I am aware that in the US normal low voltage power distribution is one of the following: - 120V/240V two phase split voltage - 120V/208V three phase - 277V/480V three phase - 120V/208V/240V high ...

Panelboards — Since 1975, panelboards supplied by a 4-wire, delta-connected, 3-phase system must have the high-leg conductor terminate to the “B” phase of a panelboard [408.3(E)]. Section 408.3(F)(1) ...