scope:

Part 3 of the standard applies to direct acting indicating wattmeters and varmeters having an analogue display.

Note. - For multifunction instruments, see Part 7.

This part also applies to non-interchangeable accessories (as defined in Sub-clause 2.1.15.3 of Part 1) used with wattmeters and varmeters.

This standard also applies to a 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.

This standard also applies to 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.

This standard does not apply to special purpose devices which are covered by their own IEC standards when they are used as accessories.

This standard does not contain either requirements for protection against environmental conditions or the relevant tests. However, when necessary, and then only by agreement between the manufacturer and the user, tests to approximate the conditions of use may be selected from IEC Publication 68 : Basic Environmental Testing Procedures, to prove protection against environmental conditions.

This standard does not specify requirements concerning dimensions of instruments or accessories (for the former, see IEC Publication 473 : Dimensions for Panel-mounted Indicating and Recording Electrical Measuring Instruments).