Section 460.400  Accuracy Testing of Meters

a)         Each service watt-hour meter and var-hour meter shall be inspected and tested according to the schedule in subsection (b). At the time a service watt-hour meter or var-hour meter is tested, any demand meter associated with it shall be inspected or tested. Each demand meter shall be tested at least as often as the meter with which it is associated and, as nearly as practicable, at the same time. If the service watt-hour meter is of the type in which the same element that measures watt-hours is used to measure demand, then the watt-hour test and the demand test shall be considered to be one and the same.

b)         Alternating current service watt-hour meters and associated var-hour meters shall be tested according to the following schedule:

1)         Self-contained single-phase and three-wire network meters:

A)        Non-demand:

i)          Sample according to Section 460.410;

ii)         8 years;

B)        Demand:

i)          with pulse-operated electronic demand registers: 4 years;

ii)         with surge-proof magnets or solid state: 8 years.

2)         Self-contained 480 volt single-phase and poly-phase meters; transformer-rated single-phase meters:

A)        Non-demand:

i)          with surge-proof magnets: 8 years;

ii)         without surge-proof magnets: 4 years;

B)        Demand:

i)          Mechanical meters with pulse-operated electronic demand registers: 4 years;

ii)         with surge-proof magnets or solid state: 8 years.

3)         Transformer-rated poly-phase meters: 8 years.

c)         Direct current watt-hour meters shall be tested at least once every 12 months.