Rhode Island Code of Regulations
Title 815 - Division of Public Utilities and Carriers
Chapter 30 - Electric Utilities
Subchapter 00 - General Administration
Part 1 - Standards for Electric Utilities
Section 815-RICR-30-00-1.7 - Meter Accuracy and Testing

Universal Citation: 815 RI Code of Rules 30 00 1.7

Current through September 18, 2024

1.7.1 Inspection of Meters

A. Meters removed from service. All meters removed from service, which are to be reinstalled, shall be inspected and tested for correctness. In addition, worn or damaged parts shall be replaced.

B. Meter installations. All polyphase meters and demand devices shall be tested before installation to ensure accuracy of operation when installed. In connection with installation an electrical check shall be made of all instrument transformer connections.

C. Test and Calibration of Meters.
1. Polyphase Meters. All polyphase meters shall be tested at loads and adjusted to tolerances as follows:

Test Load in Rated Meter Capacity

Power Factor

to Tolerance of

100%

1.0

Plus/Minus 1%

10%

1.0

Plus/Minus 1%

100%

0.5

Plus/Minus 2%
a. Meters also shall be checked for "creep" at no load and rated voltage.

2. Demand Devices. All indicating and recording demand devices shall be adjusted as follow:
a. Zero Adjustment - No demand device that fails to reset properly to zero shall be placed in service or allowed to remain in service without adjustment.

b. Up-Scale Check - Tests to determine the accuracy of a demand device shall be made at a point approximately mid-scale. No demand under test having an error in indication or registration of more than 2% plus or minus (in terms of full scale deflection) shall be placed, or allowed to remain, in service without readjustment.

c. Time Cycle Devices - All motors used to maintain a timing cycle where such timing cycle directly affects meter registration, shall be tested to insure operation at the proper speed.

1.7.2 Test Schedules for all Watthour Meters and Demand Devices

A. New Meters. The manufacturer's test on all new meters will be accepted as a first test on a meter and so recorded if built to the EEI-AEIC-NEMA or ANSI standard for Polyphase meters.

B. All alternating current watthour meters and demand devices in service shall be tested in accordance with the following requirements.
1. Meters up to and including 12KVA shall be tested in accordance with either §§1.7.2(B)(1)(a) or (b) of this Part. The Schedule initially adopted by the public utility shall not be changed without notifying the Division.
a. Periodic Test Schedule. Watthour meters may be tested on periodic basis by which every meter shall be tested at least once every twelve (12) years.

b. Selective Test Plan. Watthour meters may be tested under a selective plan as follows.
(1) Selective Test Population. This shall include those single-phase common or residential type meters of 0-12 KVA capacity. It shall not include those specific meter groups known to be adversely affecting overall meter accuracy, if these meters are placed on a fixed retirement program not exceeding five (5) years. Meters removed due to a fixed retirement program need not be tested by the utility.

(2) Sample Test Group. A Sample Test Group representing a cross-section of the meters in the Selective Test Population on company lines shall be selected at random and tested each year. The Sample Test Group shall be at least 1% of meters in the Selective Test Population, but not less than 500 meters. For a company having less than five thousand meters, the Sample Test Group shall be at least 2% of meters in the Selective Test Population, but not less than 40 meters.

(3) Cumulative Sample Test Group. The Cumulative Sample Test Group includes the Sample Test Group of the current year plus those of the immediately preceding years to a maximum of five Sample Test Groups.

(4) Number of Meters to be Tested. The percentage of meters in the Cumulative Sample Test Group which displays a weighted average accuracy outside the limits of 98% to 102% shall be used to determine from the test Ratio Curve the minimum number of meters to be tested (Total Meter Test Group) in the ensuing year.

(5) Supplemental Test Group. The Supplemental Test Group is the difference between the Total Meter Test Group and the Sample Test Group.
(AA) Supplemental = (Total) - (Sample)

(BB) Tests of meters which are part of the Selective Test Population and which are returned to the shop for maintenance may be credited toward completion of the Supplemental Test quota. Additional meters selected to fill the Supplemental Test quota shall be either:

(CC) Meters in service without a test, or meters of specific types which are contributing a greater than average percentage of the meters outside the limits of 98% to 102%.

(DD) Specific meter groups known to be adversely affecting over-all meter accuracy, if placed on a fixed retirement program not exceeding five years may be excluded from the Selective Test Population. Meters removed due to a fixed retirement program need not be tested by the utility.

(EE) Such meters on a retirement program shall be junked at a uniform annual rate to eliminate them from Company lines in five years or less from the start of the program. If the retirement rate is not maintained, all remaining meters in the group must become part of the Selective Test Population and subject to the Selective Test Procedure.

C. Meters in excess of 12KVA and not exceeding 100 KVA shall be tested on a periodic basis by which every meter shall be tested at least once every six (6) years.

D. Meters in excess of 100 KVA shall be tested on a periodic basis by which every meter shall be tested at least once every (5) years.

E. In lieu of the periodic and selective test plans described in §§1.7.2(B), (C) and (D) of this Part, a utility may, after notifying the Division, implement a statistical sample testing program based on the provisions of the most current version of ANSI/ASQC Z1.9, American National Standard Sampling Procedures and Tables for Inspection by Variables for Percent Nonconforming or on the provisions of a comparable nationally recognized statistical sampling methodology.

F. Integrated demand meters shall be subject to the same periodic tests or sample tests as the meters with which they are associated.

G. For the purpose of §1.7.2(C) of this Part, the KVA rating of a Self-contained AC Watthour Meter is the product of the rated voltage in Kilo-volts, the rated test amperes and the number of stators. The KVA rating of an instrument transformer classed watthour meter is the product of the primary voltage in Kilo-volts, the nameplate rating of the current transformers, and the number of stators.

H. All meters over 12 KVA capacity removed from service and not yet due for testing must be tested and recalibrated before being put back into service. These tests may be included as a part of the periodic or statistical sampling test populations.

1.7.3 Request Tests

A. All request tests must be made with the meter in its service location whenever practicable to do so.

B. Tests by public utility. When requested by a customer, each public utility shall test the accuracy of the customer's meter within fifteen (15) days from the time the request is made. If the meter has been tested during the preceding thirty-six (36) months, a public utility may require the deposit of a fee of twenty-five dollars ($25) for such a test. If on testing the meter is found to be fast by more than 2%, the deposit shall be promptly refunded. If the meter is not found to be fast by more than 2% the public utility shall retain the amount deposited for the test. A customer may be represented in person or by an agent when the public utility conducts the test on the customer's meter. A report giving the name of the customer requesting the test, the date of the request, the location, the type, make size, the serial number of the meter, the date tested, and the result of the test shall be supplied to such customer within a reasonable time after the completion of the test.

C. Tests by Division. Upon written application to the Division by a customer, a test will be made of the customer's meter in the presence of the Division's representative as soon as practicable. Each application to the Division for test of a meter shall be accompanied by a fee of twenty-five dollars ($25). If upon testing, the meter is found to be fast by more than 2%, the Division shall return to the customer the amount of fee paid by the customer to the Division. When notified of an application submitted to the Division by a customer for a referee test as herein provided, the public utility shall not knowingly remove, interfere with, or adjust the meter to be tested without the written consent of the customer and approved by the Division.

1.7.4 Reporting Requirements

A. For utilities that test according to the periodic test schedules or selective tests plans described in §§1.7.2(B), (C) and (D), reports of periodic and sample tests of meters shall be reported to the Division on Form E-2 and Form E-2A once a year, or on the public utility's Standard Meter Test Report Form.

B. For utilities that implement the statistical sample testing program as described in subparagraph §1.7.2(E), reports of in-service and request tests of watthour meters shall be made each year and filed with the Division not later than the 15th day of March the following year. All reports of in-services tests are to include the number of meters tested, the number of meters found outside of limits, and the size of the population. Where appropriate, the reports should break down the population of meters by type and be accompanied by appropriate performance parameters for that type.

C. A complete record of the latest test made on a meter shall be retained in the public utility's files for three (3) years.

1.7.5 Billing Adjustments

A. Calculation of Error. The accuracy of registration of the meter and its performance in service shall be determined by its average error, as follows:
1. The average error shall be the weighted average of its error at light load with a weighting of one and its error at heavy load with a weighting of four.

2. Any adjustment of charges that is made in accordance with this rule shall be based on such average error.

B. Adjustments.
1. Fast Polyphase Meters. Whenever a polyphase meter is found to be fast in excess of 2% of the correct amount, the Company shall refund to the customer an amount equal to the charge for the excess kilowatt hours billed for the twelve (12) month period immediately preceding such test, unless the time when the error first developed, or occurred can be definitely fixed, in which case the amount to be refunded shall be calculated from that time. Under no circumstances will an adjustment of a customer's bill be made if there is evidence that the meter has been tampered with.

2. Slow Polyphase Meters. Whenever a polyphase meter is found to be slow in excess of 2%, the Company may make a charge to the customer for the unbilled kilowatt hours supplied for the previous twelve (12) months or since the last test, whichever is the shorter period. However, where there is evidence that the meter has been tampered with, the Company may charge the customer for all unbilled kilowatt-hours supplied since the estimated data of the tampering.

3. Non-Registration. If a meter is found which does not register, the bill for the period of non-registration shall be based upon information recorded prior or subsequent to the period of non-registration and by any other pertinent information supplied by the customer or known to the public utility.

1.7.6 Testing Facilities and Equipment:

A. Single Polyphase Standards.
1. Laboratory Standards. Every public utility shall have available one or more laboratory standards for the sole purpose of checking working standards. All standards shall be certified at least once each year in a laboratory acceptable to the Division. Each standard shall be accompanied by calibration tables noting the corrections at various working loads. These calibration tables when superseded shall be kept on file in the office of the public utility for a period of two (2) years.

2. Each public utility shall have an adequate number of working standards for testing customers' meters. These working standards shall be compared to laboratory standards at least once every twelve (12) months. Each working standard shall be accompanied by a calibration table noting the corrections at various working loads. These calibration tables, when superseded shall be retained by the public utility for a period of two (2) years. If comparisons with the laboratory standards show the working standard to be in error by 1% or over, it shall be recalibrated and/or replaced. In case a public utility does not maintain a reference watthour standard, the working standards must be checked every twelve (12) months in a laboratory acceptable to the Division.

B. Each public utility shall have an adequate number of working standards for testing customers' meters. These working standards shall be compared to laboratory standards at least once every twelve (12) months. Each working standard shall be accompanied by a calibration table noting the corrections at various working loads. These calibration tables, when superseded shall be retained by the public utility for a period of two (2) years. If comparisons with the laboratory standards show the working standard to be in error by 1% or over, it shall be recalibrated and/or replaced. In case a public utility does not maintain a reference watthour standard, the working standards must be checked every twelve (12) months in a laboratory acceptable to the Division.

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