Circuit Breaker Keeps Tripping
When it trips tells you why. Instantly, under load, or at random.
Compiled by DIY Repair Guide · reviewed 2026-09-05 ·how we research these
The timing of the trip tells you the cause. A circuit breaker that goes instantly with nothing plugged in has a short circuit. One that goes twenty minutes into vacuuming has an overload. One that goes at no predictable moment is usually a failing breaker or an arc fault.
Every trip reports a real condition, so the job is to read the report rather than keep pushing the handle back. Those three patterns have completely different fixes, and the sections below take them in turn.
Start Here: When Does It Trip?
Before you investigate anything else, establish which of three patterns you have. It narrows the cause immediately.
Overload. Trips Under Load, and the Common One
If the breaker holds fine until you switch on the space heater, or trips a few minutes into using the vacuum, you are simply asking for more current than the circuit is rated to carry. This is by far the most frequent cause, and the only one most people can resolve themselves.
A 15-amp circuit carries 1,800 watts flat out, and a 20-amp carries 2,400. For anything running continuously, plan against 80 percent of that, 1,440 W and 1,920 W. Two 1,500-watt heaters on one circuit is 25 amps, and no breaker will tolerate that.
- Find what shares the circuit. Switch the breaker off and walk the house noting every dead outlet and light. It is rarely just the room you were standing in.
- Move the biggest load elsewhere, ideally onto a circuit that is not already carrying much.
- Stop using extension leads for heaters. High-draw appliances belong in a wall outlet.
- If you keep hitting the limit, the real answer is another circuit, which is electrician work.
| Appliance | Typical watts | Amps at 120 V |
|---|---|---|
| Space heater | 1,500 W | 12.5 A |
| Hair dryer | 1,200–1,875 W | 10–15.6 A, enough to trip a 15 A circuit alone |
| Microwave | 1,000–1,500 W | 8–12 A |
| Kettle or toaster | 1,200–1,500 W | 10–12.5 A |
| Vacuum cleaner | 1,000–1,400 W | 8–12 A |
| Window air conditioner | 900–1,500 W | 7.5–12.5 A |
| Shop vac or circular saw | 1,000–1,800 W | 8–15 A |
Never fit a bigger breaker to stop the tripping. The breaker is sized to protect the wire. A 20-amp breaker on 14-gauge wire lets the cable heat past its rating without ever tripping, which is how electrical fires start.
Short Circuit. Trips Instantly, Even with Nothing Plugged in
If the breaker will not stay on at all, or goes the moment you reset it with every device unplugged, current is finding a path it should not have. A hot conductor is touching a neutral, or a damaged cable is shorting inside a wall or a device.
Signs that point this way: a scorch mark or black smudge around an outlet, a smell of burnt plastic, a buzzing or crackling from a switch, or a breaker handle that feels hot. Sometimes the fault sits in one appliance. Unplug everything on the circuit, reset, and add devices back one at a time. If it holds with everything unplugged, the last thing you plug in before it trips is your culprit.
If it trips with the circuit completely empty, the fault is in the fixed wiring. That is an electrician, today.
Ground Faults Usually Mean a GFCI and Usually Mean Water
A ground fault is current escaping to earth rather than returning along the neutral. Ground-fault circuit interrupter (GFCI) outlets and breakers watch for exactly this and cut in milliseconds, because that leaking current can just as easily travel through a person.
These are concentrated where water is: bathrooms, kitchens, garages, basements, outdoor receptacles. A GFCI that trips after rain, or when a particular appliance runs, is usually finding real moisture. In an outdoor box, a damaged lead, or an appliance that has taken in water.
Test the device itself first. Press Test, it should trip, then Reset. A GFCI that will not trip on test, or will not reset with nothing connected, has failed and needs replacing. They wear out, and ten to fifteen years is a normal life.
Arc Fault. the Modern Nuisance Trip
arc-fault circuit interrupter (AFCI) breakers are required on most living-area circuits under current code. They look for the electrical signature of arcing, the small sputtering discharge that precedes many fires, and they are considerably more sensitive than a standard breaker.
They also nuisance-trip on things that are not dangerous. Older vacuum motors, some LED drivers, treadmills and certain power tools generate noise that an AFCI can read as an arc. If a specific appliance reliably trips an AFCI and nothing else does, that is the likely explanation. It still deserves a look, because a genuine arc fault behaves identically from the outside.
Resetting once to see if it holds is normal troubleshooting on a suspected overload. If it trips again immediately with nothing plugged in, stop. You are re-energising a short circuit. Resetting repeatedly over days, or taping the handle down, overrides a fire protection device while the condition that triggered it continues.
A Breaker That Has Simply Worn Out
Breakers are mechanical and they age. One that trips at well under its rated load, feels loose or hot, will not reset firmly, or has become markedly more sensitive over a few months may have failed internally. Thermal elements weaken with each trip, so a breaker that has protected a circuit through years of overloads gradually becomes a breaker that trips at ten amps instead of fifteen.
Replacement is inexpensive as a part and is panel work. Live busbars sit inches from your hands even with the main off. This is standard electrician work and not a sensible first DIY project.
What to Do, in Order
A sequence that resolves the common cases without guesswork.
- Note the timing. Instant, under load, or random. That is your diagnosis.
- Unplug everything on the circuit and reset. Holds? Overload or a faulty appliance. Trips anyway? Fixed wiring fault.
- Add devices back one at a time, giving each a few minutes.
- Total the wattage of whatever runs together and compare against 1,440 W (15 A) or 1,920 W (20 A).
- Redistribute the load or stop running the heavy items simultaneously.
- Call an electrician for: any burning smell or scorch mark, a hot breaker or outlet, tripping with the circuit empty, or repeated trips you cannot account for.
Common questions
Why does my breaker trip when nothing is plugged in?
That points to a fault in the fixed wiring or in the breaker itself rather than to a load problem. Most often a short circuit somewhere in the cable or a device wired in permanently. It is not a DIY diagnosis. Call an electrician.
Is it dangerous to keep resetting a tripped breaker?
Resetting once or twice to test is normal. Doing it repeatedly is not, because you are re-energising a circuit that has already reported a fault. If it trips a second time without an obvious overload you have removed, stop and investigate.
Can a bad appliance trip a breaker?
Frequently. A failing motor, a damaged cord or an appliance that has taken in water can draw excess current or leak to ground. Unplug everything and reintroduce items one at a time. The one that trips it is the one to retire.
Why does my breaker trip only when it rains?
Almost always moisture reaching an outdoor receptacle, a light fixture or a damaged cable. It usually shows up on a GFCI because that is what a ground fault looks like. Check outdoor boxes for missing or cracked covers.
Can I just install a bigger breaker?
No. The breaker protects the wire. It does not protect the appliance. Fitting a larger one lets the cable carry more current than it is rated for, and the wire can overheat inside a wall without the breaker ever tripping.