Described is a cable rejuvenation apparatus for a cable used in a subsea environment. The apparatus applies a bias signal to a conducting element of the cable, the bias signal being selected to improve the insulation properties of the cable. The bias signal is generated by a bias signal generator that includes a voltage source that generates a bias voltage having a time varying component. The bias voltage promotes an electrochemical reaction between the conducting element and the salt containing liquid of the subsea environment resulting in the formation of a barrier material at the fault location restricting further leakage current flow and enhancing the insulation resistance of the cable. The bias signal is a voltage selected such that the electrochemical reaction promoted by the bias voltage maintains the presence of the barrier material at the fault location.