Cathodic protection

The paper deals with the theory and practice of the method of corrosion mitigation known as cathodic protection. The nature of electrochemical corrosion and the fundamentals of cathodic protection are briefly discussed. This is followed by a survey of the two practical methods of achieving cathodic protection¿sacrificial anodes and power-impressed currents. Since the method of measuring potentials is not that of normal electrical practice, the subject is considered in some detail together with the method of measuring soil resistivity. The possibility of adversely affecting other buried services is noted, and current practice in carrying out potential tests with the owners of such services, and of bonding to eliminate adverse effects, is considered. Finally the application of cathodic protection and the general economics affecting its use are discussed.