Potential Criteria for the Cathodic Protection Of Lead Cable Sheath★

Abstract

Abstract A report is made of the study of the static and dynamic potentials of lead cable sheath in 48 soils from various sections of the United States. Soils have been selected as representative of those actually in contact with cable sheaths. Anodic and cathodic polarization curves in representative soils, using a null bridge technique, are given to illustrate the potential changes accompanying corrosion and cathodic protection. Data indicate that significant corrosion may occur at potentials near the static potential of the lead sheath for that particular soil. To achieve cathodic protection it appears that the lead sheath should be polarized about 100 millivolts more negative than its static potential in the particular soil. In most soils this would require polarization to about 700 millivolts negative to the saturated copper-copper sulfate, electrode. 5.2.4