Cathodic protection is a method of protecting the walls of jetty steel piles against corrosion.
In principle, there are two methods for cathodic protection of jetty piles, sacrificial anode and impressed current. The sacrificial anode cathodic protection method has limited coverage, while the impressed current covers the entire length of the subsea pile.
With the sacrificial anode method, an anode, mostly aluminum or zinc, is welded to each pile. This cathodic protection method works independently for each pile and has no effect on other piles in the area. The anode material corrodes under the influence of the steel and must eventually be replaced.
For larger structures, like most Jetties, sacrificial anodes cannot economically deliver enough current to provide complete protection. With the impressed current cathodic protection method, a transformation rectifier unit is installed and connected with cables to the piles and to an external anode. With this method all the jetty piles in the area needs to be bounded with each other. In this case, all jetty piles of the structure are connected and form one electrical unit. Since the theoretical life of an ICCP system is generally long, only simple maintenance is required. Owners can easily check that the system is working properly on a daily basis without any onerous checks.
