Patent ID: 7791346

Claim:
A device that is temporarily connected to and tests an electrical power branch circuit comprising hot, neutral and protective ground conductors and that carries alternating current (AC), the device comprising: circuitry that measures the voltage and impedance of the branch circuit, and in response determines a short-circuit current that the branch circuit is capable of carrying, and a ground-fault current that the branch circuit is capable of carrying; circuitry that, based on at least one of the determined short-circuit current and the determined ground-fault current, applies at least one of a short-circuit current and a ground-fault current to the electrical power branch circuit; in which the circuitry that applies current to the electrical power branch circuit applies the current for a controlled duration; and circuitry for determining the zero crossing point of the AC waveform, in which the current is applied beginning at a point related to the determined zero crossing point.