For reducing pollution of ports, since they are frequently very close to residential districts, the docked ships are required to shut down on board generators. There are some solutions in development focused on pollution reduction, such as permissible fuels for docked ship, “scrubbers”, the cold ironing. The cold ironing or shore to ship consists in supplying the ships by the shore electrical systems. The paper deals with a short outline on the cold ironing system and on its usual grounding system. To exploit safety of personnel, protection of equipment and protection against corrosion problems, the authors suggest adopting the TN-island system for the cold ironing.