This second edition updates references to relevant regulations, standards and publications. It replaces references to the Institution of Electrical Engineers' IEE Regulations with BS7671. This book is relevant to all work activities and premises except mines and quarries, certain offshore installations and certain ships. The guidance is intended to assist duty holders in meeting the requirements of the Regulations. It will be of interest and practical help primarily to engineers (including those involved in the design, construction, operation or maintenance of electrical systems and equipment), technicians and their managers.