Mich. Admin. Code R. 460.3607 - Watt-hour meter requirements

Rule 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.

Notes

Mich. Admin. Code R. 460.3607

1983 AACS; 2008 AACS; 2023 MR 7, Eff. 4/10/2023