How to Replace a Circuit Breaker

How to Replace a Circuit Breaker

1. Turn the Main Power Off

   Locate the main circuit breaker and flip it to the OFF position. This may now put you in the dark, so make sure you have a flashlight handy. All branch circuits in the panel will now be shut off.

   It's best to wear safety glasses when working, stand to the side of the service panel when turning a circuit breaker on or off, and turn your eyes away from the panel until the transition is made. Although the possibility is remote, there is a chance of explosion in a circuit breaker panel, and standing to the side and looking away is a safety measure designed to protect vision.

   Warning

   The main breaker shuts off power to the branch circuit breakers, but it does not affect the incoming power service lines or the terminals they connect to (called service lugs) in the service panel. These components remain live—carrying deadly voltage—unless the power company shuts off your service. Do not touch the service lugs or the bare wire of the incoming service lines at any time.

2. Remove the Breaker Panel Cover Plate

   Remove the screws holding the panel cover plate on. It's best to leave the middle two screws in place until last, removing the corner screws first. Loosen the two remaining screws while holding the cover to keep it from falling to the ground. Be very careful not to let the cover tip into the panel as you remove it and set it aside.

3. Remove the Old Circuit Breaker

   Now that the cover is off, you can start the replacement process. Turn off the new breaker by flipping its reset lever to the OFF position. 

   If the black insulated circuit wire connected to the breaker is folded tightly along the sides of the panel, carefully extend it out from the panel, being careful not to touch any other wires or the panel itself.

   Carefully grasp the edge of the old breaker at the inner center part of the panel and pivot it out towards the outer side of the panel. The breaker should snap free and pull out from the panel. Be very careful not to touch the metal bus bar where the breaker was attached. Once it's free of the panel, the breaker is guaranteed to be inactive because it is no longer in physical contact with either of the hot bus bars.

4. Disconnect the Wires

   Remove the black circuit wire attached to the breaker by unscrewing the screw terminal gripping the wire. (If replacing a 240-volt breaker, it will have two hot wires, usually red and black.)

   If you are replacing an AFCI or GFCI circuit breaker, it will also have a neutral circuit wire connection on the circuit breaker, as well as a coiled white pigtail wire that runs to the neutral bus bar in the panel. Disconnect these wires. The bus bar wire can be disconnected by loosening the set screw, and extracting the wire from its lug on the bus bar.

5. Attach the Wires to the New Circuit Breaker

   Check the breaker reset lever on the new breaker is in the OFF position before installing it.

   Attach the black circuit wire to the new breaker by inserting the bare end of the wire under the screw terminal on the breaker and tightening the screw. This terminal may be labeled LOAD or LOAD POWER.

   If you are replacing an AFCI or GFCI (or AFCI/GFCI combination breaker), connect the white neutral circuit wire to the corresponding screw terminal on the breaker. This terminal may be marked NEUTRAL or LOAD NEUTRAL. Connect the coiled white wire attached to the circuit breaker to a screw terminal on the neutral bus bar in the panel. Many new GFCI and AFCI breakers have "plug-on" neutrals so the coiled wire is no longer needed, and the panel will be made for this configuration.
   

6. Insert the Breaker

   Hook the back of the new breaker into the back holder clip on the breaker panel, and push the breaker forward into place. This could require a bit of force. Make sure the breaker lines up with the bus bar as you install it. You should feel a click as the breaker snaps into place onto the hot bus bar.

   Tuck the excess wire into the panel, neatly folding it into the empty space along the side of the panel. Again, be careful not to touch other wires or metal parts on the panel.

7. Replace the Panel and Turn the Power On

   First, replace the service panel cover and its screws. Then, flip the toggle levers on all individual circuit breakers to the OFF position before turning the main breaker on. This will prevent a sudden high power demand on the electrical service when the main circuit breaker is activated.

   With all circuits off, flip the lever on the main circuit breaker to the ON position. Now, flip each individual branch circuit breaker to the ON position, one at a time.

   Make sure the circuit fed by the new circuit breaker is operating correctly by testing each of the fixtures and outlets powered by the circuit.

When to Replace Circuit Breakers

A circuit breaker tripping often is one of the main signs a replacement is needed. Some of the other warnings to look out for include buzzing sounds, corroded or frayed wires, flickering lights, burning odors, and the circuit breaker and outlets around the home feeling hot to the touch.

You may also want to consider replacing your circuit breaker if it's more than 25 years old, or if you calculate your amperage capacity needs are increasing due to new appliances or installations.

When to Call a Professional

Replacing a circuit breaker is not inherently difficult, but it can cause nervousness, even for DIYers with advanced skills, since it involves work at the main service panel with the safety cover removed. where the potential for fatal shock always is present.

If you are not fully confident of your skills, or if the circuit breaker panel seems old or unusual, it is best to call a professional electrician to make this repair. A professional will also know the National Electrical Code, and understand the requirements for installing both AFCI (arc-fault circuit interrupter) and GFCI (ground-fault circuit interrupter) breakers.