In the impressed current cathodic protection systems (active protection), the current is supplied by a DC generator, the positive pole is connected to the anode and the negative one to the structure to be protected, the circuit is closed through the electrolyte.

The components of an impressed current protection system are: anode, the DC source and current-carrying wires. The current source is usually a transformer-rectifier fed by DC, anodes can be of different materials and shapes depending on use and their consumption rate is negligible compared to the sacrificial ones. Finally, a suitable automatic control system allows to optimize the functionality of the system keeping under constant observation the parameters.