Abstract: An apparatus for reducing the difference in electrical potential between two electrical conducting objects located a distance from each other in an electrical conducting medium includes an equalizing cable with a predetermined resistance valve detachably connected between the two objects. A current detector is coupled in series with the equalizing cable between the two objects and generates a first output voltage with a value dependent on the equalizing current in the equalizing cable. An instrument lead is also detachably connected between the objects. A voltage detector connected in series with the instrument lead between the objects senses the potential difference between the objects and generates a second output voltage having a value dependent on the sensed potential difference.