Summary
The paper is aimed to analyse the influence of the degradation, in the course of time, of pipelines insulating coating in the frame of power frequency electromagnetic interference generated by power lines on buried metallic pipelines. To our knowledge, such an issue is generally not considered when evaluating induced voltage and current along the pipe‐earth circuit; on the contrary, such a phenomenon should be taken into account because under certain conditions, the level of the electromagnetic interference can significantly vary during the pipeline life (some tens of years). In the paper, we propose an empirical law to describe the degradation in the course of time of the pipe insulation resistance to soil, and we show, by means of simple examples of interference calculation, why such a degradation should be taken into account. Copyright © 2016 John Wiley & Sons, Ltd.