Specifies service conditions and performance requirements for surge arresters (diverters) of the non-linear silicon carbide resistor type with single or multiple series spark gaps and which are designed for repeated operation to limit voltage surges in 50 Hz a.c. circuits. Sections include definitions, rating and marking, arrester classification and test requirements, tests and test procedures. Appendices cover special service conditions, information to be provided by the purchaser, application guide, impulse voltage and current wave shapes, measurement of leakage, typical test circuits, artificial pollution testing and items subject to agreement between purchaser and manufacturer.