A pipeline current mapper or pcm is a tool utilized for perform an ac current attenuation survey to qualitatively rank coating quality and highlight pipeline locations with the most significant coating holidays defects . An ac current is implemented in the pipeline and coating damage is located and prioritized derived from the magnitude of current attenuation. Ac current attenuation surveys can be carried out with impressed current cathodic protection systems energized. When sacrificial anodes frequently called galvanic anodes are linked with the pipeline either directly or through a it is, Test station recommended that they be disconnected when feasible when performing pipeline coating quality testing to prevent signal loss and enhance current flow down the pipeline.