A method of tripping a circuit breaker including sampling an AC line voltage at regular intervals during a first time period to generate a plurality of AC line voltage samples. Each sample of the set of AC line voltage samples is summed to generate a voltage area value. A controller determines whether the voltage area value exceeds a threshold. In response to the voltage area value exceeding the threshold, an amount determined as a function of the voltage area value is added to a count value. The circuit breaker is caused to trip in response to the count value equaling or exceeding a maximum count value.An improper line-to-neutral voltage can be detected by monitoring the line-to-neutral voltage and comparing it to a function such as a trip curve. Thus, components downstream from a circuit breaker, as well as the circuit breaker itself, can be protected from prolonged exposure to improper voltages, which can lead to component failure.