A system and method for monitoring the continuity of a ground conductor in a power transmission system. A plurality of power transmission cables extend between a power source and a load and include a ground conductor extending between the source and the load. The monitoring system includes a transmitter for transmitting a signal within the audio range over the ground conductor. A receiver receives the signal from the transmitter over the ground conductor. The receiver has associated therewith an alarm device and/or a circuit breaker. In response to the absence of the signal at the receiver which would correspond to an interruption in the ground conductor, the circuit breaker is opened to disconnect the power source from the load. Both the receiver and transmitter are coupled to the ground conductor through closed inductive systems comprising toroids.