120 VAC Outlet, single phase?

Discussion in 'General Electronics Chat' started by MichiganWolverine5974, Sep 12, 2016.

  1. MichiganWolverine5974

    Thread Starter Member

    May 13, 2015
    I bought a piece of equipment. The requirements are:
    115/230V 50/60 Hz (single-phase)

    I measured the voltages and this is what I measured:
    Line to neutral - about 120VAC
    Line to ground - about 120VAC
    Ground to neutral - less than 1VAC

    How do I know if this is single phase?
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    A standard 120V outlet is single phase. The ground pin is just a ground pin for emergency, chassis faults, not a current carrying by design.
    Therefore, a three-phase system would need four pins (hot, hot, hot and ground). You would have equal voltages across all three hot combinations. Those three equal voltages would most likely NOT be 120VAC in the US.
    MichiganWolverine5974 likes this.
  3. MaxHeadRoom


    Jul 18, 2013
    Just to add, two current carrying AC conductors are 1phase.
    Even when 2 phases of a 3 phase supply is used it is a single phase supply.
    MichiganWolverine5974 likes this.