How to Add a New Circuit Breaker

For some handymen who have electrical experience and who take important precautions, adding a new circuit breaker can be accomplished without injury from electrical circuits. If you are one of those who have this experience and want to face the challenge of adding an electrical circuit breaker, here are a few steps you'll want to take.

Step 1 - Locate Unused Breaker Switches

Using a screwdriver, removing screws from your breaker cabinet cover and do a visual inspection of the breaker switches. You'll be looking for a breaker switch that is not connected to any circuit wires. If all switches are in use, you can buy a new one at a hardware store that sells electrical supplies and accessories.

Step 2 - Install Electrical Wire

Connect the far end of the romex to the switch or receptacle to which your new breaker will be connected.

Step 3 - Secure the Romex To The Cabinet

Visually locate your breaker box main switch and the service cable coming into the breaker cabinet. Turn off the circuit breaker you're going to install. Loosen the clip screw that connects the wire to the breaker switch. Now, using a hammer and screwdriver, make an entrance hole in the cabinet by punching out the knockout at the cabinet side. Secure the cable connector by positioning it in the knockout hole. Be sure the clamp screws are outside the panel. Now, on the cable connector you'll find a clamp with screws. Loosen the clamp's screws enough that you can push the romex end through it.

Step 4 - Prepare the Romex for Connecting to the Circuit Breaker

Use your wire stripper to remove sheathing from the end of the romex that will be inside the breaker cabinet. Insert the romex end through the cable connector until it forms a loop. The bend of this loop should reach the bottom of the panel, and the loop end should reach the circuit breaker. Using your marker, place a mark on the romex, just inside the cable connector.

Step 5 - Secure the Romex Inside the Panel

Pull the romex out of the panel again and remove its sheathing, beginning at the mark you made. Feed the romex back through the cable clamp and tighten the clamp on the part of the romex that still has sheathing on it.

Step 6 - Attach the Romex Wires to the New Circuit Breaker   

Strip ¾ inch of the insulation from the romex wires and insert the bared white wire into an available hole in the neutral bus. Tighten the screw that holds the white wire in place in the bus. Now, connect the copper wire to the grounding bus, feed the black wire into the circuit breaker's clamp and tight the clamp screw.

Step 7 - Restore Power to the Circuit Breaker

After replacing the cabinet cover, make sure all circuit breakers are turned off, then turn the main breaker on. One at a time, flip each circuit breaker back to the "on" position.