This standard contains the requirements for the design and erection of electrical installations in systems with nominal voltage above 1 kV a.c. so as to provide safety and proper functioning for the use intended. The electrical power installation (substations; generating stations located on a single site; electrical system of a factory, industrial plant etc) includes among others, the following equipment: generators, motors and other rotating machines; switchgear; transformers; converters; cables; lines; wiring systems; batteries; capacitors; earthing systems; buildings and fences which are part of a closed electrical operating area; associated control equipment. This standard does not apply to the design and erection of: overhead and underground lines between separate installations; electric railways (but does apply to the substation feeding a railway system); mining equipment and installations (except for opencast mining); fluorescent lamp installations; electrostatic equipment; test sites; medical equipment e.g. medical X-ray equipment. This standard does not apply to the design of factory-built, type tested switchgear for which separate IEC or CENELEC standards exist.