Check the faulty circuit breaker to determine the amperage. It will usually be either 15 amps, 20 amps or 30 amps. Make sure your replacement breaker is of the same amperage and has the same number of poles (usually single pole or double pole) as the old one.
Open the breaker box and shut off the central switch controlling power to the entire house. Then turn the faulty breaker off.
Use a voltmeter or a multimeter to test the faulty switch. There should be no power running through it while you work.
Detach the faulty switch from its housing. In most modern circuit boxes, the switch will just pop right out. With older boxes, it may be connected with screws that you can loosen with a screwdriver. Be careful not to pull too hard on any of the wires connecting it.
Unscrew the terminal screws connecting the circuit to the wiring, and pull the wiring free. Keep careful track of which wire is attached to which screw. Label them with masking tape if it will help you remember.
Loosen the terminal screws in the new circuit breaker, but don't remove them entirely. Then connect the wiring to them in the same positions as the faulty breaker and tighten the terminal screws until the wires are secure.
Slip the new breaker into position, either by snapping it in place or screwing it back into the housing as appropriate.
Turn the main switch back on, restoring power to the house, then turn the new breaker on. Check it with the voltmeter or multimeter to ensure that electricity is running through it, then replace the panel frame on the breaker box and close the panel door securely.
Things You Will Need
- Screwdriver Voltmeter or multimeter New circuit breaker Masking tape Marker
- The new breaker should always be in the "off" position until it is properly installed and ready to be turned on.