A device and method for testing an electrical power branch circuit that includes hot, neutral and protective ground conductors and that carries alternating current. The device includes circuitry for determining the total available short-circuit current that can be carried by the neutral conductor, circuitry for determining the total available ground-fault current that can be carried by the protective ground conductor, and circuitry that, based on at least one of the determined short-circuit current and the determined ground-fault current, applies a short-circuit or ground-fault current to the electrical power branch circuit.