In April 2016, Energy Solutions has successfully performed the “Pluskwalificatie” test for performing magnetic field calculations according to the instructions from the RIVM. The RIVM (Rijksinstituut voor Volksgezondheid en Milieu) is the National Institute for Public Health and the Environment. Magnetic field calculations according to the “Pluskwalificatie” are used in situations where multiple overhead high voltage lines are present in a small area. Since 2010, Energy Solutions was already qualified for performing magnetic field calculations according to the guidelines from the RIVM for standard situations. Energy Solutions decided to apply for the plus qualification because of a request to perform magnetic field calculations in an newly constructed residential area which is build close to a 380 kV overhead line. Close to this area, also two other 150 kV overhead lines are present which needed to be included in the calculations. The software for performing the magnetic field calculations with multiple overhead lines, has been developed by Energy Solutions itself. Because the results of the “Pluskwalificatie” test were within the prescribed requirements, it has been proved that the software is suitable to perform advanced calculations for situations were multiple overhead lines influence each other’s magnetic field.