North Carolina Administrative Code › Title 04 - COMMERCE › Chapter 11 - UTILITIES COMMISSION › Chapter 8 › Article 3 - METERS, METER TESTS AND RECORDS › Section 11 R08-13 - IN-SERVICE METER TESTING

Current through Register Vol. 39, No. 2, July 15, 2024
(a) Meter
				  Testing Required - Each in-service watt hour billing meter shall be included in
				  either a periodic or sampling testing plan as prescribed by ANSI C12.1 - Code
				  for Electricity Metering. Average meter registration accuracy that is less than
				  98% or more than 102% will be counted as a failure.
(b) Statistical Sampling Plan - The
				  statistical sampling plan provides for the division of meters into homogenous
				  groups such as manufacturer and manufacturer type and may be further subdivided
				  based on other factors such as age or vintage of meter. The selection process
				  is random where each meter within each group has an equal chance of being
				  selected. Selected meters in each group are tested for energy registration
				  accuracy. The statistical sampling plan used shall conform to the accepted
				  principles of statistical sampling as found in ANSI Z1.4 - Sampling Procedures
				  and Tables for Inspection by Attributes, ANSI Z1.9 - Sampling Procedures and
				  Tables for Inspection by Variables for Percent Nonconforming, or other
				  statistically valid programs that have been evaluated by qualified independent
				  mathematical statisticians.
(c)
				  Periodic Interval Plan - Every meter included in a periodic interval plan shall
				  be tested for energy registration accuracy at a minimum of once every sixteen
				  years. The utility may elect to test more frequently based on factors such as
				  complexity of the metering system, class of customer, or size of
				  service.
(d) Corrective Action - If
				  testing pursuant to subsection (a) or (b) shows that a meter or group of meters
				  does not meet the performance criteria, then an established program of
				  corrective action shall be followed. Corrective action shall consist of one or
				  more of the following methods listed in ANSI C12.1 section 5.0.3.4.4: a) an
				  accelerated test program, b) splitting a group into two or more subgroups, c) a
				  time-specific retirement program, or d) a sample-driven retirement program. The
				  accelerated test program should provide for testing at rates that vary in
				  accordance with the calculated percentage of meters in the group outside the
				  acceptable limits of accuracy but not less than 20% of the group tested per
				  year. Meters so tested and placed into service shall be sampled as a separate
				  group from the remainder of the original group not tested. When the sample
				  results of the remainder of the original group indicate that the group has come
				  up to acceptable limits the two components of the group may be consolidated for
				  sampling.
(e) Utility to Retain
				  Test Results - Accuracy test results shall be stored by the utility for the
				  life of the meter and at least three years after the retirement of the
				  meter.
(f) Utility Reporting - No
				  later than April 1 of each year, a utility shall report to the Commission on
				  its in-service meter program. For tests performed pursuant to subsection (b),
				  the report shall indicate the number of meters in each homogeneous group in
				  service at the beginning of each year, the number of meters making up the
				  sample for each such group, the test results for each group, and any corrective
				  action taken. In addition, the report shall describe the results from meters
				  tested under a periodic interval plan pursuant to subsection (c), including the
				  number of meters in each homogeneous group in service at the beginning of each
				  year, the number of meters tested, the test results, and any corrective action
				  taken. The report shall also identify any classes of meters for which the
				  utility tests on a more frequent basis than prescribed in ANSI C12.1, and the
				  basis for the more frequent testing. The report shall also outline the current
				  year's testing plan.
(g)
				  Inspections - When metering installations are tested or inspected, instrument
				  transformers and wiring associated with the installation shall be visually
				  inspected for correctness of connections and evidence of damage. Nameplate or
				  stenciled ratios shall be verified against ratios used by the utility for
				  billing. These inspections are not required if performing them cannot be done
				  safely.
NCUC Docket No. M-100,
					 Sub 5, 7/15/65; NCUC Docket No. E-100, Sub 4, 6/8/66; NCUC Docket No. M-100,
					 Sub 140, 12/03/13; NCUC Docket No. E-100, Sub 153,
					 11/27/2019.