Book excerpt: This popular guide provides an understanding of basic design criteria and calculations, along with current inspection and testing requirements and explains how to meet the requirements of the IEE Wiring Regulations. The book explains in clear language those parts of the regulations that most need simplifying. There are common misconceptions regarding bonding, voltages, disconnection times and sizes of earthing conductors. This book clarifies the requirements and outlines the correct procedures to follow. It is an affordable reference for all electrical contractors, technicians and other workers involved in designing and testing electrical installations. It will answer queries quickly and help ensure work complies with the latest version of the Wiring Regulations. With the coverage carefully matched to the syllabus of the City & Guilds Certificate in Design, Erection and Verification of Electrical Installations (2391-20) and containing sample exam questions and answers, it is also an ideal revision guide. Brian Scaddan, I Eng, MIET, is a consultant for and an Honorary Member of City & Guilds. He has over 35 years’ experience in Further Education and training. He is Director of Brian Scaddan Associates Ltd, an approved City and Guilds and NICEIC training centre offering courses on all aspects of Electrical Installation Contracting including the C&G 2391 series. He is also a leading author of books on electrical installation.