In a method for cathodically protecting and/or passivating a metal section in an ionically conductive material such as steel reinforcement in concrete or mortar, an impressed current or sacrificial anode communicates ionic current to the metal section and a storage component of electrical energy which can be a cell, battery or capacitor is provided as a component of the anode. A current limiter is provided which prevents excess current draining the supply. This can be a semi-conductive device such as a transistor or diode is connected in the path from the anode to the metal section to limit the cathodic protection current to a value of the order of 1 milliamp. When a diode or similar device is used the current can be limited to the reverse leakage current of the diode.