Isolation circuitry

Isolation circuitry for automatically disconnecting a load from a source upon detecting a short and for automatically reconnecting the load to the source after the short circuit clears. The isolation circuitry includes a first node connected to a second node via a first transmission path, and a third node connected to a fourth node via a second transmission path maintained at a different voltage than the first transmission path. There is a switch between the nodes on the first transmission path, and a sensing circuit that is connected between the first and second transmission paths. The sensing circuit includes a current generator that induces a fault indicating current into a load between the first and second transmission paths and monitors the fault indicating current for an increase over a threshold defined by an operating voltage setting circuit when the load impedance falls below a lower limit indicating a short circuit. The sensing circuit provides a control signal to open the switch if a short circuit is detected and to close the switch if a short circuit is not detected.