This book deals with an area of practice that many students and non-electricians find particularly challenging. It explains how to interpret circuit diagrams and wiring systems, and outlines the principles of testing before explaining how to apply this knowledge to fault finding in electrical circuits. A handy pocket guide for anybody who needs to be able to trace faults in circuits, whether in domestic, commercial or industrial settings, this book will be extremely useful to electricians, plumbers, heating engineers and intruder alarm installers. Fully up to date with the 18th Edition IET Wiring Regulations 2018. Covers all the principles and practice of testing and fault diagnosis in a way that is clear for students and non-electricians. Expert advice from an engineering training consultant, supported with colour diagrams and key data.