A method detects a glowing contact in a power circuit. The method applies at least two different resistance values across the power circuit and responsively senses at least two voltages across the power circuit. Each of the at least two voltages correspond to one of the at least two different resistance values. Then, the method determines if a number of changes in the sensed at least two voltages with respect to a number of changes in the at least two different resistance values is linear within a predetermined range or if a change in two of the sensed at least two voltages does not increase with a decrease in two of the at least two different resistance values and, otherwise, responsively generates at least one of a trip signal and an alarm signal corresponding to detecting the glowing contact in the power circuit.