Updated in line with the 18th edition of the wiring regulations. This book is an essential guide to the City & Guilds 2391-50 and 51: Initial Verification and Certification of Electrical Installation and Periodic Inspection and Testing, also C&G 2391-52: an amalgamation of Initial Verification and Periodic Inspection and Testing of electrical installations. There is a full coverage of technical and legal terminology used in the theory exams; including the structure of exam questions and their interpretation. By running through examples of realistic exam questions in a step-by-step fashion, this book explains how to decode the questions to achieve the most suitable response from the multiple-choice answers given.