Why Does My Circuit Breaker Keep Tripping?

Find out what was running when it tripped.

CPSC’s guide to home wiring hazards advises checking which breaker has tripped and which appliances lost power before resetting it. Then look up the watt ratings on those appliances’ labels and add them together. If an appliance repeatedly trips the breaker, or has shocked someone, unplug it and have it repaired or replaced.

Most repeated trips on one circuit are simply too much on one circuit.

CPSC’s appliance power budget keeps the total on a branch circuit below 1,500 or 2,000 watts. Those figures sit under the circuit’s capacity: at 120 volts, a 15-amp circuit carries 1,800 watts and a 20-amp circuit 2,400. A 1,500-watt space heater and a 1,200-watt microwave on the same kitchen circuit add to 2,700 watts, which no ordinary household circuit is meant to carry.

The fix CPSC gives is to move an appliance to a different circuit with less on it, and if that is not possible, to get help from a qualified electrician. Heating appliances deserve special care because they draw the most.

Extension cords are not wiring.

The U.S. Fire Administration advises plugging major appliances — refrigerators, stoves, washers, and dryers — directly into a wall outlet, never through an extension cord, which can overheat and start a fire. Do not overload outlets or power strips, use power strips with internal overload protection, replace worn or damaged cords, keep cords out from under rugs, and replace outlets that no longer hold plugs snugly.

These point to the wiring itself.

• Lights that dim or flicker
• Arcs, sparks, or flashes anywhere in the system
• Sizzling or buzzing sounds
• Switch plates, outlet covers, cords, or plugs that are hot rather than slightly warm
• A breaker that trips immediately on reset with nothing plugged in

CPSC lists the first four as warning signs of wiring problems. Any of them — or a burning smell — means turn the circuit off and call a qualified electrician. Do not replace a breaker with a larger one to stop the tripping; the breaker is sized to the wire, and a larger one lets the wire overheat.

The same rule, with a replacement part.

CPSC’s advice is to correct the overload before replacing a blown fuse, and to use a 15-ampere fuse unless you are certain the circuit is wired for 20 amperes. A fuse larger than the circuit is designed for removes the protection entirely.