DIN EN 60051-3:2017-02

Part 3 of the standard applies to direct acting indicating wattmeters and varmeters having an analogue display. It also applies to: Non-interchangeable accessories (as defined in Subclause 3.1.23 of IEC 60051-1:2016) used with wattmeters and varmeters. Combination of the instruments and the accessories provided that the adjustments have been made for the combination; Direct acting indicating electrical measuring instrument whose scale marks do not correspond directly to its electrical input quantity, provided that the relationship between them is known; Instruments and accessories having electronic devices in their measuring and/or auxiliary circuits. This standard does not apply to: Special purpose instruments which are covered by their own IEC standards; Special purpose devices which are covered by their own IEC standards when they are used as accessories.