3.2.19 constant for electromechanical watt-hour meters value expressing the relation between the energy registered by the meter and the corresponding number of revolutions of the rotor
General definitions
An electromechanical meter operates by having fixed coils interact with currents induced in a moving conducting element, typically a disk This interaction results in movement that is proportional to the energy being measured, as defined in EN 62052-11, section 3.1.1.
3.1.2 static meter meter in which current and voltage act on solid state (electronic) elements to produce an output proportional to the energy to be measured [EN 62052-11, 3.1.2]
3.1.3 watt-hour meter active energy meter instrument intended to measure active energy by integrating active power with respect to time [IEV 313-06-01]
3.1.4 direct connected meter meter intended for use by direct connection to the electricity supply
3.1.5 transformer operated meter meter intended for use by connection via one or more external instrument transformers to the electricity supply
3.1.6 active power under periodic conditions, mean value, taken over one period T, of the instantaneous power p dt
NOTE 1 Under sinusoidal conditions, the active power is the real part of the complex power
NOTE 2 The SI unit for active power is the watt
3.1.7 apparent power product of the r.m.s voltage U between the terminals of a two-terminal element or two-terminal circuit and the r.m.s electric current I in the element or circuit:
NOTE 1 Under sinusoidal conditions, the apparent power is the modulus of the complex power
NOTE 2 The SI unit for apparent power is the volt-ampere
3.1.8 active energy the electrical energy transformable into some other form of energy [IEV 601-01-19]
3.1.9 power factor under periodic conditions, ratio of the absolute value of the active power P to the apparent power S
NOTE Under sinusoidal conditions, the power factor is the absolute value of the active factor
3.1.10 multi-rate meter energy meter provided with a number of registers, each becoming operative for specified time intervals corresponding to different tariff rates [IEV 313-06-09 modified]
A meter type for electromechanical meters refers to a specific design produced by a single manufacturer, characterized by consistent metrological properties, uniform construction of components that influence these properties, a fixed ratio of maximum current to reference current, and identical ampere-turns for the current winding at reference current, along with the same number of turns per volt for the voltage winding at reference voltage.
The type may have several values of reference current and reference voltage
Meters are designated by the manufacturer by one or more groups of letters or numbers, or a combination of letters and numbers Each type has one designation only
The type is defined by the sample meter(s) designated for type tests, with characteristics such as reference current and reference voltage selected from the values provided in the manufacturer's tables.
In cases where the calculated ampere-turns result in a non-integer number of turns, the product of the winding turns and the reference current may not match that of the representative sample meters for the type.
It is advisable to choose the next number immediately above or below in order to have whole numbers of turns
The number of turns per volt in the voltage windings may vary, but this difference should not exceed 20% compared to the sample meters that represent the type.
NOTE 3 The ratio of the highest to the lowest reference speed of the rotors of each of the meters of the same type shall not exceed 1,5
A meter type for static meters refers to a specific design produced by a single manufacturer, characterized by consistent metrological properties, uniform construction of both hardware and software components that define these properties, and a uniform ratio of maximum current to reference current.
The type may have several values of reference current and reference voltage
Meters are designated by the manufacturer by one or more groups of letters or numbers, or a combination of letters and numbers Each type has one designation only
The type is defined by the sample meter(s) designated for type tests, with characteristics such as reference current and reference voltage selected from the values provided in the manufacturer's tables.
NOTE 2 A specific meter design with identical elements in the current circuit may be suitable for more than one current range
3.1.13 reference meter a meter used to measure the unit of electric energy It is usually designed and operated to obtain the highest accuracy and stability in a controlled laboratory environment [EN 62052-11, 3.1.9]
Definitions related to the functional elements
3.2.1 metrologically relevant a function or property of the meter, subject to control by a legal metrology body
3.2.2 measuring element part of the meter which produces an output proportional to the energy [EN 62052-11, 3.2.1]
3.2.3 test output device (of an energy meter) device which can be used for determining the meter error
This device can be utilized with electromechanical induction meters by marking the disk, allowing an external photoelectric device to detect the mark's passage For static meters, it features an internal electronic pulse output device.
3.2.4 operation indicator device which gives a visible signal of the operation of the meter [IEV 314-07-13]
3.2.5 pulse wave that departs from an initial level for a limited duration of time and ultimately returns to the original level [EN 62052-11, 3.2.2.3]
3.2.6 pulse device (for electricity metering) functional unit for emitting, transmitting, retransmitting or receiving pulses, representing finite quantities, such as energy units [EN 62052-11, 3.2.2.4 modified]
3.2.7 pulse output device pulse output pulse device for emitting pulses [EN 62052-11, 3.2.2.5]
3.2.8 optical test output optical pulse output device that is used for testing the meter [EN 62052-11, 3.2.2.6]
3.2.9 electrical test output electrical pulse output device that is used for testing the meter [EN 62052-11, 3.2.2.7]
3.2.10 receiving head functional unit for receiving pulses emitted by an optical pulse output [EN 62052-11, 3.2.2.8]
3.2.11 memory (for static meters) element which stores digital information [IEV 314-07-10 modified]
3.2.12 non-volatile memory memory which can retain information in the absence of power [EN 62052-11, 3.2.3.1]
3.2.13 display device which displays the content(s) of (a) memory(ies) [IEV 314-07-11]
3.2.14 register the part of the meter which enables the measured value to be determined
An electromechanical or electronic device can store and display information, featuring both memory and display components A single electronic display may be utilized alongside multiple electronic memories to create various electronic registers.
3.2.15 current circuit internal connections of the meter and part of the measuring element through which flows the current of the circuit to which the meter is connected [EN 62052-11, 3.2.6]
The internal connections of the voltage circuit in static meters include components of the measuring element and the power supply, which is powered by the voltage from the circuit to which the meter is connected, as specified in EN 62052-11, section 3.2.7.
3.2.17 auxiliary device a device within the meter intended to perform a particular function additional to the basic metrology function, like tariff- and load control, or reception or transmission of data
3.2.18 auxiliary circuit elements and connections of an auxiliary device within the meter case intended to be connected to an external device [EN 62052-11, 3.2.8 modified]
The constant for electromechanical watt-hour meters represents the relationship between the energy recorded by the meter and the number of rotor revolutions, typically expressed in revolutions per kilowatt-hour (rev/kWh) or watt-hours per revolution (Wh/rev) as defined in EN 62052-11.
3.2.20 constant (for static watt-hour meters) value expressing the relation between the energy registered by the meter and the corresponding value of the test output
NOTE If this value is a number of pulses, the constant should be either pulses per kilowatt-hour (imp/kWh) or watt-hours per pulse (Wh/imp)
Definitions of mechanical elements
3.3.1 indoor meter meter which can only be used in areas offering additional protection against environmental influences (e.g in a house or in a cabinet) [IEV 314-07-20]
3.3.2 outdoor meter meter which can be used without additional protection in an exposed environment [IEV 314-07-21]
3.3.3 base back of the meter by which it is generally fixed and to which are attached the measuring element(s), the terminals or the terminal block, and the cover
NOTE For a flush-mounted meter, the meter base may include the sides of the case
A socket base equipped with jaws is designed to hold the terminals of a detachable meter and includes terminals for connecting to the supply line This socket can be configured as a single-position unit for one meter or as a multiple-position unit for two or more meters.
The cover enclosure on the front of the meter can be made entirely of transparent material or opaque material with windows, allowing visibility of the operation indicator and display.
3.3.6 case set that comprises the base and the cover [IEV 314-07-17]
3.3.7 accessible conductive part conductive part which can be touched by the standard test finger, when the meter is installed and ready for use [IEV 442-01-15 modified]
3.3.8 protective earthing earthing a point or points in a system or in an installation or in equipment, for purposes of electrical safety [IEV 195-01-11]
3.3.9 protective earth terminal terminal connected to accessible conductive parts of a meter for safety purposes [EN 62052-11, 3.3.7]
3.3.10 terminal block support made of insulating material on which all or some of the terminals of the meter are grouped together [IEV 314-07-18]
3.3.11 terminal cover cover which covers the meter terminals and, generally, the ends of the external wires or cables connected to the terminals [IEV 314-07-19 modified]
Definitions related to insulation
3.4.1 clearance the shortest distance through air between two conductive parts [IEV 604-03-60 modified]
3.4.2 creepage distance the shortest distance along the surface of a solid insulating material between two conductive parts [IEV 604-03-61]
3.4.3 hazardous-live-part live part which, under certain conditions, can give a harmful electric shock [IEV 195-06-05]
3.4.4 basic insulation insulation of hazardous-live-parts which provides basic protection
NOTE This concept does not apply to insulation used exclusively for functional purposes
3.4.5 supplementary insulation independent insulation applied in addition to basic insulation, for fault protection [IEV 195-06-07]
3.4.6 double insulation insulation comprising both basic insulation and supplementary insulation [IEV 195-06-08]
3.4.7 reinforced insulation insulation of hazardous-live-parts which provides a degree of protection against electric shock equivalent to double insulation
NOTE Reinforced insulation may comprise several layers, which cannot be tested singly as basic insulation or supplementary insulation
An insulating encased protective class I meter provides enhanced safety by ensuring that protection against electric shock is not solely dependent on basic insulation This type of meter includes an additional safety feature where accessible conductive parts are connected to the protective earthing conductor within the fixed wiring of the installation As a result, these conductive parts are designed to remain non-live even if the basic insulation fails.
NOTE This provision includes a protective earth terminal
An insulating encased meter of protective class II features a case made of insulating material that ensures protection against electric shock through more than just basic insulation This type of meter incorporates additional safety measures, such as double or reinforced insulation, and does not depend on protective earthing or specific installation conditions for safety.
Definitions of meter quantities
3.5.1 measurand particular quantity subject to measurement [VIM 2.6] [IEV 311-01-03]
3.5.2 current 3) ( I ) the electrical current flowing through the meter
3.5.3 starting current 3) ( I st ) the lowest value of the current at which the meter is declared to register active electrical energy at unity power factor (polyphase meters with balanced load)
3.5.4 minimum current 3) ( I min ) the lowest value of the current at which this European Standard specifies accuracy requirements At and above I min, up to I tr relaxed accuracy requirements apply
3.5.5 transitional current 3) ( I tr ) the value of the current at, and above which, up to I max full accuracy requirements of this European Standard apply
– for direct connected meters, 10 times the transitional current
NOTE 1 This value is the same as basic current, I b defined in EN 62052-11, 3.5.1.2
– for current transformer operated meters, 20 times the transitional current
NOTE 2 This value is the same as rated current, I n
3) The terms "voltage" and "current" indicate r.m.s values unless otherwise specified
3.5.7 rated current 3) ( I n ) in case of a transformer operated meter, the value of the current for which the meter has been designed
NOTE In case of transformer operated meters, the terms “reference current” and “rated current” are synonymous
3.5.8 maximum current 3) ( I max ) highest value of current at which the meter purports to meet the accuracy requirements of this European Standard [EN 62052-11, 3.5.2]
3.5.9 voltage 3) ( U ) the voltage of the circuit to which the meter is connected
3.5.10 reference voltage 3) ( U n ) value of the voltage in accordance with which the relevant performance of the meter is fixed
NOTE The reference voltage can take more than one value
3.5.11 frequency ( f ) the frequency in the circuit to which the meter is connected
3.5.12 reference frequency ( f n ) value of the frequency in accordance with which the relevant performance of the meter is fixed [EN 62052-11, 3.5.4]
3.5.13 measuring range range defined by two values of the measurand, within which the limits of the error of the meter are specified [≠ VIM 5.4]
NOTE An instrument can have several measuring ranges
3.5.14 class index a designation that identifies:
The meter must adhere to specific limits for percentage error under reference conditions, account for additional percentage errors caused by influencing factors, and meet the maximum permissible error standards during rated operating conditions.
– the set of critical change values caused by long term disturbances the meter shall comply with
NOTE A meter may be assigned to different class indexes for different rated operating conditions
3.5.15 percentage error percentage error is given by the following formula: × 100
= − energy true energy true meter the by registered energy error percentage
The true value of a measurement cannot be precisely determined; instead, it is represented by an approximate value accompanied by a specified uncertainty This uncertainty is linked to standards that are mutually accepted by both the manufacturer and the user, or to established national standards.
3.5.16 intrinsic error percentage error of a meter when used under reference conditions [≠ VIM 5.24]
NOTE This term is used in the "true value" approach
The additional percentage error of a meter, when compared to its intrinsic error for the same measurand, arises from the influence of a single quantity that takes on two specified values, one of which is the reference value This concept is outlined in the modified IEV 311-07-03 standard.
3.5.18 composite error percentage error calculated from the measured values of the intrinsic error and the additional percentage error due to influence quantities
NOTE For the influence quantities to be considered, and the calculation of composite error, see the relevant standard for particular requirements
3.5.19 maximum permissible error (MPE) extreme values of the composite error permitted by this European Standard [VIM 5.21 modified]
3.5.20 repeatability closeness of the agreement between the results of successive measurements of the same measurand carried out under the same conditions of measurement
NOTE 1 These conditions are called repeatability conditions
– the same measuring instrument, used under the same conditions;
Definitions of influence quantities
3.6.1 influence quantity any quantity, generally external to the meter, which may affect its working performance [IEV 311-06-01 modified]
3.6.2 reference conditions appropriate set of influence quantities and performance characteristics, with reference values, their tolerances and reference ranges, with respect to which the intrinsic error is specified [IEV 311-06-02 modified]
Rated operating conditions refer to the defined measuring ranges for performance characteristics and the specified operating ranges for influencing factors Within these conditions, the variations in operating errors of a meter are specified and determined, as outlined in [EN 62052-11, 3.6.7].
3.6.4 specified operating range range of values of a single influence quantity which forms a part of the rated operating conditions [EN 62052-11, 3.6.8]
The extended operating range refers to the extreme conditions that a meter can endure without sustaining damage or experiencing a decline in its metrological characteristics when it is later used under its rated operating conditions In this range, it is permissible to specify relaxed accuracy requirements.
The limit range of operation defines the extreme conditions that a meter can endure without sustaining damage or experiencing degradation in its metrological characteristics when it is later used under its rated operating conditions, as specified in EN 62052-11, section 3.6.10.
Non-operating meters must endure extreme storage and transportation conditions without sustaining damage or experiencing degradation in their metrological characteristics This ensures that they function correctly when later operated under their rated conditions, as outlined in EN 62052-11.
A disturbance is defined as an influence quantity that falls within the limits outlined in this European Standard but is outside the specified rated operating conditions of the meter If the rated operating conditions for a particular influence quantity are not specified, it is considered a disturbance.
3.6.9 electromagnetic disturbance any electromagnetic phenomenon which may degrade the performance of the meter [IEV 161-01-05 modified]
3.6.10 climatic environment the set of temperature ranges, humidity conditions, and intended location (indoor or outdoor) to which the meter may be exposed during its normal use
3.6.11 reference temperature ambient temperature specified for reference conditions [EN 62052-11, 3.6.6]
3.6.12 temperature coefficient ratio of the variation of the percentage error to the change of temperature which produces this variation [EN 62052-11, 3.6.6.1]
Thermal stability is achieved when the percentage error due to thermal effects remains below 1/10th of the allowable percentage error at reference conditions within a 20-minute timeframe, as outlined in [EN 62052-11, 3.6.13 modified].
3.6.14 critical change value the maximum acceptable value of the change in the measurement result caused by a disturbance
3.6.15 immunity (to an electromagnetic disturbance) the ability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance
NOTE For each kind of electromagnetic disturbance, the acceptable response is defined.
3.6.16 fundamental component (of a Fourier series) fundamental sinusoidal component of the Fourier series of a periodic quantity having the frequency of the quantity itself
NOTE For practical analysis, an approximation of the periodicity may be necessary
3.6.17 harmonic component sinusoidal component of a periodic quantity having a harmonic frequency
NOTE For practical analysis, an approximation of the periodicity may be necessary
3.6.18 harmonic order ratio of the frequency of any sinusoidal component to the fundamental frequency
NOTE The harmonic order of the fundamental component or the reference fundamental component is one
3.6.19 sub-harmonic component interharmonic component of harmonic order lower than one
NOTE In some applications sub-harmonic components are restricted to orders being reciprocal of integers
THD (abbreviation) the ratio of the rms value of the harmonic content of an alternating quantity to the rms value of the fundamental component of the quantity [IEV 551-17-06]
3.6.21 voltage dip a sudden reduction of the voltage at a particular point of an electricity supply system below a specified dip threshold followed by its recovery after a brief interval
NOTE 1 Typically, a dip is associated with the occurrence and termination of a short circuit or other extreme current increase on the system or installations connected to it
NOTE 2 A voltage dip is a two-dimensional electromagnetic disturbance, the level of which is determined by both voltage and time (duration)
3.6.22 short interruption a sudden reduction of the voltage on all phases at a particular point of an electric supply system below a specified interruption threshold followed by its restoration after a brief interval
NOTE Short interruptions are typically associated with switchgear operations related to the occurrence and termination of short circuits on the system or on installations connected to it
3.6.23 normal working position position of the meter defined by the manufacturer for normal service [EN 62052-11, 3.6.12]
Definitions of tests
The type test procedure involves conducting a series of tests on one or a limited number of meters of the same type, which possess identical characteristics as selected by the manufacturer This process is essential to ensure that the specific type of meter meets all the requirements outlined in the relevant standard for its class, as specified in EN 62052-11, section 3.7.1.
Definitions related to electromechanical meters
3.8.1 rotor moving element of the meter upon which the magnetic fluxes of fixed windings and of braking elements act and which operates the register [EN 62052-11, 3.8.1]
The driving element of the meter is the component responsible for generating torque through the interaction of its magnetic fluxes with the currents induced in the moving element Typically, this part consists of electromagnets along with their associated control devices, as outlined in [EN 62052-11, 3.8.2].
The braking element of the meter generates braking torque through the interaction of its magnetic flux with the currents induced in the moving element This component consists of one or more magnets along with their adjustment mechanisms.
3.8.4 frame part to which are affixed the driving elements, the rotor bearings, the register, usually the braking element, and sometimes the adjusting devices [EN 62052-11, 3.8.4]
The reference speed is defined as the nominal rotational speed of the rotor, measured in revolutions per minute (RPM), when the meter operates under reference conditions and carries a reference current at a unity power factor, as specified in EN 62052-11, section 3.8.5 (modified).
The reference torque is defined as the nominal torque value on the rotor when it is stationary, measured under reference conditions while carrying the reference current at a unity power factor, as specified in EN 62052-11, section 3.8.6 (modified).
3.8.7 vertical working position the position of the meter in which the shaft of the rotor is vertical [EN 62052-11, 3.8.7]
Abbreviations
ind inductive load / power factor cap capacitive load / power factor
Standard reference voltages
Standard currents and current ranges
Table 2 – Standard values of I tr , I ref and I n
Meters for Current Value of current
Connection through current transformer(s) I n ( = I ref ) 1 – 2 – 5
NOTE The value of I ref is given for information
The values of I st, I min, I tr, I n, and I max have to be chosen so, that the following relationships are met:
Meters for Class index A Class index B Class index C
* For class index B electromechanical meters, I min ≤ 0,4 I tr shall apply
When using a current transformer operated meter, it is essential to ensure that the rated current and measuring range align with the rated secondary current of the transformer According to EN 60044-1, current transformers are classified into accuracy classes 1.0, 0.5, 0.2, and 0.1, with a measuring range of 5% to 120% of the rated current, while classes 0.2S and 0.5S have a range of 1% to 120% The standard rated secondary currents for these transformers are 1 A, 2 A, and 5 A, with 5 A being the preferred choice Additionally, the meter's specified measuring range can encompass the ranges of current transformers with varying rated currents.
Standard reference frequency
Standard value for reference frequency is 50 Hz
General mechanical requirements
The manufacturer shall specify the mechanical environment the meter is intended for
NOTE 1 Meters are generally used in locations where levels of vibration and shock are of low significance
Meters shall be designed and constructed in such a way as to avoid introducing any danger in normal use and under normal conditions, so as to ensure especially:
– personal safety against electric shock;
– personal safety against effects of excessive temperature;
– protection against spread of fire;
– protection against penetration of solid objects, dust and water
To ensure durability, all components prone to corrosion in typical operating conditions must be effectively protected Protective coatings should resist damage from regular handling and exposure to air during normal use Additionally, outdoor meters must be capable of withstanding solar radiation.
NOTE 2 For meters for special use in corrosive atmospheres, additional requirements shall be fixed in the purchase contract (e.g salt mist test according to EN 60068-2-11)
The components shall be reliably fastened and secured against loosening
To reduce the risk of short-circuiting between live components and accessible conductive parts, the design of meters must prioritize minimizing potential hazards caused by accidental loosening or unscrewing of wiring and screws.
Case
Requirements
The meter must feature a sealed case that safeguards its internal metrologically relevant components, ensuring that access to these parts requires breaking the metrology seal or the case itself.
The cover shall not be removable without the use of a tool
The case shall be so constructed and arranged that any non-permanent deformation cannot prevent the satisfactory operation of the meter.
Mechanical strength tests of meter case
5.2.2.1 Spring hammer test (Test Ehb)
The mechanical strength of the meter case shall be tested with a spring hammer (test Ehb, see
The meter must be installed in its standard operational position, ensuring that the spring hammer impacts the outer surfaces of the meter cover, including the windows, as well as the terminal cover, with a kinetic energy of 0.2 J ± 0.02 J.
The test results are deemed satisfactory if the meter case and terminal cover remain undamaged, ensuring the meter's functionality and preventing access to live parts Minor damage that does not compromise protection against indirect contact or the intrusion of solid objects, dust, and water is considered acceptable.
The test shall be carried out according to EN 60068-2-27, under the following conditions:
– meter in non-operating condition, without the packing;
– duration of the pulse: 18 ms.
After the test, the meter shall show neither damage nor change of the information and shall operate correctly in accordance with the requirements of the relevant standard
5.2.2.3 Vibration test (sinusoidal) (Test Fc)
The test shall be carried out according to EN 60068-2-6, under the following conditions:
– meter in non-operating condition, without the packing;
– frequency range: 10 Hz to 150 Hz;
– f < 60 Hz, constant amplitude of movement 0,075 mm;
– number of sweep cycles per axis: 10
NOTE 1 The nominal transition frequency is 60Hz, for this test the actual crossover (transition) frequency is 58,1Hz
After the test, the meter shall show neither damage nor change of the information and shall operate correctly in accordance with the requirements of the relevant standard.
Window
For non-transparent covers, it is essential to include one or more windows made of durable transparent material These windows allow for easy reading of the display and observation of the operation indicator, if present, and must be designed to remain intact without breaking the seals.
Terminals - Terminal block(s) - Protective earth terminal
Terminals can be organized into terminal blocks that possess sufficient insulating properties and mechanical strength To meet these criteria, it is essential to conduct thorough testing of the insulating materials selected for the terminal blocks.
The terminal block must be designed to ensure that the meter meets insulation requirements and maintains appropriate clearance and creepage distances, even when subjected to deformation under rated operating conditions.
The material of which the terminal block is made shall be capable of passing the tests given in
EN ISO 75-2 for a temperature of 135 °C and a pressure of 1,8 MPa (Method A)
The holes in the insulating material, which form an extension of the terminal holes, shall be of sufficient size to accommodate also the insulation of the conductors
To ensure reliable and long-lasting connections, conductors must be securely attached to terminals to prevent loosening or overheating Screw connections that transmit contact force, as well as those that may be repeatedly tightened and loosened throughout the meter's lifespan, should be fastened into a metal nut.
All parts of each terminal shall be such that the risk of corrosion resulting from contact with any other metal part is minimized
Electrical connections shall be so designed that contact pressure is not transmitted through insulating material
For current circuits, the voltage is considered to be the same as for the related voltage circuit
NOTE The voltage and current circuits of a transformer operated meter are not considered to be electrically related.
To prevent accidental short-circuiting, terminals with varying potentials that are positioned closely together must be safeguarded This protection can be achieved through the use of insulating barriers It is important to note that terminals belonging to the same current circuit are regarded as being at the same potential.
The terminals, the conductor fixing screws or the external or internal conductors shall not be liable to come into contact with metal terminal covers
The protective earth terminal must be electrically bonded to accessible metal parts and, if possible, integrated into the meter base It should ideally be positioned next to its terminal block and accommodate a conductor with a cross-section equivalent to the main current conductors, with a minimum of 6 mm² and a maximum of 16 mm² for copper conductors Additionally, it must be clearly marked with the graphical symbol IEC 60417-5019, indicating protective earth (ground).
After installation, it shall not be possible to loosen the protective earth terminal without the use of a tool.
Terminal cover(s)
Meter terminals, when organized in a terminal block and lacking additional protection, must feature a distinct cover that can be sealed separately from the meter cover This terminal cover should fully enclose the terminals, conductor fixing screws, and, unless specified otherwise, an appropriate length of the external conductors along with their insulation.
Clearance and creepage distances
The clearance and creepage distances between any terminal of a circuit with a reference voltage exceeding 40 V and earth, as well as terminals of auxiliary circuits with reference voltages of 40 V or lower, must meet the specified minimum requirements.
– Table 4 for meters of protective class I;
– Table 5 for meters of protective class II
The clearance and creepage distances between terminals of circuits with reference voltages over 40 V shall not be less than stated in Table 4
The clearance between a metal terminal cover and the upper surface of the screws, when fully tightened with the appropriate conductor, must meet or exceed the values specified in Table 4.
Table 4 – Clearances and creepage distances for insulating encased meter of protective class I
Minimum clearances Minimum creepage distance
Voltage phase to earth derived from rated system voltage
Table 5 – Clearances and creepage distances for insulating encased meter of protective class II
Minimum clearances Minimum creepage distance
Voltage phase to earth derived from rated system voltage
The requirement of the impulse voltage test shall also be met (see 7.3.3).
Insulating encased meter of protective class II
A class II protective meter must feature a robust and continuous enclosure made entirely of insulating material, including the terminal cover, which protects all metal components except for small parts like name-plates, screws, suspensions, and rivets If these small parts can be accessed by a standard test finger as defined in EN 60529, they must be further insulated from live parts with supplementary insulation to prevent failures in basic insulation or loosening of live components Materials such as lacquer, enamel, ordinary paper, cotton, oxide film on metal, adhesive film, and sealing compounds are not considered adequate for supplementary insulation.
For the terminal block and terminal cover of such a meter, reinforced insulation is sufficient
A visual inspection for compliance with the conditions of this clause shall be made.
Resistance to heat and fire
The terminal block, terminal cover, and meter case must provide adequate fire safety by preventing ignition from thermal overload of live components in contact with them.
To comply therewith they shall fulfil the following test
The test shall be carried out according to EN 60695-2-10 and EN 60695-2-11, with the following temperatures:
– terminal cover and meter case: 650 °C ± 10 °C;
Contact with the glow wire can happen at any random location When the terminal block is integrated with the meter base, testing is only necessary on the terminal block.
Protection against penetration of dust and water
The meter shall conform to the degree of protection given in EN 60529:
– indoor meter: IP51, but without suction in the meter;
The tests shall be carried out according to EN 60529, under the following conditions: a) Protection against penetration of dust:
– meter in non-operating condition and mounted on an artificial wall;
– the test should be conducted with sample lengths of cable (exposed ends sealed) of the types specified by the manufacturer and terminal cover in place;
– for indoor meters only, the same atmospheric pressure is maintained inside the meter as outside (neither under- nor over-pressure);
Any ingress of dust shall be only in a quantity not impairing the operation of the meter An insulation test according to 7.3 shall be passed. b) Protection against penetration of water:
– meter in non-operating condition;
– second characteristic digit: 1 (IPX1) for indoor meters;
Any ingress of water shall be only in a quantity not impairing the operation of the meter An insulation test according to 7.3 shall be passed.
Display of measured values
The meter must include a register that allows consumers to read it visually without specialized tools, and it can be either electromechanical or electronic, featuring both memory and display It should be easily readable under typical usage conditions For electronic registers, the non-volatile memory must retain data for at least four months.
NOTE 1 Longer retention time of the non-volatile memory should be the subject of purchase contract
When multiple values are shown on a single display, it is essential to present the contents of all relevant memories clearly Each value must be distinctly identified, and for automatic sequencing displays, each billing register display should be maintained for at least 5 seconds.
The active tariff rate shall be indicated
When the meter is not energized, the electronic display does not need to be visible
The principal unit for the measured values shall be the kilowatt-hour (kWh), or the megawatt-hour (MWh) The principal unit shall be shown adjacent to the measured value
Electromechanical registers must feature indelible and easily readable markings The continuously rotating drum displaying the lowest values should be graduated and numbered into ten divisions, with each division further subdivided into ten parts to maintain reading accuracy Additionally, drums indicating a decimal fraction of the unit must have distinct markings when visible.
Every numerical element of an electronic display shall be able to show all the numbers from "zero" to
For testing purposes, the resolution can be increased to 0.01 times the principal unit or higher, allowing for the observation of critical change values.
The register shall be able to record and display, starting from zero, for a minimum of 4 000 h, the energy corresponding to maximum current at reference voltage and unity power factor
NOTE 2 Values higher than 4 000 h should be subject of purchase contract
The total quantity of electrical energy supplied must be displayed in a manner that cannot be reset during use, ensuring that the information used for payment calculations remains accurate and reliable.
NOTE 3 The regular roll over of the register is not considered as a reset.
Output device and operation indicator
General
The meter shall have a test output device capable of being monitored with suitable testing equipment
The test output must guarantee that accuracy tests can be conducted with a repeatability of one-tenth of the percentage error limits under reference conditions for the applicable class index at various test points.
NOTE See also Subclause 8.2 of EN 50470-2 and EN 50470-3
For devices with pulse output that may generate non-homogeneous pulse sequences, the manufacturer must specify the minimum number of pulses needed to achieve the desired repeatability.
For electrical test output, see EN 62053-31
If the test output is an optical test output then it shall fulfil the requirements according to 5.11.2 and 5.11.3
The operation indicator, if fitted, shall be visible from the front.
Mechanical and electrical characteristics
An optical test output shall be accessible from the front
The maximum pulse frequency shall not exceed 2,5 kHz
Modulated and unmodulated output pulses are permitted The unmodulated output pulses shall have the shape shown in Figure B.2
The pulse transition time, which includes both rise time and fall time, refers to the duration it takes for a signal to switch from one state to another, accounting for transient effects It is essential that this transition time does not exceed 20 microseconds, as illustrated in Figure B.2.
To prevent interference, the distance between the optical pulse output and adjacent optical devices, such as operation indicators, status indicators, or communication ports, must be adequately spaced.
An optimum pulse transmission is achieved when, under test conditions, the receiving head is aligned with its optical axis on the optical pulse output
The rise time given in Figure B.2 shall be verified by a reference receiver diode with tr ≤ 0,2 às.
Optical characteristics
The wavelength of the radiated signals for emitting systems is between 550 nm and 1 000 nm
The output device in the meter must produce a signal with a radiation strength \( E_T \) over a specified reference surface (optically active area) at a distance of \( a_1 = 10 \, \text{mm} \pm 1 \, \text{mm} \) from the meter's surface, adhering to defined limiting values.
ON-condition: 50 àW/cm² ≤ E T ≤ 1 000 àW/cm²
NOTE Where a meter uses a modulated output the ON condition value refers to the measurement when the output device is
ON and not the average level over the modulated period.
Marking of meter
Name-plates
Every meter must display essential information, including the manufacturer's name or trademark and, if necessary, the place of manufacture It should indicate the type designation and provide space for approval marks, such as the European Community (EC) type examination certificate number Additionally, the meter must feature the conformity marking as mandated by European Directives, along with details on the number of phases and wires it supports (e.g., single-phase 2-wire, three-phase 3-wire, three-phase 4-wire), which can be represented by graphical symbols from EN 62053-52 Furthermore, the meter should include a serial number and year of manufacture, with the serial number also marked on the meter base or stored in its non-volatile memory if located on a cover plate Lastly, the reference voltage must be specified in an appropriate format.
– the number of elements if more than one, and the voltage at the meter terminals of the voltage circuit(s);
– the rated voltage of the system or the secondary voltage of the instrument transformer to which the meter is intended to be connected
Examples of markings are shown in Table 6
Meter Voltage at the terminals of the voltage circuit (s) Rated system voltage
Three-phase 4 wire 3 element meter for more than one reference voltage
– for direct connected meters, the minimum current (I min ), reference current (I ref ), and maximum current (I max), for example, 0,5-10(80) A;
NOTE Marking the reference current is necessary to avoid confusion with marking of meters according to EN 62052-11
Transformer-operated meters require specific parameters for proper operation, including the minimum current (I min) and the rated secondary current, such as 0.05 - /5A, or the minimum (I min), rated (I n), and maximum current (I max), for example, 0.01-1(6)A Additionally, it is essential to note the reference frequency in Hz, the meter constant, and the class index of the meter The specified operating temperature range, or environmental class according to 6.1, should also be indicated, for instance, –25 °C to 55 °C or 3K6 For insulating encased meters of protective class II, the double square sign (IEC 60417-5172: Class II equipment) must be displayed.
The meter cover may feature permanent markings for information categorized under a) to d), while details from e) to l) should ideally be displayed on a name-plate inside the meter All markings must be indelible, non-transferable, distinct, and easily legible from outside the meter.
For special types of meters, such as multi-rate meters, any differences in the voltage of the change-over device from the reference voltage must be clearly indicated on the nameplate or on a separate plate.
If the instrument transformers are taken into account in the meter constant, the transformer ratio(s) shall be marked
When instrument transformers are included in the meter constant, the transformer ratios may be indicated on the meter itself or made available for the consumer on the display.
Standard symbols may also be used (see EN 62053-52).
Connection diagrams and terminal marking
Every meter should ideally feature a permanent connection diagram If this is not feasible, a reference to a connection diagram must be provided For polyphase meters, the diagram must also indicate the intended phase sequence Additionally, the connection diagram may be presented according to the specifications of the purchaser.
If the meter terminals are marked, this marking shall appear on the diagram.
Accompanying information
For each meter type, an instruction manual shall be made available and it shall include information on the following:
– mechanical and electromagnetic environment the meter is intended for;
– the upper and lower temperature limit, whether the meter is designed for condensing or non- condensing humidity as well as the intended location for the meter, i.e indoor or outdoor;
– instructions for installation, including any limitations to ensure that the essential requirement of reproducibility is met, maintenance, repairs, permissible adjustments, if any;
– instructions for correct operation and any special conditions of use;
– description of any interfaces and conditions for compatibility with other devices or systems
Individual instruction manuals are not required
Temperature ranges
The manufacturer must define the upper and lower temperature limits for the specified operating range, as well as the limits for operation, storage, and transportation conditions, based on the values provided in Table 7.
Table 7 – Upper and lower temperature limits
Values of upper temperature limit 30 °C 40 °C 55 °C 70 °C
Values of lower temperature limit 5 °C -10 °C -25 °C -40 °C
The manufacturer must specify on the nameplate or in the instruction manual whether the meter is intended for condensing or non-condensing humidity, along with its designated location for use, such as indoor or outdoor settings.
The preferred pairs of upper and lower temperature limits are shown in Table 8
Table 8 – Preferred upper and lower temperature limits corresponding to IEC environmental classes
(EN 60721-3-2 Table 1) -25 °C to 70 °C (2K3) -40 °C to 70 °C (2K4) a Class 3K5 is -5 °C to 45 °C b For special applications, other temperature values can be used according to purchaser contract For example, for cold environment for indoor meters, class 3K7.
Relative humidity
The meter shall be designed to withstand the climatic conditions defined in Table 9 For combined temperature and humidity test, see 6.3.4
For 30 days, these days being spread in a natural manner over one year 95 %
The limits of relative humidity as a function of ambient temperature are shown in Annex A.
Tests of the effect of the climatic environments
General
After each of the climatic tests, the meter shall show no damage or change of the information and shall operate correctly.
Dry heat test (Test B)
The test shall be carried out according to EN 60068-2-2, under the following conditions:
– meter in non-operating condition;
– method Bb (with gradual change of temperature);
Cold test (Test A)
The test shall be carried out according to EN 60068-2-1, under the following conditions:
– meter in non-operating condition;
– method Ab (with gradual change of temperature);
– duration of the test: 72 h for indoor meters;
Damp heat cyclic test (Test Db)
The test shall be carried out according to EN 60068-2-30, under the following conditions:
– voltage and auxiliary circuits energized with reference voltage;
– without any current in the current circuits;
– upper temperature: +40 °C ± 2 °C for indoor meters;
– no special precautions shall be taken regarding the removal of surface moisture;
– duration of the test: 6 cycles
Twenty-four hours after completing the test, the meter must undergo the following evaluations: a) an insulation test as per section 7.3, with the impulse voltage reduced by a factor of 0.8; b) a functional test to ensure the meter displays no damage or information alteration and operates correctly.
The damp heat test functions as a corrosion assessment, with results evaluated visually It is essential that no signs of corrosion that could impact the meter's functional properties are observed.
Protection against solar radiation (Test Sa)
The meter for outdoor use shall withstand solar radiation
The test shall be carried out according to EN 60068-2-5, under the following conditions:
– meter in non-operating condition;
– test procedure A (8 h irradiation and 16 h darkness);
– duration of the test: 3 cycles or 3 days
After testing, a visual inspection of the meter is required to ensure that its appearance and the legibility of markings remain unchanged, and that its functionality is not compromised.
Voltage range
Specified operating range From 0,9 U n to 1,1 U n
Extended operating range From 0,8 U n to 1,15 U n
Limit range of operation From 0,0 U n to 1,15 U n
NOTE For maximum voltages under earth fault conditions see the relevant standards for particular requirements.
Heating
Under rated operating conditions, electrical circuits and insulation shall not reach a temperature, which might adversely affect the operation of the meter
The insulation materials shall comply with the appropriate requirements of EN 60085
Under conditions where each current circuit of the meter is at its rated maximum current and each voltage circuit, along with auxiliary voltage circuits energized beyond their thermal time constants, operates at 1.15 times the reference voltage, the external surface temperature must not exceed 25 K above an ambient temperature of 40 °C.
During the test, the duration of which shall be 2 h, the meter shall be exposed neither to draught nor to direct solar radiation
NOTE Consideration should be given to items such as cable size, cable type, mounting of the meter, length of the current path as these can affect the result.
After the test, the meter shall show no damage and shall comply with the dielectric strength tests of 7.3.
Insulation
Requirements
The meter and its auxiliary devices must maintain sufficient dielectric properties during regular use, considering the impact of environmental conditions and varying voltages encountered in typical operating scenarios.
The meter shall withstand the impulse voltage test and the a.c voltage test as specified in 7.3.2 to 7.3.4.
General test conditions
Tests will only be conducted on a complete meter, including its cover and terminal cover, unless specified otherwise The terminal screws must be tightened to accommodate the maximum applicable conductor fitted in the terminals.
Test procedure in accordance with HD 588.1 S1
The impulse voltage tests shall be carried out first and the a.c voltage tests afterwards
Dielectric strength tests are deemed valid solely for the specific terminal arrangement of the meter that was tested If the terminal arrangements vary, it is necessary to conduct dielectric strength tests for each configuration.
In these tests, "earth" is defined as follows: a) if the meter case is metal, the "earth" refers to the case itself, positioned on a flat conducting surface; b) if the meter case or part of it is insulating, the "earth" is a conductive foil that wraps around the meter, touching all accessible conductive parts and connected to the flat conducting surface beneath the meter base Additionally, when the terminal cover allows, the conductive foil must be within 2 cm of the terminals and conductor holes.
During the impulse and the a.c voltage tests, the circuits which are not under test are connected to the earth as indicated hereafter
Following the tests, the percentage error of the meter under reference conditions should not exceed the measurement's repeatability, and there should be no mechanical damage to the equipment.
In this subclause, the expression "all the terminals" means the whole set of terminals of the current circuits, voltage circuits and, if any, auxiliary circuits having a reference voltage over 40 V
These tests shall be made in normal conditions of use During the test, the quality of the insulation shall not be impaired by dust or abnormal humidity
Unless otherwise specified, the normal conditions for insulation tests are:
– atmospheric pressure: 86 kPa to 106 kPa
If for any reason the insulation tests have to be repeated, then they may be performed on a new specimen.
Impulse voltage test
The test shall be carried out under the following conditions:
– impulse waveform: 1,2/50 impulse as specified in HD 588.1 S1;
– test voltage: in accordance with Table 4 or Table 5 as appropriate;
For each test, the impulse voltage is applied ten times with one polarity and then repeated with the other polarity The minimum time between the impulses shall be 3 s
NOTE For areas where overhead supply networks are predominant, higher values than given in Table 4 and Table 5 may be required
7.3.3.2 Impulse voltage tests for circuits and between the circuits
Each circuit or assembly of circuits must be tested independently, ensuring they are insulated from other circuits in normal operation The terminals of circuits not exposed to impulse voltage should be grounded.
In normal operation, the voltage and current circuits of a measuring element must be connected for testing The voltage circuit's other end should be grounded, while the impulse voltage is applied between the current circuit terminal and the ground If multiple voltage circuits share a common point, this point must also be grounded, and the impulse voltage should be applied sequentially between each free end of the connections (or the connected current circuit) and the ground, with the other terminal of the current circuit left open.
In normal usage, when the voltage and current circuits of the same measuring element are properly insulated and separated—such as when each circuit is connected to a measuring transformer—tests should be conducted individually on each circuit.
When testing a current circuit, ensure that the terminals of other circuits are grounded, and apply the impulse voltage between one terminal of the current circuit and the ground For voltage circuit testing, connect the terminals of other circuits and one terminal of the voltage circuit to the ground, then apply the impulse voltage between the remaining terminal of the voltage circuit and the ground.
Auxiliary circuits that connect directly to the mains or to transformers with the same voltage as the meter circuits, and have a reference voltage exceeding 40 V, must undergo impulse voltage testing under the same conditions as voltage circuits However, other auxiliary circuits are exempt from testing.
7.3.3.3 Impulse voltage test of electric circuits relative to earth
All the terminals of the electric circuits of the meter, including those of the auxiliary circuits with a reference voltage over 40 V, shall be connected together
The auxiliary circuits with a reference voltage below or equal to 40 V shall be connected to earth The impulse voltage shall be applied between all the electric circuits and earth
During this test no flashover, disruptive discharge or puncture shall occur.
AC voltage test
See relevant standard for particular requirements.
Electromagnetic compatibility (EMC)
Electromagnetic environment
Considering the electromagnetic environment of electricity metering equipment, the following phenomena are relevant:
– voltage dips and short interruptions;
– conducted disturbances, induced by RF fields;
– power frequency magnetic fields of external origin;
– continuous magnetic fields of external origin;
For requirements and testing, see 7.4.2 to 7.4.13
Some of the tests are not applicable to electromechanical meters – see EN 61000-4-1 – these cases are indicated.
General requirements and test conditions
Meters shall be designed in such a way that conducted or radiated electromagnetic phenomena and electrostatic discharge neither damage nor substantially influence the result of measurement
Electromagnetic disturbances of long duration shall not cause an additional percentage error more than the critical change values specified in the relevant particular requirements standards
The effect of transient electromagnetic disturbances shall be such that:
– during and immediately after a disturbance the test output shall not produce a signal equivalent of more than x; and in a reasonable time after the disturbance the meter shall:
– recover to operate within the error limits specified in the relevant standards;
– have all measurement functions safeguarded;
– allow recovery of all measurement data present prior to the disturbance;
– not indicate a change in the register more than x; where x is the critical change value specified in 7.4.3
For all tests, the meter must be positioned in its standard working state, with both the cover and terminal covers securely in place Additionally, all components designated for earthing must be properly earthed.
Critical change value
For evaluating the effect of transient electromagnetic disturbances, the critical change value is derived from the following formula: max
10 6 m U I x = − ⋅ ⋅ n ⋅ where x is the critical change value in kWh units; m is the number of measuring elements;
U n is the reference voltage in volts;
I max is the maximum current in amperes.
Immunity to voltage dips and short interruptions
Voltage dips and short interruptions must not cause a change in the register exceeding x units, and the test output should not generate a signal greater than x units for each specified test.
When the voltage is restored, the meter shall not have suffered degradation of its metrological characteristics
The tests shall be carried out according to EN 61000-4-11, under the following conditions:
– voltage and auxiliary circuits energized with reference voltage ± 5 %;
– without any current in the current circuits a) voltage interruptions of ∆U = 100 %
– restoring time between interruptions: 50 ms See also Figure C.1 b) voltage interruptions of ∆U = 100 %
– interruption time: one cycle at reference frequency;
– number of interruptions: 1 See also Figure C.2 c) voltage dips of ∆U = 50 %
– number of dips: 1 See also Figure C.3.
Immunity to electrostatic discharges
This test is not applicable to electromechanical meters
The test shall be carried out according to EN 61000-4-2, under the following conditions:
– tested as table-top equipment;
– voltage and auxiliary circuits energized with reference voltage ± 5 %;
– without any current in the current circuits (open circuit);
– number of discharges: 10 (in the most sensitive polarity)
If contact discharge is not applicable because no metallic parts are outside, then apply air discharge with a 15 kV test voltage
NOTE For meters of Protective Class II air discharge is most likely to be applicable
The use of electrostatic discharges must not result in a change exceeding x units, and the test output should not generate a signal greater than x units.
During the test, a temporary degradation or loss of function or performance is acceptable.
Immunity to radiated RF electromagnetic fields
This test is not applicable to electromechanical meters
The test shall be carried out according to EN 61000-4-3, under the following conditions:
– tested as table-top equipment;
– cable length, exposed to the field: 1 m;
– frequency band: 80 MHz to 2 000 MHz;
– carrier modulated with 80 % AM at 1 kHz sine wave
For example of test set-up see Figure D.1 a) Test with current:
– voltage and auxiliary circuits energized with reference voltage;
– current and power factor as specified in the relevant standard;
During testing, it is essential that the equipment's behavior remains stable, ensuring that the additional percentage error does not surpass the critical change values outlined in the applicable standards Additionally, tests should be conducted without any current.
– voltage and auxiliary circuits energized with reference voltage + 5 %;
– without any current in the current circuits and the current terminals shall be open circuit; – unmodulated test field strength: 30 V/m
The RF field application must not result in a change exceeding x units, and the test output should not generate a signal greater than x units.
During the test, a temporary degradation or loss of function or performance is acceptable.
Immunity to electrical fast transients/bursts
The test shall be carried out according to EN 61000-4-4, under the following conditions:
– tested as table-top equipment;
– voltage and auxiliary circuits energized with reference voltage;
– current and power factor as specified in the relevant standard;
– cable length between coupling device and EUT: 1 m;
– the test voltage shall be applied in common mode (line to earth) in turn to:
– the current circuits, if separated from the voltage circuits in normal operation;
– the auxiliary circuits, if separated from the voltage circuits in normal operation;
– test voltage on the current and voltage circuits: 4 kV;
– test voltage on the auxiliary circuits with a reference voltage over 40 V: 2 kV;
– duration of the test: 60 s at each polarity
During testing, a temporary decline in function or performance is permissible, provided that the additional percentage error does not surpass the critical change values outlined in the applicable standards.
NOTE The accuracy may be determined by registration method or other suitable means
For examples of test set-up see Figure D.2 and Figure D.3.
Immunity to conducted disturbances, induced by RF fields
The test shall be carried out according to IEC 61000-4-6, under the following conditions:
– tested as table-top equipment;
– voltage and auxiliary circuits energized with reference voltage;
– current and power factor as specified in the relevant standard;
– frequency range: 150 kHz to 80 MHz;
During the test the behaviour of the equipment shall not be perturbed and the additional percentage error shall not exceed the critical change values specified in the relevant standards.
Immunity to surges
The test shall be carried out according to EN 61000-4-5, under the following conditions:
– voltage and auxiliary circuits energised with reference voltage + 5 %;
– without any current in the current circuits and the current terminals shall be open circuit; – cable length between surge generator and meter: 1 m;
– tested in differential mode (line to line);
– phase angle: pulses to be applied at 60° and 240° relative to zero crossing of a.c supply;
– test voltage on the current and voltage circuits (mains lines): 4 kV, generator source impedance: 2 Ω;
– test voltage on auxiliary circuits with a reference voltage over 40 V: 1 kV, generator source impedance: 42 Ω;
– number of pulses: 5 positive and 5 negative;
The surge immunity test voltage must not cause a change in the register exceeding x units, and the test output should not generate a signal greater than x units.
During the test, a temporary degradation or loss of function or performance is acceptable.
Immunity to damped oscillatory waves
The test shall be carried out according to EN 61000-4-12, under the following conditions:
– only for voltage transformer operated meters, intended for use in power plants and high-voltage substations;
– tested as table-top equipment;
– voltage and auxiliary circuits energised with reference voltage;
– current and power factor as specified in the relevant standard;
– test voltage on voltage circuits and auxiliary circuits with a reference voltage > 40 V:
– test duration: 60 s (15 cycles with 2 s on, 2 s off, for each frequency)
During the test the behaviour of the equipment shall not be perturbed and the additional percentage error shall not exceed the critical change values specified in the relevant standards.
Immunity to continuous magnetic fields of external origin
The test shall be performed using the electromagnet according to Annex E, energized with d.c current
– voltage and auxiliary circuits energised with reference voltage;
– current and power factor as specified in the relevant standard;
– the value of the magneto-motive force shall be 1 000 At (ampere-turns);
– the magnetic field shall be applied to all accessible surfaces of the meter when it is mounted as for normal use
During the test the behaviour of the equipment shall not be perturbed and the additional percentage error shall not exceed the critical change values specified in the relevant standards.
Immunity to power frequency magnetic fields of external origin
The test shall be carried out according to EN 61000-4-8, under the following conditions:
– tested as table-top equipment;
– induction coil as per Subclause 6.2.1.a) of EN 61000-4-8;
– the current flowing through the coil shall be applied in the most unfavourable conditions of phase and direction compared to the voltage(s) energising the meter;
– frequency equal to reference frequency;
– magnetic field applied in three perpendicular planes;
– voltage and auxiliary circuits energised with reference voltage;
– current and power factor as specified in the relevant standard;
– test with continuous field, field strength 0,5 mT;
During the test the behaviour of the equipment shall not be perturbed and the additional percentage error shall not exceed the critical change values specified in the relevant standards.
Radio interference suppression
The test shall be carried out according to EN 55022, under the following conditions:
– tested as table-top equipment;
– for connection to the voltage circuits, an unshielded cable length of 1 m to each connector shall be used;
– voltage and auxiliary circuits energised with reference voltage;
– with a current between 0,1 I ref and 0, 2 I ref (drawn by linear load and connected by unshielded cable length of 1 m).
The test results shall comply with the requirements given in EN 55022
Test conditions
All tests are carried out under reference conditions unless otherwise stated in the relevant clause
The type test outlined in section 3.7 must be conducted on one or more meter specimens chosen by the manufacturer to verify their specific characteristics and ensure compliance with the standard's requirements.
A recommended test sequence is given in Annex F
Modifications to the meter made after the type test, which only impact certain parts of the meter, require only limited testing on the characteristics potentially affected by these changes.
Relationship between ambient air temperature and relative humidity
- - - Limits for each of 30 days spread in a natural manner over one year
_ _ _ _ _ _ _ _ Limits occasionally reached on other days
Figure A.1 – Relationship between ambient air temperature and relative humidity
Optical axis of the transmitter
Reference surface (optically active area approx 0,5 cm 2 , ỉ 8 mm ± 1 mm)
Figure B.1 – Test arrangement for the test output
Requirements: t ON ≥ 0,2 ms ; t OFF ≥ 0,2 ms ; t T < 20 às
Figure B.2 – Waveform of the optical test output
Voltage waveform for the tests of the effect of voltage dips and short interruptions t
Figure C.2 – Voltage interruptions of ∆U = 100 %, one cycle at rated frequency t
Test set-up for electromagnetic compatibility (EMC) tests
NOTE To obtain the test field strength of 30 V/m it is possible to reduce the distance between antenna and EUT down to 1,5 m
In this case, the adjustment of the amplifier must be controlled by a field sensor
Figure D.1 – Test set-up for immunity to radiated RF electromagnetic fields
V ol tage sourc e Current sourc e
Coupl in g dev ic e Net w ork filte rin g
3) Auxiliary circuits with a reference voltage over 40 V
4) Auxiliary circuits with a reference voltage below 40 V
Figure D.2 – Test set-up for immunity to electrical fast transients/bursts: voltage circuits
V ol tage sourc e Current sourc e
3) Auxiliary circuits with a reference voltage over 40 V
4) Auxiliary circuits with a reference voltage below 40 V
Figure D.3 – Test set-up for immunity to electrical fast transients/bursts: current circuits
Electromagnet for testing the influence of continuous magnetic fields of external origin
Figure E.1 – Electromagnet for testing the influence of continuous magnetic fields of external origin
Test schedule - Recommended test sequences
3 Tests of effect of disturbances of long duration
3.7 Accuracy in the presence of harmonics X 8.7.7.7 8.7.7.7
3.8 Odd harmonics and sub-harmonics X N.A 8.7.7.9
3.11 Mechanical load of the register X 8.7.7.11 N.A
5 Tests for electromagnetic compatibility (EMC)
5.1 Immunity to voltage dips and short interruptions 7.4.4 X X
5.3 Immunity to electrical fast transients/bursts 7.4.7 8.7.7.13 8.7.7.14 5.4 Immunity to damped oscillatory waves 7.4.10 8.7.7.15 8.7.7.16
5.5 Immunity to radiated RF electromagnetic fields 7.4.6 N.A 8.7.7.12
5.6 Immunity to conducted disturbances, induced by RF fields
5.9 Immunity to power frequency magnetic fields of external origin
5.10 Immunity to continuous magnetic induction of external origin 7.4.11 8.7.7.8 8.7.7.10
6 Tests of the effect of the climatic environments
6.3 Damp heat, cyclic test (Test Db) 6.3.4 X X
6.4 Solar radiation test (Test Sa) 6.3.5 X X
7.3 Spring hammer test (Test Eh) 5.2.2.1 X X
7.4 Protection against penetration of dust and water 5.9 X X
7.5 Resistance to heat and fire 5.8 X X
NOTE 1 X - The relevant test is defined in another part of the standard
NOTE 2 N.A - The test is not relevant for the type of the meter, which is subject to the standard
Coverage of Essential Requirements of EC Directives
This European Standard, developed under a mandate from the European Commission and the European Free Trade Association, addresses the essential requirements outlined in Article 4(a) of the EC Directive 89/336/EEC.
– all relevant essential requirements as given in Annex I and Annex MI-003 of the EC Directive 2004/22/EC
Compliance with this standard provides one means of conformity with the specified essential requirements of the Directives concerned
WARNING: Other requirements and other EC Directives may be applicable to the products falling within the scope of this standard
The article discusses various electrical testing parameters, including a \$1.2/50\$ impulse and a \$35\$ a.c voltage test, which are essential for assessing the performance of active energy meters It highlights the significance of accessible conductive parts and accompanying information for safety compliance The text also covers the concepts of active power, apparent power, and the additional percentage error that may arise during measurements Ambient temperature and atmospheric pressure are noted as critical factors influencing test results, along with the importance of basic insulation and clearance distances Furthermore, the article addresses the role of auxiliary devices and circuits in enhancing system functionality, while also considering climatic conditions and the impact of conducted disturbances induced by RF fields on device performance.
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The article discusses various aspects of electrical safety and testing, including the importance of dielectric strength tests and the design examination certificate It highlights the significance of current ranges and the impact of electrical fast transients on equipment Additionally, it addresses the role of damped oscillatory waves and electromagnetic compatibility in ensuring reliable performance The use of direct connected meters and electromechanical registers is also mentioned, along with the necessity for double insulation to protect against disturbances such as electrostatic discharges Finally, the article emphasizes the need for proper display of measured values to enhance user understanding and safety.
EMC tests are crucial for ensuring the reliability of devices in various environments, particularly for indoor meters that operate within extended ranges These tests assess immunity to fast transients and bursts, as well as the effects of impulse voltage Proper installation conditions and adherence to instruction manuals are essential for maintaining the functionality of instruments, including induction coils and instrument transformers Understanding the influence quantities and harmonic components is vital for accurate measurements, while insulating barriers and insulation tests help mitigate risks associated with hazardous live parts Additionally, recognizing the fundamental components and their graphical symbols aids in the effective design and implementation of electrical systems, ensuring minimal intrinsic error during operation.
The article discusses various technical specifications and operational parameters of meters, including their protective classes, metrological properties, and measuring ranges Key features such as the IP54 rating, 27 kilowatt-hour capacity, and maximum permissible error are highlighted, along with the importance of non-volatile memory and meter constants It also addresses the significance of reference conditions, including temperature and voltage, and the role of mechanical elements in ensuring accurate measurements The document emphasizes the need for compliance with standards, such as type examination certificates and test outputs, to ensure reliability and accuracy in different operational environments Additionally, it covers aspects like pulse output devices, rated currents, and the effects of external factors like radio interference and temperature variations on meter performance.
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