ANSI C12.5:1978 (R2012)

This standard covers the class designations, voltage and frequency ratings, scale values, demand intervals, multiplying constants, mounting dimensions, terminal arrangements, and other features of general-service-type thermal watt demand meters and watthour-thermal watt demand meters. Although this standard specifically refers to watt demand meters, it is suggested that ampere and volt-ampere demand meters follow the applicable requirements so far as practicable.