Why Is My Arc Fault Circuit Breaker Tripping?

An arc fault circuit interrupter (AFCI) plays an important safety role in your house: It helps detect dangerous electrical arcs that can cause sparks and, potentially, a fire. When an AFCI notices arcing, it automatically switches off in order to shut down the circuit. But arc fault breaker tripping can be caused by other issues too, like plugging in too many appliances at once. Here’s how to tell why your arc fault circuit breaker keeps tripping, and when it’s time to call an electrician.

How to Troubleshoot a Tripped AFCI Breaker

The best way to figure out what is tripping your arc fault breaker is to isolate the issue by taking all the following measures.

Unplug Everything in the Circuit

The first step to uncovering the problem with your tripping AFCI breaker is to unplug all devices from the receptacle. Then, turn off the lights and inspect whether the breaker still trips after it’s reset. 

If that step resolves the problem, the issue is likely a faculty appliance that’s overloading the circuit or is incompatible with it.

Plug In and Turn On One Device at a Time 

Another troubleshooting step is to unplug and replug in one device at a time to determine what outlet or light is tripping the breaker. Inspect everything for signs of frayed wiring or other visible issues.

Check for Faulty or Broken Pieces

Check to see if each device has a faulty or broken cord, if it's plugged in all the way, and if it’s compatible with the AFCI breaker. Inspect all connections for signs of visible damage.

Reduce Strain on Circuit

Reset the circuit breaker or put less strain on the circuit. You may need to plug your power tool or vacuum into an outlet on a different circuit to lessen the electric load.

Once you isolate the issue, you can determine if you can fix it yourself, need to replace a device, or hire an electrician to help. If you don’t find the issue in an appliance, electrical device, or overloaded circuit, the problem is likely related to wiring. Call an electrician who can safely look at your junction boxes, outlets, switches, and wiring to see what the issue might be. 

The electrician will also look at your AFCI breaker to see if you need to replace it, although the breaker itself isn't often the problem. You can avoid the cost of a new circuit breaker box if you have an electrician who looks thoroughly into the problem first.

Reasons Why Your AFCI Breaker May Be Tripping

Unlike other circuit breakers, an arc fault circuit interrupter (AFCI), or arc fault breaker, helps detect and limit hazardous sparking. You’ll know your AFCI breaker trips when outlets on that circuit no longer work. Your breaker can malfunction due to a frayed electrical cord, an incompatible device or appliance, improper wiring, or something as simple as a nail put through a wire. 

Your arc fault breaker tripping signifies that something needs to be repaired or removed from the circuit. To keep you, your family, and your home safe from any possible electrical fire, find out why your arc fault breaker keeps tripping, learn how to find and fix the issue, and figure out when it’s best to call an electrician.

1. Incompatible Appliances or Devices

If you have older appliances or devices that produce a certain mechanical arc pattern, they might be incompatible with your AFCI breaker. If it’s a well-loved appliance like your grandma’s space heater or you notice the device doesn’t work as well as it used to, it may be time to replace it. Appliances that could trip your breaker include vacuum cleaners, printers, power tools, treadmills, or even fluorescent lights. Most newly engineered devices will work with your arc circuit breaker, but be mindful of older appliances that might trip the breaker.

2. Faulty Appliances or Devices

Beyond incompatibility, you might have a faulty device, such as a lamp with a damaged cord. Check to see if your devices are plugged into the socket all the way, as lack of full contact can generate a spark that trips your breaker.

3. Damaged Wiring

Your arc fault breaker tripping could be due to something as minor as hanging a picture on the wall and unknowingly putting a nail through a wire—or even a rat chewing at a wire inside your wall. This can cause sparking to happen, which then trips the breaker.

4. Faulty Wiring

You might have issues with your wiring, whether it’s loose, exposed, or an outlet that’s wired improperly. Improper wiring or wiring insulation can lead to ground faults and short circuits. These problems are usually best detected and fixed by an electrician near you.

5. Electrical Overload

Photo: Reimar / Adobe Stock

Like any other breaker, an arc circuit breaker can trip if there’s too much electrical usage on a single circuit and it overheats the wires. Perhaps you plugged in a power tool on the same circuit with your washer, dryer, and microwave, and it’s too much for the circuit to handle. 

Wires can manage a certain amount of amperage or current, but it's not safe once you exceed that level. Your breaker will trip, so stop overloading the circuit, as it could cause an electrical fire. Instead, ask an electrician to add an additional circuit to separate some of your appliances.

6. Overheating Breaker

If your breaker has poor contacts or connections, it might overheat and trip. If left unresolved, an overheated breaker could start an electrical fire.

What Does an AFCI Do?

An AFCI breaker has a built-in monitoring system that continuously checks for potentially dangerous arcing. If the AFCI detects arcing, it automatically shuts off, thus adding an extra layer of protection against electrical fires.