How to Run 220 Wire
Running 220 wire from a circuit panel to an outlet or directly to an appliance is sometimes necessary to power certain tools, appliances, and heating or air conditioning units. The 220v uses the same amount of current as 110v, but because the voltage is twice as high, the outlet is supplied with more power. Although 220 wire poses a greater risk of injury because of the higher voltage, it is ultimately a more efficient way of using power. Running the wire and installing it at the outlet is really no different than 110v wiring, although you may have to install a supplemental breaker at the panel.
Step 1 - Check the Circuit
If there is no 220v circuit connected to the circuit panel, you will have to install one. If one is already in place, shut the circuit down before you do anything else.
Step 2 - Install the Breaker
Absent a 220v circuit, install a 30-amp two-pole breaker. The 30 amps is the unit of current. It is two-pole, meaning each carries 110v and is doubled to 220v. Shut down the main power to the circuit panel before you install the breaker. Follow the directions that come with the new part. After you install the breaker, you can turn the main power back on, but keep the individual circuit shut down.
Step 3 - Run the Wire
Now take your 12/2 wire and extend a length of it to reach from the breaker to the location of the appliance or outlet you want to power. (The 12 refers to the gauge of the wire, while the 2 refers to 2 leads plus a bare copper ground.) Give it enough slack so the wire does not tighten up.
Step 4 - Cut Back the Wire
With the wire cutter or stripper, strip back 3 inches of the wire coating. You should see one bare copper ground and two colored wires, one red and one black. These three wires correspond with either the wires behind the junction box of the appliance or with the outlet. The red and black wires are both hot wires.
Step 5 - Connect to the Outlet or Appliance
On either the outlet or the appliance, connect the ground wire, followed by the black, then the red wire. Use wire nuts to properly secure them to the fixture. If you don’t have enough wire exposed, strip back a little more with the wire strippers.
Step 6 - Connect to the Breaker
At the 30-amp breaker, connect the ground wire, then the black and the red. Again, use wire nuts and check your connection.
Make sure all the wires are thoroughly attached to their respective ports. Turn the power back on for the new breaker and test the appliance or the outlet. If there is no power, you may have wired something wrong. In that case, turn the power back off and rewire. Running 220 wire is much like 110, only it comes with a greater risk of injury due to the higher voltage. If you have any doubts, contact a professional to help you with the job of running 220 wire.