The paper discusses the considerations affecting the management of protective gear on power supply systems.In Section (2) the extent of the responsibilities and the qualifications of protective-gear engineers is reviewed.A number of simplifying assumptions which can be made when calculating power-system fault currents and voltages are given in Section (3). This Section also discusses system abnormalities other than faults, and their relationship to protective-gear operation.Section (4) mentions certain characteristics of protective gear which affect its performance and correct application.A general outline of the work which should be carried out on protective gear before commissioning is given in Section (5). Detailed consideration is then given to the way in which this work should be carried out on various types of gear. A description of general methods of testing and of testing-equipment follows in Section (6).Section (7) is devoted to consideration of protective-gear troubles and routine maintenance procedure.Finally, in Section (8) certain features of protective-gear design, construction and layout which assist maintenance are discussed.