This European Standard is applicable to buried cathodically protected metallic structures that are influenced by a.c. traction systems and/or a.c. power lines. In this document, a buried pipeline (or structure) is a buried or immersed pipeline (or structure), as defined in EN 12954. In the presence of a.c. interference, the criteria given in EN 12954, Table 1, are not sufficient to demonstrate that the steel is being protected against corrosion. This European Standard provides limits, measurements procedures, mitigation measures and information to deal with long term a.c. interference and the evaluation of a.c. corrosion likelihood. This standard deals with possible a.c. corrosion of metallic pipelines due to a.c. interferences caused by inductive, conductive or capacitive coupling with a.c. power systems and with the maximum tolerable limits of these interference effects. It takes into account the fact that this is a long-term effect which occurs only during normal operating conditions. Short term a.c. interferences appearing during fault conditions in the a.c. power system will not cause a.c. corrosion. This standard does not deal with the safety issues associated with a.c. voltages. These are covered in national standards and regulations (see FprEN 50443).