I would offer a few points of clarification about all this:
1) People often refer to PP "manufactured leg", but being manufactured isn't the important point.? The PP produces Delta 3 Phase, which by definition has one leg at 208v to ground, and two legs at 120v to ground.? The 208v leg is called the "high leg."??
2) The high leg conductor is to be red or orange.? ?In fact, some people call it the "red leg" because of this.
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3) NEC says the high leg must be the B phase on panels:
408.3(E) Phase Arrangement. The phase arrangement on 3-phase buses shall be A, B, C from front to back, top to bottom, or left to right, as viewed from the front of the switchboard or panelboard.?The B phase shall be that phase having the higher voltage to ground on 3-phase, 4-wire, delta-connected systems.??
4) NEMA receptacle lugs are labeled X, Y, Z.? ?There is no code spec for mapping phases A, B and C to NEMA lugs X, Y, and Z.? But common sense is that the "middle" phase be consistent.? ?So the Y lug should be the high leg.
5) For motors, it makes absolutely no difference whatsoever which phase is connected to what, because motors do not use the leg-to-ground current and so they never see the 208v.
6) If you have an electrical component that requires 120v supply-to-ground and you connect it a 208v source (such as a Delta high leg), it's a problem.? ?This problem is not because the supply is "manufactured" nor because it's not "stable".? The problem is that it's the wrong voltage.?
