A new impedance-based active earth fault location algorithm for utilisation in a high impedance-earthed distribution system is presented. This method which involves a simple insulated gate bipolar transistor (IGBT) switch action can be applied in real-time to fault location, because of its relatively low processing requirements. In this study, the method is explored through simulation and validated using experimental tests. The experimental tests were applied to a cable distribution system with both linear and non-linear loads. The simulations were then extended to a six-zone marine distribution system.