Circuit breakers are switches that turn off the flow of electricity to a circuit when an overload or other type of fault occurs. The breaker itself is quite durable and rarely the cause of a tripped circuit. When troubleshooting a problem circuit, begin by checking for overloads, then for shorts, and finally examine the breaker itself.
Make sure you understand how breakers work before trying to fix them. Circuit breakers are heat-sensing switches that use a bimetal strip and a spring to close a circuit, allowing current to flow. Faults in circuits cause heat, which, in turn, causes the strip to bend. This releases a lever that opens the circuit and cuts off the power until you reset it.
Begin troubleshooting at the end of the circuit, not at the breaker. The breaker itself is rarely the source of the problem, unless it has mechanically failed--an unusual occurrence.
Check for an overloaded circuit. The usual culprit is an overloaded circuit with too many appliances or fixtures drawing too much power. Most household circuits operate at 120 volts and 15 amps, and are capable of safely drawing 1,440 watts of power. If the total wattage on the circuit greatly exceeds this, the breaker will trip. Add the total amount of wattage from appliances and fixtures on the circuit to make sure it does not exceed the circuit’s rating. Most appliances have their wattage printed on them.
Check for short circuits by unplugging the fixtures or appliances individually and observing the results. Overheated wires in light fixtures are frequent culprits. If the appliances check out, examine each power receptacle and light switch on the circuit for loose or worn wires. Use a neon receptacle analyzer to detect faults in power outlets. If there are no shorts in the switches or outlets, the problem is either the breaker or the wiring behind the walls.
Replace the breaker before calling an electrician to check the wires. Breakers snap onto a hot bus bar, so make sure to kill power to the service panel before pulling the breaker off the bar. Disconnect the black wire leading to the old breaker and attach it to the new breaker. Snap the new breaker into place.
Call an electrician if checking for overloads and shorts and replacing the breaker does not solve the problem.