The monograph outlines the general principles for organizing the electrical safety system in electrical installations of residential and public buildings, provides information from a number of the latest regulatory documents governing the design of electrical installations and technical requirements for electrical protective devices. Types of electric shock, electrical safety criteria, basic electrical protective devices, principles of their operation, application rules, methods of control and testing of these devices are considered, examples of their use in various electrical installations are given. In addition, information on systems for monitoring insulation and lightning protection of electrical installations is presented. Methods of first aid in case of electric shock are also considered.