The biggest challenges that we electricians have faced during this introduction of new technology has been nuisance tripping of any product that has a motor with brushes. For example, when you peer into a power drill while it’s running, you can see the sparks created by the brushes. Sparking and arcing are exactly what the AFCI breaker is looking for, and so it will interrupt the circuit power.

The engineers who have designed these AFCI Breakers found that motors, like the ones found in the power drill, vacuums and treadmills produce a rhythmic, mechanical arc pattern. So they program these patterns into the digital “brains” of the AFCI breaker so it won’t trip as often on these common household items.

But at times, older products with motors will cause the AFCI breaker to trip. This is because the brushes wear down on these older motors, which causes the arc pattern to become irregular and not as rhythmic as when the motor was new. This causes AFCI to detect this as an arc and trip the circuit for safety.

While this type of nuisance tripping can be frustrating, the good news is that the AFCI breakers are being continually improved.