All breakers are designed to prevent the wire in your home or business becoming overloaded. All breakers are designed to automatically turn off if the circuit is carrying too much load or if there is a short circuit present. Arc Fault breakers have the additional ability to sense arcing in a circuit. Arcing is the sparking you might see between 2 damaged conductors, and is a fire hazard as this arcing is extremely hot. An arc welder uses electrical arcing to weld steel. A regular breaker may not sense that because it does not always create the load needed to trip the breaker, but an Arc Fault breaker will sense it and shut the circuit down before it can cause a fire. These devices are designed and required to be tested on a monthly basis to ensure proper and safe operation.