Residual Current Devices: Selection, Operation, and Testing looks at the evolution in construction types of residual current devices and discusses the types and functional properties of contemporary systems. The principle of operation of elements is explained, along with the primary parameters of the devices and their selection and application, as well as the rules of backup protection of residual current devices. The requirements of the standards concerning the importance of obligatory use of devices are included, along with explanation of the needed protection in case of fault, additional protection, and protection against fire. The issue of residual current device operation in circuits with nonsinusoidal currents is detailed, giving special attention to the unique results of residual current device testing and tripping under distorted earth fault currents. In modern electrical and electronic installations, new complex challenges arise for designers and maintenance staff. This book is an essential guide to address those challenges, and its problem-solving section is useful for students, tutors, and academics, as well as engineers involved in the process of design, maintenance, and verification of safety in low-voltage electrical installations.