ANSI C12.20 is an ANSI standard that describes an American National Standard for Electricity Meters - accuracy and performance.
The C12.20 standard established the physical aspects and performance criteria for a meter's accuracy class. It supersedes certain details in ANSI C12.1 and ANSI C12.10.
The existing ANSI accuracy classes for electric meters are:
Outside North America, IEC standards are used for electric meters.