Describes the product safety requirements for measuring relays and protection equipment having a rated a.c. voltage up to 1 000 V with a rated frequency up to 65 Hz, or a rated d.c. voltage up to 1 500 V. Details essential safety requirements to minimize the risk of fire and hazards caused by electric shock or injury to the user.The contents of the corrigendum of March 2007 have been included in this copy.