Guidance Note 7: Special Locations provides a comprehensive guide to the various special locations and installations for which additional measures are required to comply with BS 7671. It is designed for anyone working in special locations where guidance may vary, including consulting engineers, electricians, electrical installers, inspectors and technicians and has been fully updated to BS 7671:2018+A4:2026, including guidance on open-PEN detection devices; significant updated guidance for Medical Locations; bidirectional and unidirectional devices; Stationary Secondary Batteries, rating of distribution board with multiple sources; selection of RCDs; Power over Ethernet.