EN 50470-2:2006

SLOVENSKI STANDARD
01-marec-2007
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Electricity metering equipment (a.c.) -- Part 2: Particular requirements -
Electromechanical meters for active energy (class indexes A and B)
Wechselstrom-Elektrizitätszähler -- Teil 2: Besondere Anforderungen -
Elektromechanische Wirkverbrauchszähler der Genauigkeitsklassen A und B
Equipement de comptage d'électricité (c.a.) -- Partie 2: Prescriptions particulières -
Compteurs électromécaniques d'énergie active (classes de précision A et B)
Ta slovenski standard je istoveten z: EN 50470-2:2006
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 50470-2
NORME EUROPÉENNE
October 2006
EUROPÄISCHE NORM
ICS 91.140.50
English version
Electricity metering equipment (a.c.)
Part 2: Particular requirements -
Electromechanical meters for active energy
(class indexes A and B)
Equipement de comptage  Wechselstrom-Elektrizitätszähler
d'électricité (c.a.) Teil 2: Besondere Anforderungen -
Partie 2: Prescriptions particulières - Elektromechanische
Compteurs électromécaniques Wirkverbrauchszähler
d'énergie active der Genauigkeitsklassen A und B
(classes de précision A et B)
This European Standard was approved by CENELEC on 2006-05-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50470-2:2006 E
Foreword
This European Standard was prepared by the Technical Committee CENELEC TC 13, Equipment for
electrical energy measurement and load control.
The text of the draft was submitted to the Unique Acceptance Procedure and was approved by
CENELEC as EN 50470-2 on 2006-05-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2007-05-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2009-05-01
This EN 50470-2 is related to EN 62053-11:2003, Electricity metering equipment (a.c.) – Particular
requirements – Part 11: Electromechanical meters for active energy (classes 0,5, 1 and 2).
The structure of the two standards is similar, modifications in this European Standard are provided in
the perspective of compliance with the Essential Requirements of the Directive 2004/22/EC on
Measuring Instruments (MID).
This standard is to be used with EN 50470-1:2006, Electricity metering equipment (a.c.) – Part 1:
General requirements, tests and test conditions – Metering equipment (class indexes A, B and C).
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and covers essential requirements of
EC Directive 2004/22/EC. See Annex ZZ.
__________
– 3 – EN 50470-2:2006
Contents
1 Scope.5
2 Normative references .5
3 Terms, definitions and abbreviations .5
4 Standard electrical values .6
5 Mechanical requirements.6
5.1 General .6
5.2 Register (counting mechanism) .6
5.3 Direction of rotation and marking of the rotor.6
6 Climatic conditions .6
7 Electrical requirements .6
7.1 Power consumption .6
7.1.1 Measuring method .6
7.1.2 Voltage circuits.7
7.1.3 Current circuits .7
7.2 AC voltage test.7
8 Accuracy requirements and tests.9
8.1 Limits of percentage error due to variation of the load .9
8.2 Repeatability .9
8.3 Limits of additional percentage error due to influence quantities.9
8.4 Maximum permissible error (MPE).11
8.5 Effect of disturbances of long duration.11
8.6 Short time overcurrents .13
8.7 Performing the tests .13
8.7.1 Accuracy test conditions.13
8.7.2 Accuracy test at reference conditions .15
8.7.3 Interpretation of accuracy test results .15
8.7.4 Repeatability .15
8.7.5 Test of effects of influence quantities.15
8.7.6 Calculation of the composite error .16
8.7.7 Test of effects of disturbances of long duration.16
8.7.8 Short time overcurrents .19
8.7.9 Test of starting and no-load condition .19
8.7.10 Meter constant.20
8.7.11 Adjustment .20
9 Durability.21
10 Reliability .21
11 Protection against corruption .21
Annex A (informative) Calculation of the composite error .22
Annex B (normative) Test circuit diagram for the test of immunity to earth fault .23
Annex ZZ (informative) Coverage of Essential Requirements of EC Directives.24
Bibliography.25

Figures
Figure B.1 – Circuit to simulate earth fault condition in phase 1 .23
Figure B.2 – Voltages at the meter under test .23
Tables
Table 1 – Power consumption in voltage circuits .7
Table 2 – Power consumption in current circuits .7
Table 3 – AC voltage tests.8
Table 4 – Percentage error limits at reference conditions (single-phase meters and
polyphase meters with balanced loads) .9
Table 5 – Percentage error limits at reference conditions (polyphase meters carrying a
single-phase load, but with balanced polyphase voltages applied to voltage
circuits) .9
Table 6 – Limits of additional percentage error due to influence quantities (single-
phase meters and polyphase meters with balanced loads).10
Table 7 – Limits of additional percentage error due to influence quantities (polyphase
meters carrying a single phase load, but with balanced polyphase voltages
applied to voltage circuits).10
Table 8 – Maximum permissible error (MPE).11
Table 9 – Effect of disturbances of long duration – Critical change values .12
Table 10 – Effect of short time overcurrents – Critical change value .13
Table 11 – Voltage and current balance.13
Table 12 – Reference conditions.14
Table 13 – Test points for determining the intrinsic error and the additional percentage
error due to influence quantities .15
Table 14 – Interpretation of test results.15
Table 15 – Starting current .20
Table 16 – Minimum range of adjustment.20

__________
– 5 – EN 50470-2:2006
1 Scope
This European Standard applies to newly manufactured electromechanical watt-hour meters intended
for residential, commercial and light industrial use, of class indexes A and B, for the measurement of
alternating current electrical active energy in 50 Hz networks. It specifies particular requirements and
type test methods.
It applies to electromechanical watt-hour meters for indoor and outdoor application, consisting of a
measuring element and register(s) enclosed together in a meter case. It also applies to operation
indicator(s) and test output(s).
If the meter has (a) measuring element(s) for more than one type of energy (multi-energy meters), or
when other functional elements, like maximum demand indicators, electronic tariff registers, time
switches, ripple control receivers, data communication interfaces etc. are enclosed in the meter case
(multi-function meters) then this standard applies only for the active energy metering part.
This standard distinguishes between:
– meters of class indexes A and B;
– direct connected and transformer operated meters;
– meters for use in networks equipped with or without earth fault neutralizers.
It does not apply to:
– watt-hour meters where the voltage across the connection terminals exceeds 600 V (line-to-line
voltage for meters for polyphase systems);
– portable meters.
1)
Methods for acceptance testing are covered by the IEC 62058 series of standards .
The dependability aspect is covered by the documents of the IEC 62059 series.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
Publication Year Title
EN 50470-1 2006 Electricity metering equipment (a.c.) – Part 1: General requirements, tests
and test conditions – Metering equipment (class indexes A, B and C)
3 Terms, definitions and abbreviations
For the purposes of this document, the terms and definitions given in EN 50470-1 apply.
———————
1)
At draft stage.
4 Standard electrical values
The values given in EN 50470-1 apply.
5 Mechanical requirements
In addition to the mechanical requirements in EN 50470-1, electromechanical meters shall fulfil the
following requirements.
5.1 General
The case of an electromechanical watt-hour meter shall be so constructed that, if mounted according
to the manufacturer’s instructions, the meter shall not deviate by more than 0,5° in all directions from
its vertical position (see also Footnote c of Table 12).
5.2 Register (counting mechanism)
The register may be of the drum or the pointer type.
In drum-type registers, the principal unit in which the register records shall be marked adjacent to the
set of drums.
In this type of register, only the last drum, i.e. the drum on the extreme right, may be continuously
movable.
In pointer-type registers, the unit in which the register records shall be marked adjacent to the units
dial in the form: 1 kWh/div, or 1 MWh/div, and the decimal multiples may be marked adjacent to the
other dials. For example, in a meter registering in terms of kilowatt-hours, the units dial shall be
marked: 1 kWh/div and, adjacent to the other dials to the left of the units dial, shall be marked:
10 - 100 - 1 000, etc.
5.3 Direction of rotation and marking of the rotor
The edge of the rotor nearest to an observer viewing a meter from the front shall move from left to
right for positive registration. The direction of rotation shall be marked by a clearly visible arrow.
The edge and/or upper surface of the disk shall carry an easily visible mark to facilitate revolution
counting. Other marks may be added for stroboscopic or other tests, but such marks shall be so
placed as not to interfere with the use of the main visible mark for photoelectric revolution counting.
6 Climatic conditions
The conditions given in EN 50470-1 apply.
7 Electrical requirements
In addition to the electrical requirements in EN 50470-1, meters shall fulfil the following requirements.
7.1 Power consumption
7.1.1 Measuring method
The power consumption in the voltage and current circuits shall be determined at reference conditions
given in 8.7.1 by any suitable method. The overall maximum error of the measurement of the power
consumption shall not exceed 5 %.

– 7 – EN 50470-2:2006
7.1.2 Voltage circuits
The active and apparent power loss in each voltage circuit of a meter at reference voltage, reference
temperature and reference frequency shall not exceed the values shown in Table 1.
Table 1 – Power consumption in voltage circuits
Class index
Meters
(single- and polyphase)
A B
Power consumption in voltage circuit 2 W and 10 VA 3 W and 12 VA
NOTE In order to match voltage transformers to meters, the meter manufacturer should state the
power factor of the burden (for transformer operated meters only).

7.1.3 Current circuits
The apparent power taken by each current circuit of a meter at reference current, reference frequency
and reference temperature shall not exceed the values shown in Table 2.
Table 2 – Power consumption in current circuits
Class index
Meters,
Test current
(single- and polyphase)
A B
Direct connected I < 30 A I = 10 I 2,5 VA 4,0 VA
ref ref tr
Direct connected I ≥ 30 A I = 10 I 4,0 VA 6,0 VA
ref ref tr
Transformer operated I 2,5 VA 4,0 VA
n
NOTE In order to match current transformers to meters, the meter manufacturer should state the
power factor of the burden (for transformer operated meters only).

7.2 AC voltage test
The a.c. voltage test shall be carried out in accordance with Table 3.
The test voltage shall be substantially sinusoidal, having a frequency between 45 Hz and 65 Hz, and
applied for 1 min. The power source shall be capable of supplying at least 500 VA.
For the tests relative to earth, the auxiliary circuits with reference voltage equal to or below 40 V shall
be connected to earth.
During this test no flashover, disruptive discharge or puncture shall occur.

Table 3 – AC voltage tests
Test Test voltage r.m.s. Points of application of the test voltage
Tests which may be carried out with the cover and terminal cover removed:

– between, on the one hand, the frame and,
– on the other hand:
2 kV for tests a) each current circuit which, in normal service, is separated and suitably
a
in Items a), b), c), d) insulated from the other circuits ;

b) each voltage circuit, or set of voltage circuits having a common point
which, in normal service, is separated and suitably insulated from the
a
other circuits ;
A
and c) each auxiliary circuit or set of auxiliary circuits having a common point,
and whose reference voltage is over 40 V;
d) each assembly of current-voltage windings of one and the same driving
element which, in normal service, are connected together but separated
b
and suitably insulated from the other circuits ;
500 V for test in e) each auxiliary circuit whose reference voltage is equal to or below 40 V.
Item e)
600 V or twice the Tests which may be carried out with the terminal cover removed, but with the
voltage applied to the cover in place when it is made of metal:
voltage windings
between the current circuit and the voltage circuit of each driving element,
under reference
B
normally connected together, this connection being temporarily broken for the
conditions, when this
c
purpose of the test .
voltage is greater than
300 V (the higher
value).
Tests to be carried out with the case closed, the cover and terminal cover in
place:
C 2 kV
between, on the one hand, all the current and voltage circuits as well as the
auxiliary circuits whose reference voltage is over 40 V, connected together,
and, on the other hand, earth.
Additional tests for insulating encased meters of protective class II:
4 kV for test in Item a) a) between on the one hand, all the current and voltage circuits as well as
the auxiliary circuits whose reference voltage is over 40 V, connected
together, and, on the other hand, earth;
D
b) between the frame and earth;
2 kV for test in Item b)
40 V for test in Item c) c) between, on the one hand, all conductive parts inside the meter case
connected together and, on the other hand, all conductive parts, outside
the meter case that are accessible with the test finger, connected
d
together .
a
The simple breaking of the connection, which is normally included between current and voltage windings is not generally
sufficient to ensure suitable insulation, which can withstand a test voltage of 2 kV.
Tests in part A) Items a) and b) generally apply to meters operated from instrument transformers and also to certain special
meters having separate current and voltage windings.
b
Circuits, which have been subjected to tests in part A) Items a) and b) are not subjected to the test in Item d). When the
voltage circuits of a polyphase meter have a common point in normal service, this common point shall be maintained for the
test and, in this case, all the circuits of the driving elements are subjected to a single test.
c
It is not, strictly speaking, a dielectric strength test, but a means of verifying that the insulation distances are sufficient when
the connecting device is open.
d
The test on part D item c) is not necessary, if the visual inspection for compliance with the conditions of EN50470-1
subclause 5.7 leaves no doubt.

– 9 – EN 50470-2:2006
8 Accuracy requirements and tests
8.1 Limits of percentage error due to variation of the load
When the meter is under reference conditions given in 8.7.1, and the current and the power factor are
varied, the percentage errors shall not exceed the limits specified for the relevant class indexes in
Table 4 and Table 5.
Table 4 – Percentage error limits at reference conditions
(single-phase meters and polyphase meters with balanced loads)
Value of current Percentage error limits
for direct connected or transformer for meters of class index
Power factor
operated meters
A B
I ≤ I < I 1 ± 2,5 ± 1,5
min tr
I ≤ I ≤ I 0,5 ind…1…cap 0,8 ± 2,0 ± 1,0
tr max
NOTE For the relationships I / I and I / I see EN 50470-1, Table 3.
min tr max tr
Table 5 – Percentage error limits at reference conditions
(polyphase meters carrying a single-phase load,
but with balanced polyphase voltages applied to voltage circuits)
Value of current Percentage error limits
for direct connected or transformer for meters of class index
Power factor
operated meters
A B
5 I ≤ I ≤ I 0,5 ind…1 ± 3,0 ± 2,0
tr max
NOTE For the relationship I / I see EN 50470-1, Table 3.
max tr
The difference between the percentage error when the meter is carrying a single-phase load and a
balanced polyphase load at I and unity power factor shall not exceed 2,5 % and 1,5 % for meters of
ref
class indexes A and B respectively.
8.2 Repeatability
The application of the same measurand under the same conditions of measurement shall result in the
close agreement of successive measurements. The repeatability at any test point given in Table 13
th
shall be better than 1/10 of the limit of percentage error at reference conditions. The manufacturer
shall state the necessary number of revolutions.
8.3 Limits of additional percentage error due to influence quantities
When the current and the power factor are held constant at a point within their respective specified
measuring ranges, and any single influence quantity is taken from its reference value and varied within
its specified operating range, with the meter otherwise operated at reference conditions as specified in
8.7.1, the additional percentage error shall not exceed the limits specified for the relevant class
indexes given in Table 6 and Table 7.
Concerning additional percentage error due to temperature variation, the requirements for each sub-
range within the full temperature range specified by the manufacturer apply.
NOTE For example, if the manufacturer specifies that the meter is intended for the temperature range -10 °C to +40 °C, then
the requirements for the sub-ranges 5 °C to 30 °C, -10 °C to 5 °C and 30 °C to 40 °C apply.

Table 6 – Limits of additional percentage error due to influence quantities
(single-phase meters and polyphase meters with balanced loads)
Value of current Limits of additional percentage error for
for direct meters of class index
Influence quantity Power factor
connected or
transformer
A B
operated meters
Temperature
variation
I ≤ I ≤ I
min max 1 ± 1,8 ± 0,9
5 °C to 30 °C
I ≤ I ≤ I 0,5 ind, 0,8 cap ± 2,7 ± 1,3
tr max
-10 °C to 5 °C I ≤ I ≤ I 1 ± 3,3 ± 1,6
min max
I ≤ I ≤ I 0,5 ind, 0,8 cap ± 4,9 ± 2,3
tr max
30 °C to 40 °C
-25 °C to -10 °C I ≤ I ≤ I 1 ± 4,8 ± 2,4
min max
I ≤ I ≤ I 0,5 ind, 0,8 cap ± 7,2 ± 3,4
tr max
40 °C to 55 °C
-40 °C to -25 °C I ≤ I ≤ I 1 ± 6,3 ± 3,1
min max
I ≤ I ≤ I 0,5 ind, 0,8 cap ± 9,4 ± 4,4
tr max
55 °C to 70 °C
I ≤ I ≤ I 1 ± 1,0 ± 0,7
min max
Voltage variation
± 10 %
I ≤ I ≤ I 0,5 ind, 0,8 cap ± 1,5 ± 1,0
tr max
Imin ≤ I ≤ Imax 1 ± 0,8 ± 0,5
Frequency variation
± 2 %
I ≤ I ≤ I 0,5 ind, 0,8 cap ± 1,0 ± 0,7
tr max
NOTE For the relationships I / I and I / I see EN 50470-1, Table 3.
min tr max tr
Table 7 – Limits of additional percentage error due to influence quantities
(polyphase meters carrying a single phase load,
but with balanced polyphase voltages applied to voltage circuits)
Value of current Limits of additional percentage error for
for direct meters of class index
Influence quantity connected or Power factor
transformer
A B
operated meters
Temperature
variation
1 ± 1,8 ± 0,9
5 °C to 30 °C 5 I ≤ I ≤ I
tr max
0,5 ind ± 2,7 ± 1,3
-10 °C to 5 °C 1 ± 3,3 ± 1,6
5 I ≤ I ≤ I
tr max
0,5 ind ± 4,9 ± 2,3
30 °C to 40 °C
-25 °C to -10 °C 1 ± 4,8 ± 2,4
5 I ≤ I ≤ I
tr max
0,5 ind ± 7,2 ± 3,4
40 °C to 55 °C
-40 °C to -25 °C 1 ± 6,3 ± 3,1
5 I ≤ I ≤ I
tr max
0,5 ind ± 9,4 ± 4,4
55 °C to 70 °C
1 ± 1,5 ± 1,0
Voltage variation
5 I ≤ I ≤ I
tr max
± 10 %
0,5 ind ± 2,0 ± 1,5
1 ± 1,0 ± 0,7
Frequency variation
5 I ≤ I ≤ I
tr max
± 2 %
0,5 ind ± 1,3 ± 1,0
NOTE For the relationship I / I see EN 50470-1, Table 3.
max tr
– 11 – EN 50470-2:2006
8.4 Maximum permissible error (MPE)
In addition to the requirements of 8.1 and 8.3, the composite error of the meter shall not exceed the
values given in Table 8.
When the operating range of the meter covers more than one temperature range, then the respective
requirements for each temperature range apply.
The composite error at a certain load shall be calculated from the following formula:
2 2 2 2
e = e (I, cosϕ) + δ (T ,I,cosϕ) + δ (U,I,cosϕ) + δ (f ,I,cosϕ)
c
where
e(I,cosϕ) = the intrinsic error of the meter at a certain load;
δ (T ,I,cosϕ) = the additional percentage error due to the variation of the temperature at
the same load;
δ (U,I,cosϕ) = the additional percentage error due to the variation of the voltage at the
same load;
δ (f ,I,cosϕ) = the additional percentage error due to the variation of the frequency at the
same load.
See also 8.7.6.
Table 8 – Maximum permissible error (MPE)
Operating temperature range
-10 °C to 5 °C or -25 °C to -10 °C or -40 °C to -25 °C or
5 °C to 30 °C
Value of Power
30 °C to 40 °C 40 °C to 55 °C 55 °C to 70 °C
current factor
Meter class index
A B A B A B A B
Single-phase meter; polyphase meter with balanced loads
I ≤ I < I 1 ± 3,5 ± 2,0 ± 5,0 ± 2,5 ± 7,0 ± 3,5 ± 9,0 ± 4,0
min tr
0,5 ind…1
I ≤ I ≤ I ± 3,5 ± 2,0 ± 4,5 ± 2,5 ± 7,0 ± 3,5 ± 9,0 ± 4,0
tr max
0,8 cap
Polyphase meter carrying a single-phase load, but with balanced voltage supplied to the voltage circuits
5 I ≤ I ≤ I 0,5 ind…1 ± 4,0 ± 2,5 ± 5,0 ± 3,0 ± 7,0 ± 4,0 ± 9,0 ± 4,5
tr max
8.5 Effect of disturbances of long duration
When the meter is otherwise operated at reference conditions, the additional percentage error due to
disturbances of long duration, when applied one by one, shall not exceed the critical change values
specified in Table 9.
For testing, see 8.7.7.
Table 9 – Effect of disturb
...