This paper discusses some practical configurations for finding flaws in well‐conducting materials using the eddy‐current non‐destructive method (NDT). In order to increase the sensitivity of impedance changes the optimisation of all properties of these systems e.g. design and dimensions of the coils, their positions, frequency and measuring system has been carried out. Based on these results some requests are formulated for the developer of NDT‐sensors. This project has been carried out as the World Federation Second Eddy Current Benchmark Problem. © 2003 American Institute of Physics