Capacitive sensor probes are used to detect defects in polyethylene pipe gas pipeline. These probes are attached to the pig before it is sent through the polyethylene pipe to detect any defects in the outside of the pipe wall. This is done by using a triple plate capacitive sensor in which electrostatic waves are propagated outward through the pipe's wall. Any change in dielectric material results in a change in capacitance. Testing was conducted by NETL DOE research lab at the Battelle West Jefferson's Pipeline Simulation Facility