Methods and electric circuit arrangements for protection of metallic components from corrosion via stray currents

Methods and electric circuit arrangements for protecting metallic components in an electrolytic medium from corrosion due to direct-current (DC) stray current (Is) from a power supply system. The DC stray current may be jointly registered as a total sum current across all active conductors together with the protective conductor of the power supply system by a DC total differential-current sensor. Alternatively, a combined DC differential-current sensor is switchable by a switching device, a differential current being registered across all active conductors or the DC stray current being registered as a total differential current across all active conductors and the protective conductor. Alternatively, a differential current may be registered across all active conductors by a DC current sensor at the protective conductor and the DC stray current computed by forming differences of the differential current registered by the differential-current transformer and of the protective conductor registered by the DC current sensor.