I had a licensed electrician install this circuit with NEMA 14-30 receptacle before I knew which specific appliance would be used on the circuit. I now have the appliance with a 14-30 plug, but it warns:

This is a single-phase device. Do not connect all three
phases of a 3-phase feed !!! You may use any two phases of a three- phase wye-transformer feed. The center-point of the three phases (usually used as Neutral) must be grounded somewhere in the system. A Neutral connection is not required by the LCS. Only Line 1, Line 2, and Ground are required.

Is this panel and receptacle properly wired for this single-phase appliance? PanelCircuit IdentifiedReceptacleReceptacleReceptacle

  • Are you sure that's a 240V appliance? Connecting across 2 phases of a 120V/phase 3-phase supply (as your instruction manual describes) gives you 208V, not 240V.
    – brhans
    Apr 12, 2016 at 19:17
  • According to the manual (here clippercreek.com/store/wp-content/uploads/2015/03/…) it will use a 208v L-L or a 240v L-L since it's probably an entirely switched-mode power converter.
    – Jeff Meden
    Apr 12, 2016 at 19:23

1 Answer 1


If you're not using the neutral, you should have a NEMA 6-30 receptacle instead of a NEMA 14-30.

Other than that, it looks like you're all set. The black wire is one line (L1), the red wire is another line (L2), and green is ground. You should have 240 volts between L1 and L2, since you have a 120/240V single split-phase system.

You don't have to worry about the three phase warnings, since you don't have a three phase system.

  • Would an L6-30 be acceptable? My plug choices are the 14-30 or L6-30. I already ordered the 14-30 since that was my receptacle, but I can still change it to L6-30 and rewire the receptacle.
    – Jesse
    Apr 12, 2016 at 19:06
  • 2
    Since there's not a neutral run to the receptacle, I wouldn't install a 14-30 receptacle. I'd either pull a neutral, or install a 6-30 receptacle. The L simply means "locking", so it shouldn't be a problem, as long as the device you're plugging in has a L6-30 plug on it.
    – Tester101
    Apr 12, 2016 at 19:12

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