Electricity meters are designed to record the amount of electricity consumed with acceptable accuracy. Any major mistakes can affect consumers and utility companies, as it could mean consumers being overbilled, or losses to suppliers. The required accuracy is dictated by the laws of the place where the meter is installed, which may also outline the procedures that must be followed in the event of a dispute over the accuracy of the meter. For example, in the United States, the American National Standards Institute (ANSI) develops voluntary standards that form the basis for the testing requirements set by most utilities and utility commissions for their meter requirements.
The meter is single phase MID electric energy meter divided into three accuracy classes, 0.1, 0.2 and 0.5, which means that the error rate of the meter under test conditions does not exceed 0.05%, 0.1% and 0.2%, respectively. For net metering, the test conditions must be applied twice – once with the energy flowing in the forward, or “transmitting” direction, and once with the energy flowing in the reverse, or “receiving” direction. If the accuracy of a meter is in dispute, the meter can be compared to a check meter that was run with the disputed meter, or a more thorough test at a designated calibration laboratory to verify accuracy.
