Series arcing in wiring is a potentially catastrophic situation that has proven to be difficult to detect reliably with existing methods. This invention allows for the quick and accurate detection of series arcing in an electrical circuit. The method works with AC or DC power sources, and at any voltage or current level. This method will also detect high resistance in a circuit, which is another indicator of a potentially hazardous fault condition. The method compares the voltage at each end of a conductor, and will declare a fault when this voltage exceeds the minimum voltage required to sustain arcing.