83 Ill. Adm. Code 460.440
Corrections and Adjustments for Meter Error
Section 460
Section 460.440 Corrections
and Adjustments for Meter Error
a) Regardless of the source of inaccuracy in a customer's meter
usage data, the MSP shall correct the data and provide corrected data for all
affected billing periods to all entities billing the customer.
b) Whenever any test made by an MSP or by the Commission shows a
meter to have an average error of more than 2%, a correction of the metering
data shall be determined by the MSP and that correction shall be conveyed
within 3 business days to the customer and to other entities involved in
billing the customer.
c) When a meter is found to have an average error of more than
2%, the MSP shall determine the metering data correction using the actual
percentage of error as determined by the test, not the difference between the
allowable error and the error found as a result of a test.
d) If the meter is found to run faster than allowable, the MSP
shall determine the correction to the metering data for that meter. In
determining the correction it shall be presumed, unless demonstrated otherwise,
that the inaccuracy has existed for a period of two years. This period of
presumed inaccuracy shall not exceed the time for which records of the current
customer's usage exist.
e) If the meter is found to be slower than allowable, the MSP
shall determine the correction to the metering data for that meter. In
determining the correction, it shall be presumed, unless demonstrated
otherwise, that the inaccuracy has existed for a period of 1 year prior to the
test for small commercial and residential customers and 2 years prior to the
test for all other customers.
f) In the case of a non-registering meter that has been read
during the period of non-registration, the MSP shall not determine a correction
to metering data for estimated consumption extending over more than twice the
regular interval between readings.
g) No corrections to metering data for meter error shall extend
beyond the in-service date of the meter discovered to be in error, nor shall
any correction be required to extend beyond the date upon which the current
customer first occupied the premises at which the error is discovered.
h) Whenever an MSP or the Commission's representative finds that
a service watt-hour meter, while in service, exhibits creep, the MSP shall make
an estimate of the registration caused by the creep during the period as
specified under subsection (c) and shall make a corresponding correction in the
metering data.
i) Any correction to metering data made by the MSP and all
records relating to the adjustment of the customer's billing or charges shall
be retained for at least two years.
j) Provisions of this Subpart do not apply to situations in
which the customer's wires, meters or other service equipment have been
tampered with and the customer enjoyed the benefit of the tampering.