This book presents the principles and design of low-voltage systems at both the device and system levels. It provides the characteristics, specifications and industrial standards of various types of circuitbreakers, fuses and cables. Utility supply systems, utility earthing systems and consumer earthing systems are introduced. Standard design procedures, overcurrent and earth fault protection, the latest code of practice, and IEE Wiring Regulations are discussed and illustrated through a series of comprehensive and interesting application examples.