The article is dedicated to the optimization and operation of magnetic slip-shields with the purpose of redistributing the field in the space near the cable line (the electromagnetic field source). The optimization was made by means of a genetic algorithm (GA). As a result, the authors found optimal designs of shields for various cable line layouts. Moreover, the study shows manufactured prototypes of the shields and the testing results. This investigation demonstrates the possibility of applying slip-shields to mitigate the amplitude of the electromagnetic field in the specified areas around the cable.