NEMA C12.4
NEMA C124 1984-JAN-01 Regsters - Mechancal Demand
The standard covers the voltage and frequency rating, full-scale values, scale classes, demand intervals, multiplying constants, timing mechanism, and other general features of mechanical demand registers required for use on watthour meters. Since mechanical demand registers are designed for use as accessories in watthour meters, items relating to watthour meters are not covered in this standard; these items are dealt with in several other standards.