How to Wire a 220-Volt Outlet With Romex Wire


A 220-volt outlet for an appliance or shop tool looks different than a standard 120-volt outlet. The two slots for the plugs are orientated differently. You can purchase 220-volt outlets to carry 15, 20, 30 or 50 amperes depending on the device you will be connecting to it. The slots will be in a different orientation for each one. All new outlets require installation of a ground wire which is included inside the sheathed cable or "ROMEX®" cable.

Things You'll Need

  • No-contact voltage tester
  • Cable stripper
  • Black permanent marker
  • Long-nose pliers
  • Screwdrivers
  • Multimeter
  • Turn off the electricity for the circuit you will work on. Test the wires in the wiring box with the no-contact voltage tester to ensure that the current is turned off. Turn on the tester and move the probe close to each wire without touching it. The light or buzzer will remain off if the current is off.

  • Strip 8 inches of sheathing from the ROMEX® cable with the cable stripper to expose the two insulated wires and the bare ground wire. One insulated wire is black and the other is white. Strip 3/4 inches of insulation from each insulated wire.

  • Grasp a wire with the long-nose pliers at the stripped end and wrap the wire half-way around the pliers, turning the end into a U-shape. Repeat this for all three wires.

  • Color the insulation on the white wire black with the permanent marker near the bare end for about 2 inches. This allows electricians to recognize that the wire is a current-carrying wire and not a neutral wire.

  • Loosen the three terminals on the outlet with the screwdriver. Place the bare ground wire on the green terminal screw with the wire going around the screw clockwise. Tighten the terminal screw firmly.

  • Connect the two current-carrying wires to the remaining terminal screws so the wires go around the screws clockwise. It does not matter which wire connects to which terminal. Tighten the terminals firmly.

  • Push the wires into the wiring box behind the outlet. Attach the outlet to the wiring box with the two supplied screws. Install the cover with the screws supplied with it.

  • Turn on the circuit breaker. Set the multimeter test range one level above 250 volts AC. For many meters this will be 500 volts. Insert the two multimeter leads into the outlet power slots. The voltage should read 220 to 250 volts. Test between either power slot and the ground slot and the voltage should read 110 to 125 volts.

Tips & Warnings

  • If the device uses 120 volts and 220 volts, such as dryers or ranges, it will need a neutral wire. In this case the ROMEX® must have two colored wires, a white wire and a bare ground wire. Connect the ground wire to the green screw, the white wire to the screw labeled "W" and the two "hot" wires to the remaining screws.
  • Never work on a hot circuit. Always turn the power off and test to make sure it is off.

Related Searches


  • "Wiring Simplified, 40th Edition"; Herbert P. Richter, et al.; 2002
  • "Code Check Electrical"; Redwood Kardon, Et al.; 2002
  • Photo Credit Jupiterimages/Comstock/Getty Images
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