This part of EN 50397 provides general recommendations for the selection, storage, transportation and installation of the covered conductors and the related accessories specified in Parts 1 and 2 of the standard, unless otherwise specified. Safety regulations and environmental regulations as well as rules for installation and mechanical design are not considered in this Guide to use, as they are covered by relevant national regulations and laws. Relevant national regulations are not considered in this guide, but shall always be consulted as appropriate. NOTE The term "national regulations" is used throughout this guide. It may include specific safety regulations, rules of installation and other relevant instructions which, depending upon the particular country or district, may exist in a legislative (mandatory) form, or as a non-mandatory code of practice. In addition certain specific utilities may have their own safety practices. It is assumed that the design of installations, the purchase and installation of covered conductors and of the related accessories specified in this EN is entrusted to suitably skilled and competent people. In case of doubt as to the suitability of covered conductors and the related accessories for a particular use, further specific information shall be obtained from the manufacturer.