Specifies the quality, performance and test procedures for electro-mechanical relays for control and switching circuits whose rated coil voltages do not exceed 500 V a.c. or 440 V d.c. and whose contact ratings do not exceed 20 A a.c. or d.c., 500 V a.c. or 440 V d.c. Also gives general rules for preparing detail specifications, marking requirements and relevant terminology.