I have 240 plug with a switch dedicated for Air compressor. I have compressor that supposedly can be wired for 240V

2 pictures show sticker and current wiring. How do I update wiring to make it 240V? Do I just replace hot/neutral with hot/hot?

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EDIT: To finish conversion I have 1 more question: This is compressor, so there is switch (see picture below) From what I understand I keep wiring at switch the same but white will be second hot instead of neutral?

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1 Answer 1


Do I just replace hot/neutral with hot/hot?

Absolutely not! You have a vital step to complete before you can do that.

Note that the bottom picture would have been a little better if you had pulled the cord up so we could see the numbers on the white plastic block.

In this motor, you are working with two sets of wires, the electrical cord and a pair of jumper wires that go to the motor windings. These are the white and brown wire that go from the spade terminals on the white block down inside the motor (designated by arrows below).

Referring to the label, for conversion to running on 220/240V power:

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  1. The brown motor winding wire needs to be disconnected altogether. It gets removed from spade terminal #2 and pushed into what they refer to as the #6 pocket.

  2. The white motor winding wire gets pulled off the spade connector on connection #4 and moved over to the spade terminal #2

  3. The 240V power then needs to have each hot connected to it's respective LINE terminal in the pressure switch. The factory wiring between the pressure switch MOTOR terminals and the white motor terminal block for terminals #1 and #4 should be left alone

Basically, you are taking a pair of windings that run in parallel for lower resistance at 120V and changing them to run in series so the coil winding has higher resistance for 240V.

Note: Amended point 3, power input connects to the pressure switch, not directly to the motor...

  • Can you help with another question or I open 2nd question? See edit.. Wiring on top goes to motor, so I will keep that wire, just change wiring at motor as you said. What about "LINE" wiring? Should I just bring hot/hot to terminals and call it done?
    – katit
    May 14, 2013 at 17:39
  • I forgot about the switch. It will be between your line input (power cord) and the motor. Where does the power cord attach? That would be where the line connection goes. May 14, 2013 at 18:10
  • It's on my picture (I edited main post) - black/white LINE is what going to outlet (110v) right now and black/white MOTOR is what going to motor (second picture)
    – katit
    May 14, 2013 at 18:12
  • Yes, the LINE side of the pressure switch is where the 220V hot/hot wires should be attached. Power from wall goes to pressure switch LINE terminals, switched output MOTOR terminals go to motor and the motor gets the jumpers swapped to change it to run on the higher voltage. May 14, 2013 at 18:21

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