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 protection criteria given in EN 12954:2001, Table 1, are not sufficient to demonstrate that the steel is being protected against corrosion. This European Standard provides limits, measurement procedures, mitigation measures and information to deal with long term a.c. interference for a.c voltages at frequencies between 16,7 Hz and 60 Hz and the evaluation of a.c. corrosion likelihood. This European Standard deals with the possibility of a.c. corrosion of metallic pipelines due to a.c. interferences caused by inductive, conductive or capacitive coupling with a.c. power systems and the maximum tolerable limits of these interference effects. It takes into account the fact that this is a long-term effect, which occurs during normal operating conditions of the a.c. power system. This European Standard does not cover the safety issues associated with a.c. voltages on pipelines. These are covered in national standards and regulations (see EN 50443).