The phase/s associated with this outlet. For single phase devices, this object will always return phase1(1). For 3-phase devices, this object will return phase1 (1), phase2 (2), or phase3 (3) for outlets tied to a single phase. For outlets tied to two phases, this object will return phase1-2 (4) for phases 1 and 2, phase2-3 (5) for phases 2 and 3, and phase3-1 (6) for phases 3 and 1.