This standard specifies the classification, requirements, test methods, inspection rules, signs, packaging and storage of fixed-installed multi-rate electric energy meters (hereinafter referred to as meters). The special requirements of the electric energy measuring unit of the instrument shall comply with the provisions of the relevant electric energy meter standards respectively. This standard applies to multi-rate energy meters that measure AC active and/or reactive energy with a reference frequency of 50Hz (or 60Hz). This standard is only applicable to multi-rate electric energy meters whose time switches are digital displays and which use batteries (or capacitors) to provide working reserves. This standard does not apply to multi-rate energy meters whose time switches are analog dials.