Section R. 460.3607 - Watt-hour meter requirementsRule 607.
(1) Watthour meters that are used for measuring electrical quantities supplied must conform to ANSI C12.1 or C12.20 specifications and meet all of the following requirements:(a) Be of proper design for the circuit on which the meters are used; be in good mechanical and electrical condition; and have adequate insulation, correct internal connections, and correct register.(b) For electro-mechanical meters, not creep at no load with all load wires disconnected at a rate of 1 complete revolution of the moving element in 10 minutes when potential is impressed.(c) Be accurate to within plus or minus 1% for electro-mechanical meters and 0.8% for solid state meters, referred to the portable standard watthour meter as a base, at 2 unity power factor loads: light load (l.l.) and full load (f.l.). Meter Class | Light Load Amperes | Full Load Test Amperes | Inductive Load 50% Lagging Power Factor Test Amperes |
Self-Contained | 10% Rated Test Amperes of Meter | 100% Rated Test Amperes of Meter | 100% Rated Test Amperes of Meter |
Transformer-rated | 10% Rated Test Amperes of Meter | 100% Rated Test Amperes of Meter | 100% Rated Test Amperes of Meter |
(d) Be accurate to within plus or minus 2% for electro-mechanical meters and 1.6% for solid state meters, referred to the portable standard watthour meter as a base, at inductive load (i.l.).(2) Polyphase meters must have their elements in balance within 2% for electromechanical meters and 1.6% for solid state meters at rated test amperes at unity power factor and at approximately 50% lagging power factor.Mich. Admin. Code R. 460.3607
1983 AACS; 2008 AACS; 2023 MR 7, Eff. 4/10/2023