How to: Dedicated 20 Amp Circuit 10-2 or 10-3

Turn off the main breaker. Remove the screws holding the panel cover while holding it in place with one hand. Remove the cover using both hands. Use the voltmeter to confirm that the power is off. Set the voltmeter to a minimum of 250 volts a/c. Hold one probe on one of the hot buss bars and the other probe on the neutral bar. The neutral bar has several white wires attached to it. Confirm that no voltage is present.

Feed the cable into the main panel through an existing opening. A 20-amp circuit will require 12-gauge or heavier wire. A 240-volt circuit will require 12-2 cable with ground and a 240-volt circuit will require 12-3 with ground cable. The 12-3 cable is only required if the 240-volt circuit requires a neutral wire.

Use the utility knife to cut the outer jacket of the cable 12 inches from the end. Cut off the jacket and packing material. Strip the insulation 1/2-inch from the ends of the wires using the wire stripper.

Tilt the breaker at a 45-degree angle and hook the outside edge onto the support buss. Lower the breaker until it snaps into position. The 120-volt breaker will utilize one breaker space and the 240-volt breaker will require two breaker spaces.

Loosen the terminal screws on the breaker and Insert the black or red wire under the terminal. Tighten the terminal screw to hold the wire securely. There will be two black or red wires for the 240-volt breaker and one for the 120-volt breaker.

Break off the tab or tabs, as required, on the panel cover where you installed the new breaker, so the cover will fit flush on the panel. Hold the cover in place, and insert and tighten the mounting screws. Turn the main breaker on. Do not turn on the new breaker.

Feed the cable through the walls, attic or basement crawl space as appropriate, and route it to where the receptacle will be located.

Punch a hole in the wall with a screwdriver at the desired receptacle location. Feed the cable out through the wall and cut the outer jacket back six inches. Strip 1/2-inch of insulation from the ends of the wires.

Push the wires through the back of the electrical box and secure the box to the wall. Loosen the terminal screws on the receptacle. Wrap the green wire around the green screw and tighten securely. If there is a silver terminal wrap the white wire around the silver screw, and tighten securely. Repeat this for the remaining red or black wires. Use one red or black wire for a 120-volt receptacle and two for a 240-volt receptacle.

Push the excess wires into the back of the electrical box and secure the receptacle to the box. Put the cover plate over the receptacle and screw into position. Turn on the new breaker at the main panel and use the voltmeter to ensure that the circuit is on.