A current detector and indicator unit are coupled to a shore power cord for monitoring for corrosion-causing galvanic current on the ground wire of the power cord. A current transducer coupled to the ground wire senses current and provides a signal corresponding to the magnitude of the sensed current to a microcontroller. The microcontroller compares the magnitude of the current signal to one or more predetermined thresholds and outputs signals to an indicator unit to display the level of galvanic activity accordingly.