How to Connect a 120-Volt Appliance to a 240-Volt Circuit

It isn't a common procedure to plug a 120-volt appliance into a 240-volt circuit, but it is possible to do it safely. The plugs and receptacles for the two types of circuits don't fit together, so you must access the circuit wiring. While you can hardwire an appliance cord directly to the terminals of a 240-volt receptacle, a safer alternative is to cut the female end off of an old extension cord, connect it to the terminals and use it as a plug. That way, you can cover the terminals while you use the appliance.

Old extension cord
Utility knife
Screwdriver

Instructions

- 1
  Cut the female end off of an old three-pin extension cord with a utility knife. Cut the cord about 2 feet from the plug so you have a little extra cord with which to work.
- 2
  Strip about 8 inches of sheathing from the end of the cord with the knife and separate the wires. There should be one covered with black insulation, one covered with white insulation and a ground wire, which is either bare or covered with green insulation. Strip an inch of insulation from the end of each wire.
- 3
  Turn off the breakers controlling a 240-volt receptacle from which you can draw power. It may be a receptacle for your dryer, stove or another heavy-duty appliance. Typically, 240-volt circuits are controlled by a pair of coupled breakers. When you switch one of them off, the other will turn off automatically.
- 4
  Unscrew the cover from the receptacle with a screwdriver and unscrew the receptacle from the electrical box. Pull it out and examine the terminal screws on the back. You will see two brass ones. A red wire is connected to one and a black wire to the other.
- 5
  Loosen one of the brass screws. The wires connected to the screws are interchangeable, so you can choose either one. Wrap the black wire from the extension cord around the screw, then tighten it securely. Give the extension cord wire a little tug to make sure it is securely fastened.
- 6
  Connect the white wire from the extension cord to the silver terminal screw on the receptacle in the same way. There should be a white circuit wire already connected to it. Connect the ground wire from the extension cord to the green terminal screw on the receptacle.
- 7
  Screw the receptacle back to the electrical box. Make a notch in the drywall with the knife into which the extension cord will fit, then screw the cover plate back onto the receptacle with the extension cord extending out.
- 8
  Turn the breakers controlling the circuit back on. Plug the 120-volt appliance into the female end of the extension cord extending from the receptacle.

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