During the last years the EC has issued for important product groups totally 20 guidelines according to the ”New Approach” which must be moved into national right by the member states of the European Union. The EC refers in these guidelines to the establishing of the basic technical requirements concerning security and health protection. To put the general legal requests into actual form, the EC engages the European Standardization Institutes (CEN, CENELEC, ETSI) with the creation of European Standards (EN). With the publication in the EC official gazette, these attain the status of harmonized standards. With the CE designation as well as the conformity explanation, PMA certifies the accordance of the relevant products with the requirements of the low voltage guideline (73/23/EEC).