(a) Except for buried piping at compressor, regulator, and measuring stations, each buried or submerged transmission line, or distribution main to be operated at a pressure of 125 psig (862 kPa) or more in a Class 3 or 4 location, installed before August 1, 1971, that has an effective external coating must be cathodically protected along the entire area that is effectively coated. For the purposes of this Part, a pipeline does not have an effective external coating if its cathodic protection current requirements are substantially the same as if it were bare. The operator shall make tests to determine the cathodic protection current requirements.
(b) Except for cast iron or ductile iron, each of the following buried or submerged pipelines installed before August 1, 1971, must be cathodically protected or replaced in the areas in which active corrosion is found:
(1) bare or ineffectively coated transmission lines;
(2) bare or coated pipes at compressor, regulator, and measuring stations; or
(3) bare or coated distribution lines, except coated distribution mains to be operated at a pressure of 125 psig (862 kPa) or more in a Class 3 or 4 location.