Methods for determining the value of the power factor for inductive low-voltage (1000 V ac and lower) test circuits are provided. These methods are used in determining the power factor during short-circuit current tests in high-power laboratories. It is preferred that these methods be used during short-circuit current testing. Alternatively, other methods (including use of computerized or digital techniques) may be used, but the method used shall have been validated as producing results equivalent to those obtained using the methods in this guide. The methods described are intended for use in low-voltage test circuits (under 1000 V ac) but may also be used for higher voltages.