Specifies requirements for non-linear metal-oxide resistor type surge arresters, designed to limit voltage surges on a.c. power circuits. Sections cover service conditions, definitions, ratings, marking, classification, test requirements, type tests and procedures. Appendices cover special service conditions, information to be provided by the purchaser, application guide, impulse voltage and current waveforms, typical circuit for operating duty test, supplementary definitions and test requirements for metal-oxide arresters with series spark-gaps, artificial pollution test and items subject to agreement between the purchaser and the manufacturer.