S-E-02— Specifications for the Verification and Reverification of Electricity Meters

S-E-02—Specifications for the Verification and Reverification of Electricity Meters (PDF, 138 KB, 38 pages)

Category: ELECTRICITY
Specification: S-E-02 (rev. 4)
Issue Date: 2010-10-14
Effective Date: 2011-02-01
Supersedes: S-E-02 (rev. 3)

S-E-02 (rev. 2): Summary of Amendments to S-E-02 (rev.1)
Section Description
5 Removed subsection 5.3, Testing facilities and realigned the numbering. Testing Facilities requirements were identified for removal under the 20 % reduction initiative as they are adequately addressed in section 19 of the Act.
6 Removed subsection 6.2, Nameplate and realigned the numbering. These requirements were identified for removal under the 20% reduction initiative. These marking requirements are adequately addressed in the specifications for approval and the notices of approval.
S-E-02 (rev. 3): Summary of Amendments to S-E-02 (rev.2)
Section Description
3 Reference to E-26 was added to 3.10
5.6 The section was added to clarify the reduced reverification period for meter that are not assessed for MADT.
5.9 A reference to LMB-EG-07 was added to clarify the requirements.
Annex A.2.1 The applicability section was expanded to include polyphase and demand electronic meters.
Annex A.3.2 This section was amended to add the non-performance observations required for demand meters.
Annex A.5.1 This section was amended to state the conformity determination for meters inspected 100% that are not new and cannot be calibrated.
Annex A.6.2 This section was amended to include the applicable requirements for demand meters
Annex A.6.7 This section was amended to state the conformity, marginal conformity, or nonconformity determination for meters inspected by acceptance sampling that are not new and cannot be calibrated.
Annex A.7(e) This section was added to state the outgoing quality requirements for meters 100% inspected.
S-E-02 (rev. 4): Summary of Amendments
Section Description
8.4 To state the purpose of the revision.
Annex A.1 The scope was expanded to include electro-mechanical meters.
Annex A.2.1 (b) This section was added to expand the applicability of the electro-mechanical meters which include, single phase, network and polyphase, self contained and transformer type energy only meters (Wh, VAh, Varh, Qh).
Annex A.3.2 This section was amended to state “electronic meters”
Annex A.3.3 This section was amended to include the non-performance observations for functionality verification (i.e. pass/fail) of electro-mechanical meters.
Annex A.6 This section was amended to include acceptance sampling of electro-mechanical energy only meters.
Annex A.6.2(f)(i) This section was stated not to be applicable to electro-mechanical meters.

Table of Contents

1.0 General

1.1 Scope

These specifications apply to any electricity meter submitted for verification or reverification under the Electricity and Gas Inspection Act.

2.0 Authority

These specifications are issued under the authority of section 18 of the Electricity and Gas Inspection Regulations.

3.0 Normative References

3.1 Electricity and Gas Inspection Act

3.2 Electricity and Gas Inspection Regulations

3.3 Measurement Canada, LMB-EG-07: Specification for the Approval of Type of Electricity Meters, Instrument Transformers and Auxiliary Devices.

3.4 National Standard of Canada, CAN/CSA-Z234.4-89: All-Numeric Dates and Times. (Reaffirmed 2000-05-25).

3.5 International Organization for Standardization, ISO 3534-2:1993: Statistics - Vocabulary and Symbols - Part 2: Statistical Quality Control.

3.6 S-S-01, Specifications for the Generation of Pseudo-Random Samples

3.7 S-S-02, Measurement Uncertainty and Meter Conformity Evaluation Specifications

3.8 S-S-03, Prerequisites to the Use of Sampling Inspection

3.9 S-S-04, Sampling Plans for the Inspection of Isolated Lots and Short Series Lots

3.10 E-26, Reverification Periods for Electricity Meters and Metering Installations

4.0 Definitions

Act

The Electricity and Gas Inspection Act (EGIA).

Auto Service Detect Meter

Meters which are capable of determining service configurations.

Advanced Meter Function

A function built into a meter which uses metered information to provide additional information directly related to the establishment of a charge for electricity. Examples include, pulse constance, meter multipliers, loss compensation.

Case (of a Meter)

The complete enclosure.

Configurable Meter

A meter that is designed such that its service configuration can be modified either by software or hardware to make it compatible with different circuit arrangements. This may be performed automatically or by operator intervention. For example, a meter may be reconfigured from a 2½ element meter for metering a 3 phase, 4 wire wye circuit to a 2 element meter for metering a 3 phase, 3 wire circuit.

Constants:
Disk Constant Kh (Induction Type Meter)

The number of energy units being measured per disk revolution. For a watt hour meter the disk constant, Kh, is watt hours per revolution.

Pulse Initiator Output Constant Kp (Pulse Constant)

The number of energy units being measured per pulse output. The pulse may be from a KYZ output or any other pulse output device.

Single Phase Test Constant

A multiplication factor required to determine correct registration when testing certain multi-element meters using series-parallel, single phase testing techniques.

Test Constant Ks - (Electronic Meter)

The number of energy units being measured per indication of the meter’s test means (LED, LCD indicator, or other).

Cover (of a Meter)

That part of the case which is removable or can be opened, for access to the interior of the meter.

Current Range

The range of currents over which the meter or transformer is designed to function within specified error limits.

Current Transformer

An instrument transformer designed for the measurement and control of current.

Defect

A departure of a meter’s quality characteristic from its intended level or state, that occurs with a severity sufficient to cause the meter to not satisfy normal usage requirements. (Note: Depending on the nature and severity of the defect, it may cause a nonconformity to occur immediately or at some time in the future.)

Delivered Energy

Delivered Energy is the energy measured when current flows through the meter from the electricity grid to the load.

Demand

Demand is the average value of the power measured over a specified time interval. The following are the most commonly used types:

Integrating Demand (Block-Interval Demand)

Demand determined by measuring energy consumed over a fixed interval of time, divided by the time interval.

Lagged or Exponentially Responding Demand Meter

A demand meter in which the indication of the demand is determined by monitoring the exponential or thermal response to an applied load.

Demand Interval

The time duration over which the demand measurement is determined.

Maximum (or Peak) Demand

The greatest of all demands which have occurred during a specific period of time, usually the billing period.

Maximum (Full-Scale)Demand Rating

The largest demand that a meter is capable of metering within specified error limits.

Response Period - Exponential Demand Meter

The time required for the meter indication to reach 90 percent of the final response to a step change in the measured quantity.

Sliding Window (or Rolling) Demand

A method of demand measurement where the demand interval is the sum of contiguous fixed length sub-intervals.

Director

The Director as referenced in the Act and Regulations refers to the President of Measurement Canada, Department of Industry.

Display

A means for visual representation of metered quantities and other relevant information.

Electromechanical Meter

An electricity meter that incorporates mechanical elements to measure and register metered quantities.

Electronic Meter

A solid state electricity meter.

Element

The combination of the voltage sensing unit (i.e. sensor or coil) associated with a current sensing unit (i.e. sensor or coil).

Split coil element

The split coil element is comprised of a current sensing circuit which is associated with more than one voltage sensing circuit. Some times also referred to as the ‘Z-coil’ sensor.

Error
Absolute Error

The value registered by the meter minus the true value.

Relative (True) Error

The absolute error of measurement divided by the conventional true value of the measurand, and traditionally referred to as the “true error”. Expressed as a percentage, relative error is calculated as:

Er = ((Qm - Qs) ÷ Qs) × 100% = ((Qm ÷ Qs) -1) × 100%

where,

  • Er is the relative error of the meter under test, expressed in percent
  • Qm is the quantity indicated by the meter under test
  • Qs is the quantity indicated by the reference standard, expressed in the same units as Qm.
Full Scale (F.S.) Error

The ratio of the absolute error to the full scale value.

Percentage Error

The relative or full scale error multiplied by 100 percent (%).

Firmware

A program embedded in non-volatile memory of the meter.

Frame (of a Meter)

That part to which are affixed the working parts and adjustments.

Full Scale (F.S.) Value

The largest value of the actuating electrical quantity that can be indicated on the scale or, in the case of an instrument having its zero between the ends of the scale, the full-scale value is the arithmetic sum of the absolute values of the actuating electrical quantity corresponding to the two ends of the scale.

Energy Meter

A device which sums the elemental energy quantities of a measured input either continuously, or over a fixed interval of time for the case where the energy meter is used to determine demand.

Induction Type Meter

An energy meter which operates by the rotation of the disk of an induction measuring element.

Instrument Transformer

A transformer which is intended to reproduce in its secondary circuit, in a definite and known proportion, the current or voltage of its primary circuit with the phase relations substantially preserved.

Maximum Current Rating (Imax)

The largest current value for which a meter has been approved such that it maintains its performance within specified error limits. Nominally rated meters have an (Imax) equal to four times the nominal current rating for the meter.

Measuring Apparatus

A device or instrument that is used for the measurement of electricity for the purposes of calibrating electricity meters.

Meter

As defined in the Electricity & Gas Inspection Act (EGIA).

Meter Multiplier

The factor by which the meter reading must be multiplied to obtain the correct magnitude of the measured quantity.

Metrological Function, Feature, Characteristic, Parameter

Any function, feature, characteristic, parameter of a meter that provides a metered quantity or contributes to the determination of a quantity, which may be used for billing.

Minimum Current Rating (Imin)

The smallest current value for which a meter has been approved so that it maintains its performance within specified error limits.

Multifunction Meter

A meter capable of performing two or more measurement functions.

Multi-register Meter (e.g. Multi-rate Register Metering)

Means a metering application which records the measured values of electricity into different registers or “bins” (electronic or mechanical) based on various conditions such as time (i.e., time-of-use, real-time pricing), temperature, etc.

Nonconformity

A departure of a meter’s quality characteristic from its intended level or state, that occurs with a severity sufficient to cause the meter to not satisfy one or more specification requirements.

Normal Operating Mode

The operating mode assumed by the meter while in service without any operator intervention.

Phase Shifting Transformer - Phasing Transformer

An instrument transformer that is an assembly of two or more auto-transformers used as auxiliary instrument transformers, intended to be connected across the phases of a polyphase circuit so as to provide voltages in the proper phase relations for energizing var meters, var hour meters, or other measurement equipment.

President

The President of Measurement Canada having the authorities of “Director” as referred to in the Act.

Power Factor

The ratio of the active power to the apparent power. Under pure sine wave conditions, the power factor is given by cos φ where φ is the phase displacement between the voltage and the current.

Pulse Initiator

That part of a meter which produces pulses proportional in number to the value of the quantity being measured.

Pulse Recorder

A device which accumulates pulses from an external source representing integral units of energy.

Q Hour Meter

An electricity meter that measures energy by effectively lagging applied voltage by 60°.

Range, of an indicating or recording meter

The region covered by the span and expressed by stating the two end-scale values.

Note: If the span passes through zero, the range is stated by inserting "zero" or "0" between the end-scale values.

Rated Frequency

The frequency or frequencies at which the meter is designed to operate.

Rated Voltage

The voltage at which the meter or device is designed to operate, or for the case of meters designed for operation with a variety of voltage circuits, any preferred (as identified in Specifications for Approval of Type of Electricity Meters, Instrument Transformers and Auxiliary Devices) voltage at which the meter can operate may be considered as a rated voltage.

Received Energy

Received Energy is the energy measured when current flows through the meter from the load side of the service back to the electricity grid.

Reference Meter

A measuring instrument having errors traceable to the National Research Council of Canada, and used to establish the true value of a measurement.

Register
Electronic Register

An electronic medium used to store the value of a metered quantity.

Mechanical Register

A mechanical device that stores and presents the value of a metered quantity.

Register Ratio Rr - Induction Type Integrating Meter

The number of revolutions of the first gear of the register for one revolution of the first dial pointer.

Regulations

The Electricity and Gas Inspection Regulations (EGIR).

Reset Time - Mechanical Demand Register

The interval of time within each demand interval during which the driving element and demand indicator disengage from each other to allow the driving element to be restored to its initial position.

Reverification

Any subsequent confirmation of a meter’s conformance to legal requirements following its initial verification of conformance to those same requirements, performed upon expiration of the meter’s reverification period (i.e. seal period).

Seal

A means whereby unauthorized access to the interior, adjustments, or controls of a meter may be effectively detected.

Self-Contained Meter

A meter designed to be connected directly to a power circuit, without the use of external devices such as instrument transformers or shunts.

Series Test

A test performed on a meter whereby all voltage input circuits are energized with voltages of the same magnitude and phase relation, and all current input circuits are energized with currents of the same magnitude and phase relation. This may be accomplished by placing all meter voltage input circuits in a parallel circuit, and all meter current circuits in a series circuit.

Service Type

The number of wires and phases and the interconnection between them used to supply a metering load.

Single Phase Services

Single phase services may be provided as follows:

Two-Wire Service

A single phase two-wire service may be provided from many distribution systems, and normally has one conductor grounded, with a nominal voltage of 120V between conductors.

Three-Wire Service

A single phase three wire service may be provided from a single phase or polyphase distribution system. One conductor, the neutral, is grounded, and the normal service voltages are 240 V between the ungrounded conductors and 120 V between either of the ungrounded conductors and the grounded conductor.

Network Service

A network service is a three wire service supplied from a three phase, four wire, wye distribution system, with one of the conductors being the neutral conductor, and the other two conductors being phase conductors.

Polyphase Services

Polyphase services may be provided as follows:

Three Phase Three Wire

A three phase, three wire service has no neutral conductor, and may be supplied by either an open-delta or closed-delta transformer bank.

Three Phase, Four Wire, Wye

A three phase, four wire wye service has three phases and a neutral conductor where the phase to neutral voltages are nominally equal to each other, and the phase to phase voltage is equal totimes the phase to neutral voltage.

Three Phase, Four Wire Delta Service

A three phase, four wire delta service is a delta service which has one transformer centre tapped and connected to a neutral conductor (and grounded). In this case, where the voltage between any two phases is 240 V, the voltage between the grounded wire and either of the two phases from which it is centre tapped will be 120 V, and the voltage from the third phase to the grounded phases will be 208 V.

Specification Limit

The maximum permissible error permitted for a meter’s performance characteristic.

Test Link

A means to totally or partially isolate the voltage circuit from the current circuit of a meter.

Test Mode

A mode of operation which facilitates meter accuracy testing by introducing shorter test periods and/or greater resolution of readings.

Test Value (ei)

The result of a measurement after correction for any known systematic errors, at test point “i”.

Thermal Stability

A meter is considered to have reached thermal stability following a change in temperature, when the metrological characteristics of the meter have not changed by more than ±0.2% over a 10 minute interval.

Transformer

See instrument transformer.

Transformer (Primary) Rated Meter

A transformer-type meter which indicates or records the primary quantity being measured by using specific instrument transformer ratios.

Transformer-Type Meter

A meter designed to be used with instrument transformers.

Type

The designation assigned to a meter or device by the manufacturer for the purpose of distinguishing its particular design and construction from other designs, models or patterns. Such type designation shall embrace only those ranges and ratings that are essentially similar in appearance and performance.

Var Hour Meter

An integrating instrument which measures reactive energy in var hours or in suitable multiples thereof.

Verification

The process by which an approved meter is evaluated for compliance to the metrological, technical and administrative requirements specified in the Act, Regulations and these Specifications.

Volt Ampere Hour Meter

An integrating instrument which measures apparent energy in volt ampere hours or in suitable multiples thereof.

Voltage Transformer

An instrument transformer intended to have its primary winding connected across circuit with the voltage to be measured.

Watt Hour Meter

An integrating instrument which measures active energy in watt hours or in suitable multiples thereof.

Zero Load

A condition of null current or energy passing through the meter to the load being measured.

5.0 Administrative Requirements

5.1 General

5.1.1 Verification and reverification is intended to confirm that a meter conforms to all of the performance and non-performance requirements of an approved pattern (design, features, functions, marking, etc.). The extent of verification or reverification inspections shall be as specified in these specifications and any additional requirements authorized by Measurement Canada (MC) in regards to these specifications. Although the application of these requirements allow for verification and reverification of electricity meters the owner of the meter remains legally responsible for ensuring meters compliance with the statute and related MC policies and programs. Meter owners shall also subject meters to market place monitoring programs established by MC.

5.1.2 Any meter that fails to meet a performance or non-performance requirement, or that possesses a defect which could affect its ability to meet specified requirements, shall be classified as nonconforming.

5.1.3 All meter conformity tests shall be performed in accordance with documented procedures that have been evaluated for technical adequacy by the relevant MC technical experts.

5.2 Administrative Requirements Related to Performance

5.2.1 Conditions for Testing

All conditions specified herein for testing shall be satisfied prior to the meter being evaluated for performance.

5.2.2 Measuring Function Accuracy Range of Accuracy Test

5.2.2.1

In principle, verification or reverification shall confirm the performance capabilities of each approved measurement function of a meter that may be used for the basis of establishing a charge for the consumption of electricity however, the extent of testing required for this purpose shall be based on meter design and the evaluations performed during the approval examinations.

5.2.2.2

Approved measurement functions that the meter owner has requested not to be verified shall be disabled. Such functions shall not be accessible by any means, including the meter display or meter communication ports, upon verification and sealing of the meter.

5.2.2.3

Where the meter design permits and as approved by MC, certain measurement function tests may be waived, if the function’s performance characteristics can be determined through other related tests. These functions shall be considered to have been verified upon completion of approved related tests.

5.2.2.4

The tests which may be waived during verification and/or reverification shall have been determined through the approval process.

5.2.2.5

Approval tests may also indicate that additional tests over and above standardized verification and/or reverification tests specified herein may be required.

5.2.3 Implicit Accuracy of Each Measurement Function

Although the decision regarding the acceptability of a measurement function’s accuracy is based upon results of tests at a few discrete points, all measurement functions shall be accurate to within specified limits throughout their respective measuring ranges.

5.2.4 Correction for Known Errors

The results of meter tests performed for the purpose of verification and reverification shall be corrected for all known systematic errors. These errors shall include the known errors of the calibration console.

5.2.5 Documentation of Errors

Each error determined for a meter at any test point shall be reported as a minimum to the nearest 0.1% for electromechanical meters and 0.01% for electronic meters.

5.2.6 Limits of Calibration

Although a test point error is considered acceptable if it does not fall outside the specification limit for that test point, this fact shall not imply that a meter may be intentionally calibrated to register with errors near the specification limits. The calibration target is the midpoint of the specification range.

5.3 Sampling Plan for the Inspection of Isolated Lots of Meters in Service

Meters in service may be reverified as a lot by compliance sampling with use of a MC-authorized compliance sampling plan.

5.4 Verification and Reverification Methods

Meters may be verified or reverified by 100% inspection. Meters falling under the scope LMB-EG-04 may be sampled, however the sample meters shall meet the requirements for 100% inspection. In-service meters may be sampled in accordance to section 5.3, however the sample meters shall meet the requirements for 100% inspection. Meters that fall under the scope of Annex A shall be verified or reverified by 100% inspection or by sampling in accordance to that annex.

5.5 Verification Seal and Marking Requirements

All meters examined and determined to meet the verification or reverification requirements, shall have suitable verification markings affixed to physically indicate that the meter has been examined and found to meet the requirements of these Specifications. Meters verified or reverified shall be sealed in accordance with the requirements of the Electricity and Gas Inspection Act and Regulations and any specifications established thereunder.

5.6 Reverification Periods for Electricity Meters

All meters examined and determined to meet the verification or reverification requirements, shall be permitted to remain in service for the periods prescribed by Measurement Canada’s requirements for Reverification Periods for Electricity Meters and Metering Installations (reference 3.10). For meter that are not new and cannot be calibrated (i.e. MADT assessment is not made) the period for reverification will be as prescribed in reference 3.10 for reserviced meters.

5.7 Disposition of Meter with Questionable Accuracy

Any meter which has been mishandled or which is suspected of being in a state that does not conform with these Specifications shall not be put in service or continued in use until it has been reverified.

5.8 Requirements for Documentation of the Inspection Certificate or Record of Inspection

5.8.1 A certificate shall be issued for each meter inspected, verified, or reverified by an inspector or accredited organization who does not own the meter. The certificate shall contain all the information required pursuant to section 21 of the Electricity & Gas Inspection Regulations, as well as the applicable information listed in section 5.8.3 below.

5.8.2 A record of inspection shall be generated for each meter inspected, verified or reverified by an accredited organization who is also the owner of the meter. Such records shall contain all the information required pursuant to section 21 of the Electricity & Gas Inspection Regulations as well as the applicable information listed in section 5.8.3 below.

5.8.3 Pursuant to 5.8.1 and 5.8.2 above, the following information shall be included in the record of inspection or certificate of inspection as applicable:

  • Whether the meter is verified or reverified.
  • In the case of meters equipped with pulse initiators, the pulse value associated with the output pulse for each initiator as well as the pulse type or form (e.g. KYZ, 3-wire or 2-wire).
  • The conformance status of the meter with respect to these Specifications.
  • The year in which the meter will be due for reverification.
  • All operational parameters including the following:
    • meter multiplier (or multipliers , if different multipliers are applied for different functions)
    • voltage rating
    • current rating
  • Where the verification or reverification was performed by sampling methods:
    • the lot identification number
    • the number of meters in the lot
    • the values of all statistics determined from the errors of the sample meters
    • the conformance status
    • for compliance sample groups, the level and the extension period in years determined for the sample and its parent lot
  • Type of demand meter.
  • Frequency rating, if other than 60Hz.
  • Element configuration.
  • All electromechanical multifunction (combination) energy-demand meters with the demand component de-activated shall be noted on the inspection certificate.
  • A listing, or reference to a listing of any metrological parameters which were altered from the meters normal operating state in order to facilitate efficient verification.
  • A listing, or reference to a listing of approved functions for which the meter has been programmed.
  • Firmware revision.

5.8.4 The certificate or record of inspection shall serve as the formal record of the meter’s verification status and shall be maintained by the owner of the meter pursuant to the Act and Regulations.

5.9 Nameplate Markings

5.9.1 General

Meters shall be verified to ensure the location, legibility and markings meet the approval of type specification LMB-EG-07 reference 3.3 and any additional markings which may be required in the Notice of Approval.

6.0 Technical Requirements

6.1 General

6.1.1 Meter verification shall include inspections to ensure that the technical requirements specified in this section are complied with.

6.1.2 Meters shall be inspected for mechanical fitness and shall be free of any physical damage, defects in workmanship, or material deficiencies which could affect the meter's ability to comply with the requirements of these specifications during the meter's usage.

6.2 Mechanical Registers and Electronic Displays

6.2.1 Identification of Measurement Units

6.2.1.1

All meters shall be verified to ensure the presence of the applicable measurement unit identifiers for each approved energy or demand quantity which is displayed or registered. These measurement unit identifiers may also use the standard abbreviation for the measurement units.

6.2.1.2

Meters equipped with electronic displays may use a coded identifier to identify the measurement unit of approved measurement quantities, provided the coded identifiers can be traced to a table of codes of associated measurement units resident in the meter memory and displayable by the meter. The table of codes may be located on the meter nameplate or any other readily viewable location of the meter that is under the meter seal.

6.2.2 Meter Multipliers

6.2.2.1

All meters are required to identify the applicable meter multiplier, if this multiplier is other than unity.

6.2.2.2

For electromechanical energy meters, the meter multiplier shall be marked permanently and prominently, preferably in red, on the register or scale face.

6.2.2.3

For electromechanical demand or combination demand/energy meters, the meter multiplier shall be marked permanently and prominently, on either the register or nameplate, preferably in red.

6.2.2.4

Where an electromechanical meter has different multipliers for different measurement quantities, the applicable multiplier for each register and/or scale shall be marked in the proximity of the energy and demand units markings, in a manner which readily identifies the associated function multiplier.

6.2.2.5

For electronic meters, the meter multiplier shall be distinctly marked on the meter’s nameplate or electronic display.

6.2.3 Mechanical Registers

6.2.3.1 Register Markings
  1. Meters shall be verified to ensure that there are no markings on the register face except for the manufacturer’s name, trade mark, the direction of rotation indicator, register ratio, rotation index mark, multiplier, or marks pertaining to the reading of the register. Where the register face and nameplate are integral, the above requirement shall not apply but any markings shall not interfere with the reading of the register.
  2. It is not permissible to indicate above or below any individual dial or drum, the magnitude of either the complete indication or of the divisions.

6.2.4 Register Ratio - Induction Type Meters

  1. Induction type energy meters shall be verified to ensure that the register ratio is marked on the register in such a manner that it is legible without removing the register. If sufficient space is available, the register ratio shall be marked on the register faceplate.
  2. The register indication shall be strictly in accord with the result computed from the number of disc revolutions, the disc constant as given on the nameplate and with the multiplier.

6.2.5 Demand Registers

The driving pointer shall be examined to ensure that it is of a colour distinctly different from that of the driven pointer.

6.2.6 Electronic Displays

6.2.6.1 General
  1. Meters equipped with electronic displays and having programmable display parameters shall be clearly readable under normal conditions of use.
  2. Meters displaying date and time shall be in the all numeric format set forth in CAN3-Z234.4, unless otherwise clearly marked.

6.2.7 Register Resets

6.2.7.1 General
  1. The reset device shall be checked to ensure that it is not possible to reset (i.e. reset to zero) or modify energy registers with the meter sealed, unless the readings are stored in another sealed memory or register location for recall at any time. Only demand quantities shall be resettable on a sealed meter.
  2. For the case of mechanical demand registers, the device for resetting demand shall be such that, in its normal position, it does not affect either the maximum demand indicator or the driving element.
6.2.7.2 Resetting of Demand Registers

The peak demand reset event shall be verified to ensure that it:

  • resets the maximum demand indicator to zero (at no load conditions) or to the equivalent current demand position; and
  • increments any associated cumulative demand register by a value equal to the peak demand reading.

6.3 Data Retention Requirements

6.3.1 General

The data retention capabilities of meters having metered data, chronological data, or metrologically significant information which could be lost in the event of a power outage, shall be verified over a period of one minute, or any other period approved by MC , to ensure prevention of the loss of this information.

6.3.2 Carry-over Battery

Any device fitted with a carry-over battery shall be verified to confirm battery condition using one of the following means:

  • Confirm that the battery condition indicator indicates a good battery.
  • Measure battery voltage.
  • For meters equipped with batteries which cannot be accessed without breaking the meter seal, use manufacturers data on expected battery life and ensure that remaining battery life will be sufficient for the reverification period of the meter.

6.4 Electrical Requirements

6.4.1 Circuit Association Check

  1. All polyphase meters shall be subject to a circuit association test to ensure that each current circuit is associated with the correct voltage circuit
  2. This test is not required upon reverification if the meter seal has not been broken or damaged.

6.4.2 Pulse Initiator Requirements

  1. Meters having pulse initiators which represent functions that are not verified by other means shall be subject to verification at all applicable energy meter test points using the same specification limit.
  2. Pulse initiators which are used as the fundamental means for establishing time-related demand shall be verified for accuracy to specification limits of ±1.0% with a resolution of 0.1%.

6.4.3 Pulse Recorder

  1. Pulse recorder(s) or meters equipped with internal pulse recorder(s) shall be assessed to ensure that pulses are recorded accurately. Pulse recorders shall record total pulses accurately to a specification limit of ± 2 pulses when at least 100 pulses have been applied. Devices with multi-channel input and recording capabilities shall be assessed to the above criteria at each input channel.
  2. Devices intended for use in determining demand shall be subject to demand interval verification as per 6.5.5.
  3. Pulse recorders which convert pulses to energy values are subject to the requirements of multi-register metering (section 6.5.2), as well as pulse constants (section 6.5.7).

6.4.4 Reverse Operation

  1. Meters intended to be used for reverse flow energy shall be verified to ensure correct operation of the flow direction indicator.
  2. Meters equipped with pulse outputs shall be verified to ensure that detents prevent pulse output for the case of reverse operation.
  3. Each detented register on a meter shall be verified to confirm that there is no change in registration if the meter is connected to a load in the reverse direction.

6.4.5 Induction Type Var hour and Q hour Metering

Where an induction type watt hour meter is used with approved phase shifting transformers to meter var hours or Q hours, the meter shall be verified for the presence of markings indicating the units being measured. The meter shall also be verified for the presence of a marking to indicate that external phase shifting transformers are required. For the case of a watt hour meter that has been cross connected in order to meter Q hours the meter shall be verified for the presence of marking indicating that it has been cross connected and for the units being measured.

6.5 Verification of Advanced Meter Functions

6.5.1 Programmed Parameters

  1. Programmable metrological parameters and functions shall be verified to ensure that they are programmed correctly according to the meter owner provided specification and, if present, the information printed on the meter nameplate. This may be accomplished through a number of means, at the option of the meter verifier, depending on the function.
  2. These checks are not required upon reverification if the meter has not been reprogrammed and the meter seal has not been broken or damaged.

6.5.2 Multi-register Meter Functions

Meters equipped with multi-register functions shall be verified for the correctness of programmed information used to exercise switching of rate registers. This may be verified by one of the following means:

  • Comparing the programmed information stored in the meter against specified information provided by the owner of the meter.
  • Performing test(s) which assess each multi-register.
  • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

6.5.3 Prepayment Meters

In addition to all applicable administrative, technical and metrological requirements contained herein, prepayment meters shall also be assessed for the correctness of programmed parameters related to the prepayment function. The correctness of programmed parameters shall be verified by one of the following means:

  • Comparing the programmed information stored in the meter against specified information provided by the owner of the meter.
  • Performing test(s) which exercise the programmed parameters related to the prepayment function.
  • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

6.5.4 Multiplier

The meter multiplier shall be verified through one of the following means:

  • Examining the program in the meter, e.g. by using software or push-buttons.
  • Reading the multiplier on the meter display, if it is programmed into one of the meter’s display sequences.
  • Performing an accuracy test that makes use of a register to which the multiplier is applied, e.g. a demand or “dial” test. The resolution of this test shall be sufficient to determine the value of the multiplier to a resolution of 0.1%.
  • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

6.5.5 Demand Interval

The normal mode demand interval shall be verified through one of the following means:

  • Examining the program in the meter, e.g. by using software or push-buttons.
  • Reading the demand interval on the meter display, if it is programmed into one of the meter’s display sequences.
  • Performing a demand accuracy test.
  • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

Meters equipped with more than one demand interval, either for different demand quantities or multiple demand input channels (i.e. mass memory) shall have each interval assessed as above.

6.5.6 Demand Type

Demand Type refers to whether a meter is programmed for block/rolling block or exponential demand in normal mode. This shall be verified through one of the following means:

  • Examining the program in the meter, e.g. by using software or push-buttons.
  • Reading the demand type on the meter display, if it is programmed into one of the meter’s display sequences.
  • Performing a demand test.
  • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

6.5.7 Pulse Constants

  1. Pulse constants for pulse outputs (e.g. KYZ) shall be verified to ensure correctness of the programmed value in relation to the pulse type and form.
  2. Each pulse constant shall be verified for meters equipped with more than one pulse output and have pulse constants which are separately programmable. If a single programmed parameter determines the pulse constant for all pulse outputs, then only a single check is required. The pulse constant shall be verified through one of the following means:
    • Examining the program in the meter, e.g. by using software or push-buttons.
    • Reading the pulse rate on the meter display, if it is programmed into one of the meter’s display sequences.
    • Performing an accuracy test on one of the pulse outputs. This test may also be used to verify the corresponding energy function.
    • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

6.5.8 Pulse Output Detent

  1. Detent setting shall be verified on meter’s having pulse outputs with programmable detent.
  2. The detent of each output shall be verified for meters equipped with more than one pulse output and which have detents that are separately programmable. If a single programmed parameter determines the detent for all pulse outputs, then only a single check is required.
  3. The pulse detent shall be verified through one of the following means:
    • Examining the program in the meter, e.g. by using software or push-buttons.
    • Reading the detent setting on the meter display, if it is programmed into one of the meter’s display sequences.
    • Applying energy to the meter in the reverse direction relative to the direction of the pulse output, and confirming that no pulses are generated.
    • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

6.5.9 Programmable Register Detent

  1. Detent setting shall be verified on meters having registers with programmable detent.
  2. The detent of each register shall be verified for meters equipped with more that one register having detents that are separately programmable. If a single programmed parameter determines the detent for all registers, then only a single check is required.
  3. The programmable register detent shall be verified through one of the following means:
    • Examining the program in the meter, e.g. by using software or pushbuttons.
    • Reading the detent setting on the meter display, if it is programmed into one of the meter’s display sequences.
    • Applying energy to the meter in the reverse direction relative to the direction of the register, and confirming that there is no change in registration.
    • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

6.5.10 Loss Compensation

The loss compensation factor(s) in meters equipped with loss compensation shall be verified through one of the following means:

  • Examining the program in the meter, e.g. by using software or push-buttons.
  • Reading the loss compensation factor on the meter display, if it is programmed into one of the meter’s display sequences.
  • Performing an accuracy test that makes use of a register to which the loss compensation factor is applied, e.g. a demand or “dial” test. The resolution of this test shall be sufficient to determine the value of the multiplier to a resolution of 0.1%.
  • Other means that the meter verifier can demonstrate are valid and are approved by MC may be used.

6.6 Firmware Verification

Meter firmware shall be identical to a version(s) identified in the notice of approval or applicable modification acceptance letter(s) (MAL).

7.0 Metrological Requirements

7.1 General

  1. The requirements including test points and specification limits provided in this document shall be applied in conjunction with procedures either issued or accepted by MC.
  2. MC may establish additional test points and procedures as may be required for specific meter types.
  3. Unless otherwise noted the specification limits specified in this document are provided in terms of % relative error.
  4. Meters shall be fully assembled and calibrated before undergoing verification or reverification tests. Removal of the meter cover or access to sealable components, adjustments, or reprogramming during the verification process is permitted only when test procedures used have been issued or accepted by MC.
  5. All verification tests for accuracy of energy functions shall be determined to a minimum resolution of 0.1% for electromechanical meters and 0.01% for electronic meters unless otherwise stated.
  6. The errors for exponential responding demand meters shall be determined after the test load has been applied for three full demand response periods.

7.2 Reference Conditions for Metrological Requirements

Except as otherwise stated, the following reference conditions shall apply to all metrological requirements:

  • The ambient temperature shall be 23°C ± 5°C.
  • All voltage circuits shall be connected in parallel and all current circuits shall be connected in series assisting.
  • Before conducting any tests for the purpose of ascertaining meter performance, meters shall be warmed up as specified by the manufacturer up to a maximum of two hours.
  • The meter or device shall be in its normal working condition or in a mode approved for verification or reverification. Except where the nature of the test requires otherwise, all registers, transmitting contacts, detents, etc., shall be operating in the normal state. For cyclometer-type registers, only the fastest moving counter shall be turning.
  • The meter shall be installed during test such that the working position of the meter is within ± 3° of the front-to-back and side-to-side vertical planes. This requirement is applicable to electromechanical integrating meters or other meter types having accuracy which may be effected by tilt.
  • For the purpose of setting the test loads, all test points shall be within ±2.0% of the established test current, nominal voltage, and test load.
  • Power factor set points shall be within ±2.0 degrees of that specified for the test, and unless otherwise specified, shall be in the lag condition.
  • Unless otherwise specified, meters shall be evaluated at their nominally rated nameplate voltage.
  • Unless otherwise specified, meter test loads are established as a percentage of the maximum current rating (Imax) for the meter. Transformer type meters having a meter Imax of 10 amperes or greater and intended to be installed with transformers having a secondary rating of 5 amperes shall be evaluated using a value for Imax of 10 amperes.

7.3 Performance Requirements

7.3.1 General

Unless otherwise stated, each function of an electricity meter shall comply with the requirements set out in section 7.3, as applicable.

7.3.2 Electromechanical Meters

7.3.2.1 Zero Load Performance
  1. Energy meters shall be subjected to a zero load test, with a load of zero current and nominally rated voltage.
  2. The disk of an electromechanical meter shall be stopped or it shall not exhibit one complete revolution of its disk in a ten minute period.
7.3.2.2 Comparative Registration

Electromechanical meters shall be subjected to a comparative registration test (dial test). The specification limit is zero error relative to the disc, tested to a resolution of 3.0%.

7.3.2.3 Electromechanical Energy Meters, General

7.3.2.3.1 Single Phase 1 and 1½ Element Energy Meters

All single phase, single element, and one and one-half element, energy meters shall be evaluated at the test points and specification limits identified in table 7.1.

Table 7.1

Energy Tests: Single Phase, 1 Element and 1½ Element Meters
Test Configuration Current Power Factor Pf Specification Limit
Series Test 25% Imax 1.0 ±1.0%
Series Test 25% Imax 0.5
Series Test 2.5% Imax 1.0

Notes: Reverification tests at 0.5 Pf test are not required for magnetic suspension, single phase 1 and 1½ element energy meters.

Reverification tests at 0.5 Pf test are required for magnetic suspension, single phase 1 and 1½ element combination energy-demand meters.

7.3.2.3.2 Polyphase 2½ Element Wye Energy Meters

Polyphase 2½ element wye meters shall be evaluated at the test points and specification limits identified in table 7.2.

Table 7.2

Energy Tests: Polyphase 2½ Element Wye Meters
Test Configuration Current Power Factor Pf Specification Limit
Wh, VAh varh 1 Qh 1
Series Test 25% Imax 1.0 0.5 0.5 ±1.0%
Series Test 2.5% Imax 1.0 0.5 0.5
Each element 50% Imax 1.0 0.5 0.5
Each element 50% Imax 0.5 0.866 1.0
Split coil element 2 50% Imax 1.0 0.5 0.5

Notes:

  1. Var hour and Q hour meters that operate on the crossed phase principle shall be tested as watt hour meters.
  2. The split coil element test is not required on reverification.

7.3.2.3.3 Polyphase 2 Element, 2½ Element Delta, and 3 Element Energy Meters

Polyphase 2 element, 2½ element delta, and 3 element energy meters shall be evaluated at the test points and specification limits identified in table 7.3.

Table 7.3

Energy Tests: Polyphase 2 Element, 2½ Element Delta, and 3 Element meters
Test Configuration Current Power Factor Pf Specification Limit
Wh, VAh varh 1 Qh 1
Series Test 3 25% Imax 1.0 0.5 0.5 ±1.0%
Series Test 3 2.5% Imax 1.0 0.5 0.5
Each Element 2 25% Imax 1.0 0.5 0.5
Each Element 2 25% Imax 0.5 0.866 1.0
Each Element 2 (2½ element 4-wire Delta only) 2.5% Imax 1.0 0.5 0.5

Notes:

  1. Var hour and Q hour meters that operate on the crossed phase principle shall be tested as watt hour meters.
  2. The tests for each element of 2½ element 4-wire Delta meters shall be applied to:
    • the 2-wire element.
    • the 3-wire element in series.
  3. The series test for 3 element 4-wire Delta meters shall be conducted at the rated voltage of the lower rated potential coil. The individual element tests shall be conducted at the rated voltage of the respective potential coil.

7.3.2.3.4 Electromechanical Bi-directional Energy Meters

Electromechanical bi-directional energy meters shall be verified for each direction of energy flow. The test points and specification limits shall be as specified in tables 7.1 - 7.3 as applicable.

7.3.2.4 Electromechanical Demand Meters

7.3.2.4.1 General

  1. Thermal demand meters shall be tested for hysteresis (grease memory) by manually resetting the driven demand pointer a minimum of two major scale divisions and holding for a maximum of three seconds. After removing the demand reset mechanism, the driven demand pointer shall not move up scale more than 1.0% F.S. (Full Scale).
  2. Thermal demand meters shall be tested for pull-back after the demand test load is removed. The driven pointer shall not move down scale by more than 1.0% F.S.
  3. A thermally stable electromechanical thermal demand meter shall be evaluated to ensure that zero load is registered to within 1/32 inch of true zero.
  4. For the purpose of evaluating thermal demand errors determined at the test points indicated in tables 7.4 and 7.5 readings of the driven pointer shall be taken only after the driving pointer has disengaged.

7.3.2.4.2 Electromechanical 1 and 1½ Element Thermal Demand Meters

Single phase one element and 1½ element electromechanical thermal demand meters shall be evaluated at the test points and specification limits identified in table 7.4.

Table 7.4

Demand Tests: Electromechanical 1 and 1½ Element Thermal Demand Meters
Test Configuration Test Point Power Factor Pf Specification Limit
Series test 66.6% F.S. 1.0 ±1.5% F.S.
VA only: Series test 66.6% F.S. 0.5 ±1.5% F.S.
Any one element 20% F.S. 1.0 ±1.5% F.S.

7.3.2.4.3 Electromechanical 2, 2½ and 3 Element Thermal Demand Meters

Polyphase two element, 2½ element and three element electromechanical thermal demand meters shall be evaluated at the test points and specification limits identified in table 7.5.

Table 7.5

Demand Tests: Electromechanical 2, 2½ and 3 Element Thermal Demand Meters
Test Configuration Test Point Power Factor Pf Specification Limit
Series test 66.6% F.S. 1.0 ±1.5% F.S.
VA only: Series test 66.6% F.S. 0.5 ±1.5% F.S.
2 el: Any one element 20% F.S. 1.0 ±1.5% F.S.
3 el: Any two elements 20% F.S. 1.0 ±1.5% F.S.
2½ el: Each single element (delta meters) 20% F.S. 1.0 ±1.5% F.S.
2½ el: Each single element (wye meters) 16.6% F.S. 1.0 ±1.5% F.S.

7.3.2.4.4 Electromechanical Integrating Demand Meters

Where the demand pointer is driven by the meter disc, one series test shall be performed at 66.6% F.S., 1.0 Pf. The specification limit for this test is ±1.5% F.S.

7.3.2.4.5 Accuracy of Demand Interval

The demand interval for electromechanical block interval demand meters shall be within ±1.0% of the set interval.

7.3.3 Electronic Meters

7.3.3.1 Zero Load Performance

7.3.3.1.1

Electronic meters shall be subject to a zero load verification test performed with zero current in all circuits, and any rated voltage.

7.3.3.1.2

Meters may be evaluated for zero load performance using one of the methods outlined in (a) to (d) below. The duration of the evaluation test shall be determined based on a hypothetical load of 0.05% Imax at the test voltage and the test condition described in (a) to (d) as applicable. No registration is permitted for the duration of the tests performed in (a) to (d) below.

  • Demand Test: The duration of the test shall be at least one complete demand interval, or in the case of exponential demand three time constants. However, a demand test may be used only if the demand register has sufficient resolution to indicate a non-zero value at the load described in 7.3.3.1.2.
  • Pulse output or disk revolution simulator: The minimum duration of the test shall be the amount of time that would be required to obtain one pulse or disk revolution at the load described in 7.3.3.1.2.
  • Energy register Test: The minimum duration of the test shall be the amount of time that would be required to register a non-zero value at the load described in 7.3.3.1.2., based on the resolution of the energy register.
  • Other means such as instantaneous demand, that the meter verifier can demonstrate are valid and are approved by MC.
7.3.3.2 Accuracy Requirements

7.3.3.2.1

Electronic energy meters are to be programmed with the watthour function and shall be verified for each applicable energy function at the test points found in table 7.6 below.

Table 7.6

Energy Tests: Electronic Energy Meters
Test Configuration Current Power Factor Pf Specification Limit
Wh VAh Varh Qh
Series Test 1 25% Imax 1.0   0.5 0.5 ±1.00%
Series Test 1 25% Imax 0.5 0.5 0.866  
Individual Elements 1, 2 25% Imax 0.5      
Series Test 1 2.5% Imax 1.0      

Notes:

  1. The series test for 2 ½ and 3 element 4-wire Delta meters shall be conducted at the nameplate rated voltage. The individual element tests shall be conducted at the rated voltage of the respective potential coil.
  2. Individual element testing is not required for 1 and 1 ½ element meters.

7.3.3.2.2

Electronic demand meters shall be evaluated for all applicable demand functions identified in table 7.7 except as noted in (1) below. The 50% Imax test load shall be used except where a 25% Imax test load can be shown to provide a 0.1% resolution of reading, in which case either test point may be used.

Table 7.7

Demand Tests Points for Electronic Demand Meters
Test Configuration Current Power Factor Pf Specification Limit
W VA 1 Var 1
Series Test 50% Imax 0.5 0.5 0.866 ±1.00%
OR in accordance with 7.3.3.2.2 above
Series Test 25% Imax 0.5 0.5 0.866 ±1.00%

Note: Meters which have been assessed for VAh and/or Varh functions, and the Watt demand function, are not required to be assessed for their respective VA and/or Var demand functions.

7.3.3.2.3 Meters with Multiple or Auto-ranging Voltages

Electronic meters which are capable of operating at multiple voltages shall be verified with all elements in series/parallel configuration at one additional nominal service voltage using a previously verified current and power factor test point (i.e. energy or demand).

7.3.3.2.4 Voltage Squared Hour Meters

Meters which are capable of metering voltage squared hours shall be evaluated at 95% and 105% of the nominal nameplate voltage. The specification limit for these V2 h tests is ±1.00%.

7.3.3.2.5 Ampere Squared Hour Meters

Meters which are capable of metering ampere squared hours and have not been evaluated for the watt hour function, shall be evaluated at 2.5% Imax and 25% Imax. All other ampere squared hour meters may be evaluated at only one convenient test point which is at or greater than 25% Imax. The specification limit for these I2 h tests is ±1.00%.

7.3.3.2.6 Electronic Demand Meter Type

Each demand type (exponential, block, etc.) which has been programmed and not otherwise verified shall be verified in accordance with the requirements of section 7.3.3.2.2.

7.3.3.2.7 Meters Equipped with Gain Switching Circuits

Meters which are equipped with gain switching circuits shall be tested at one test point in each gain switching range. This may require additional test points for the case of meters having gain ranges not exercised by the standard test points. The additional test points within the various gain ranges of the meter shall be as established within procedures, Notices of Approvals or other official documentation as approved by MC.

7.3.3.2.8 Electronic Bi-directional Energy Meters

Electronic bi-directional energy meters shall be verified for all of the applicable tests in the delivered direction and at the test points specified in table 7.8 as applicable for the received direction.

Table 7.8
Test Configuration Current Power Factor Pf Specification Limit
Wh VAh Varh
Series Test 25% Imax 0.5 0.5 0.866 ±1.00%

7.3.4 Combination Electromechanical-Electronic Meters

  1. Combination electromechanical-electronic meters which have the disk of the electromechanical induction portion of the meter monitored electronically to provide approved metering functions shall be verified as follows:
    • for each approved energy function provided electronically the requirements of section 7.3.2 shall apply.
    • for each approved demand function provided electronically the requirements of section 7.3.3 shall apply.
  2. Combination electromechanical-electronic meters which have electromechanical metering elements and electronic metering elements which are independent of each other shall be verified as two independent meters. The electromechanical portion of such devices shall be verified in accordance with the applicable requirements of section 7.3.2 and the electronic portion of such devices shall be verified in accordance with the applicable requirements of sections 7.3.3.

8.0 Revision

8.1 The purpose of revision 1 is to remove the Testing facilities requirements, which were identified under the reduction initiative as being adequately addressed in section 19 of the Act.

8.2 The purpose for revision 2 is to remove remove the Nameplate requirements, which were identified under the reduction initiative as being adequately addressed in the approval specification and the notice of approval where additional markings may be required.

8.3 The purpose of revision 3 is to add requirements for sampling of electronic polyphase and demand meters.

8.4 The purpose of revision 4 is to add requirements for sampling of electro-mechanical energy meters.

Alan E. Johnston
President
Measurement Canada

Annex - A Acceptance Sampling and 100% inspection requirements

A.1 Scope

This annex specifies the requirements for acceptance sampling and 100% inspection of electronic and electro-mechanical meters.

A.2 Applicability

A.2.1 The requirements of this section are applicable to all:

  • electronic meters of section 7.3.3 which include, single phase, network and polyphase, self contained and transformer type energy meters (Wh, VAh, Varh and Qh), demand meters (Watts, VA, Var), and loss meters (V2 h, I2 h) with or without advanced functions; and
  • electro-mechanical meters of section 7.3.2 which include, single phase, network and polyphase, self contained and transformer type energy only meters (Wh, VAh, Varh and Qh).

A.2.2 This annex states the requirements for verification and reverification when the test or measurement result is subject to uncertainty, in accordance to the requirements of MC specification S-S-02 (reference 3.7).

A.3 General

A.3.1 Meters shall be verified or reverified in accordance to all of the applicable requirements in this document and as amended by this annex.

A.3.2 In general for the purpose of verification, test results for the following quality characteristics shall be treated as non-performance observations for functionality verification (i.e. pass/fail) of electronic meters. The following list as applicable, is not exhaustive and is not intended to include all the possible combinations of non-performance attributes to be inspected within a quality system:

  • Data retention capabilities
  • Carry-over battery condition
  • Pulse recording operation
  • Validation of programmed parameters
  • Multiplier verification
  • Pulse constant verification
  • Pulse output detent operation
  • Loss compensation factors and/or function
  • Zero load performance / creep test verification
  • Phase association verification
  • Confirmation of approved firmware
  • Mechanical integrity confirmation
  • Multi-register metering function
  • Demand reset operation
  • Demand type verification
  • Demand interval verification

A.3.3 The following quality characteristics shall be treated as non-performance observations for functionality verification (i.e. pass/fail) of electro-mechanical meters. The following list as applicable, is not exhaustive and is not intended to include all the possible combinations of non-performance attributes to be inspected within a quality system.

  • Multiplier verification
  • Pulse constant verification
  • Pulse output detent operation
  • Zero load performance/ Creep test verification
  • Phase association verification
  • Mechanical integrity confirmation
  • Multi-register metering function
  • Comparative registration verification / Dial test
  • Register markings (ratio)

A.4 Symbols and Abbreviated Terms

k

multiplier calculated to provide specified coverage for the uncertainty of a measurement

ei

test value

uci

combined standard uncertainty of ei

LSL

lower specification limit

USL

upper specification limit

MADT

mean absolute deviation from target

UMADT

Upper MADT specification limit

CSL1

compressed specification limits for type 1 marginal conformities (LQ = 3.15%)

CSL2

compressed specification limits for type 1 marginal conformities (LQ = 8.0%)

LCSL1

lower compressed specification limit (LQ = 3.15%)

LCSL2

lower compressed specification limit (LQ = 8.0%)

UCSL1

Upper compressed specification limit (LQ = 3.15%)

UCSL2

Upper compressed specification limit (LQ = 8.0%)

A.5 Limits of Error and Conformity Determination

A.5.1 The specification limit is ±1.00% and the minimum coverage criterion for the extended measurement result is at least 99% coverage. For the purpose of 100% inspection, conformity shall exist if all of the inequalities below are satisfied. For meters which are not new and cannot be calibrated, conformity shall exist if inequalities in sub clauses (i) and (ii) are satisfied.

  • ei - k uci ≥ LSL
  • ei + k uci ≤ USL and
  • mean ( |ei| ) ≤ 0.50 (USL)
    • where, k = 3.0000 and uci is determined in accordance to the requirements of MC Specification S-S-02 (reference 3.7)

Note 1: The MADT per A.5.1(iii) is calculated from all observations identified in A.5.2, below. The calculation method is to first determine the absolute value of each error, ei, then determine the mean of those values.

Note 2: The definition of new meter identified in A.5.1 above is as defined in bulletin E-26 reference 3.10, also see section 5.6 for applicable reverification periods.

A.5.2 For single phase, polyphase and network electronic meters the MADT is determined using the unweighted mean of all Wh energy observations at unity and 0.5 power factor.

A.5.3 Conformity shall be determined using a one-stage procedure in accordance to the requirements of MC specification S-S-02 (reference 3.7).

A.5.4 Measurement results shall be reported in accordance with S-S-02 (reference 3.7).

A.6 Acceptance Sampling Inspection for Electronic and Electro-mechanical (energy only) Meters

A.6.1 Devices may have their conformity evaluated by 100% inspection or, where the prerequisites of MC Specification S-S-03 (reference 3.8) have been and continue to be met, by sampling inspection in accordance with the requirements of MC Specification S-S-04 (reference 3.9).

A.6.2 A lot of meters submitted for acceptance sampling shall not contain a mixture of self contained and transformer type meters. As well, meters in the lot shall be homogeneous with respect to the following:

  • manufacturer and model, unless otherwise authorized by MC in accordance with clause A.6.3.
  • voltage or voltage range.
  • maximum current rating.
  • configuration with respect to number of elements, wye, delta or auto configuration.
  • units of measure.
  • firmware version that is identified as being homogeneous by the manufacturer (not applicable to electro-mechanical meters).
  • frequency rating.
  • same model or type of telemetering device (if so equipped), unless otherwise authorized by MC in accordance with clause A.6.3.
  • demand type, unless otherwise authorized by MC in accordance with clause A.6.3. (not applicable to electro-mechanical meters)
  • permissible batch types:
    1. new and/or renewed meters produced within a six-month period; or,
    2. previously-verified meters which have all been reconditioned (and/or repaired) and re-calibrated within a six-month period.

A.6.3 If an accredited organization wishes to combine, in one lot, various models or vintages of meters, and/or meters equipped with and without a telemetering device, or more than one telemetering device, the accredited organization shall submit a request to MC with accompanying documentation in support of their claim that these differing meters can be considered homogeneous for purposes of acceptance sampling.

A.6.4 For the purposes of sampling inspection, a conforming unit is as defined in these specifications, for performance and non-performance characteristics. A lot shall be sentenced based on the specification limit of ±1.00%. The criterion for the extended measurement result is at least 95% coverage. An accredited organization shall have the option to determine conformity using either a one-stage or two-stage procedure in accordance with the requirements of MC Specification S-S-02 (reference 3.7).

A.6.5 The compressed specification limit (CSL) values determined from the device’s performance specification limits are defined as follows:

Marginal conformity type Lower CSL Upper CSL
Type 1 (LQ of 3.15%) LCSL1 = 0.8350 (-1.00) = -0.8350 UCSL1 = 0.8350 (1.00) = 0.8350
Type 1 (LQ of 8.0%) LCSL2 = 0.6797 (-1.00) = -0.6797 UCSL2 = 0.6797 (1.00) = 0.6797
Type 2 (MADT)   UMADT = 0.5 (1.00) = 0.50

A.6.6 A device is classified as a marginally conforming unit if it has no nonconformity but exhibits performance falling outside the interval defined by the lower and upper CSL values (type 1 marginally conforming) or has an MADT value exceeding the MADT limit (type 2 marginally conforming).

A.6.7 The conformity, marginal conformity, or nonconformity of the device’s performance shall be determined in accordance with the requirements of S-S-02 (reference 3.7) and the following classification criteria based on the device’s relative error (ei), applied in the order presented below. For meters which are not new and cannot be calibrated, the conformity, marginal conformity, or nonconformity determination is applied to sub clauses (a), (b), (c) and (e).

  • nonconforming if ei + k uci > USL , or ei - k uci < LSL
  • marginally conforming type 1 if ei + k uci > UCSL1 or ei - k uci < LCSL1
  • marginally conforming type 1 if ei + k uci > UCSL2 or ei - k uci < LCSL2 (optional under sampling inspection)
  • marginally conforming type 2 if the mean ( |ei| ) > UMADT
  • conforming otherwise
    • where, k = 1.6449, uci is determined in accordance to the requirements of MC Specification S-S-02 (reference 3.7). MADT is determined in accordance with A.5.2

A.6.8 Measurement results shall be reported in accordance with S-S-02 (reference 3.2).

A.7 Outgoing Quality Requirements

The outgoing quality standards for meter quality under both 100% inspection and sampling inspection are:

  • No inspected meters shall be permitted to be placed in service with a result which is not contained within the 100% Inspection specification limits specified in subsections A.5.1.
  • No meters shall be permitted to be placed in service with one or more nonconformities or defects. (Note: The accredited organization shall be responsible for deciding which types of quality characteristic deficiencies are to be identified as a defect.)
  • Subject to a) and b) above, sample meters are considered acceptable regardless of the status of the lot.
  • The outgoing quality requirements shall be met for the product of the associated limiting quality (LQ) value and the lot size, as specified in S-S-03 (reference 3.8) or S-S-04 (reference 3.9) for type 1 and type 2 marginal conformities.
  • For meters which only undergo 100% inspection, the outgoing quality requirements of section A.7(d) are considered as being met if the 100% inspection requirements specified in section A.5 are met.

A.8 Disposition of Nonconforming Meters

A.8.1 For small lots inspected by 100% inspection or larger lots inspected but not accepted by sampling, nonconforming meters and excessive marginally conforming meters shall be removed or repaired to ensure the outgoing quality standards of section A.7 are met.

A.8.2 Individual non-conforming or defective meters may be resubmitted for inspection only after their deficient characteristics have been corrected.

A.8.3 Unacceptable lots may be resubmitted for inspection only after the meter owner or his agent has re-examined all meters and removed or corrected all non-conforming or defective meters. Re-inspection shall include evaluation of all quality characteristics where the non-acceptance is due to performance characteristics, or, for all other types of nonconformities and defects, evaluation of the characteristic(s) causing lot non-acceptance.