V is used for light industrial that needs more power.

There is nothing in US power system that is 220V.

[IWeldMelons]

Ackshually, you need to tell that the GP of the thread, they began using "220v".