IEC 62020-1:2020

IEC 62020-1 ®
Edition 1.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical accessories – Residual current monitors (RCMs) –
Part 1: RCMs for household and similar uses

Petit appareillage électrique – Contrôleurs d'isolement à courant différentiel
résiduel (RCM) –
Partie 1: RCM pour usages domestiques et analogues

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IEC 62020-1 ®
Edition 1.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical accessories – Residual current monitors (RCMs) –

Part 1: RCMs for household and similar uses

Petit appareillage électrique – Contrôleurs d'isolement à courant différentiel

résiduel (RCM) –
Partie 1: RCM pour usages domestiques et analogues

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.50 ISBN 978-2-8322-8145-1

– 2 – IEC 62020-1:2020 © IEC 2020
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 12
3 Terms and definitions . 13
4 Classification . 15
4.1 According to the method of operation . 15
4.1.1 RCM functionally dependent on line voltage . 15
4.1.2 RCM functionally dependent on an energy source other than line
voltage . 15
4.2 According to the type of installation . 15
4.3 According to the number of current paths . 15
4.4 According to the ability to adjust the residual operating current . 15
4.5 According to the possibility of adjusting the time-delay . 15
4.6 According to the protection against external influences . 15
4.7 According to the method of mounting . 15
4.8 According to the method of connection . 15
4.9 According to the type of connection of the load conductors . 15
4.9.1 RCM to which the monitored line is not directly connected . 15
4.9.2 RCM to which the monitored line is directly connected. 16
4.10 According to fault indicating means . 16
4.11 According to ability to directionally discriminate between supply-side and
load-side residual currents . 16
4.12 According to the supply system . 16
4.12.1 RCM for use in AC supply systems . 16
4.12.2 RCM for use in DC supply systems . 16
4.13 According to the type of residual current monitored. 16
4.14 According to the method of residual current detection . 16
5 Characteristics of RCMs . 16
5.1 Summary of characteristics . 16
5.2 Rated quantities and other characteristics. 17
5.2.1 Rated voltage . 17
5.2.2 Rated current (I ) . 17
n
5.2.3 Rated residual operating current (I ) . 17
Δn
5.2.4 Rated residual non-operating current (I ) . 18
Δno
5.2.5 Rated frequency . 18
5.2.6 Operating characteristics . 18
5.3 Standard and preferred values . 18
5.3.1 Preferred values of rated voltage (U ) . 18
e
5.3.2 Preferred values of rated current (I ) . 19
n
5.3.3 Preferred values of rated residual operating current (I ) . 19
Δn
5.3.4 Standard value of residual non-operating current (I ) . 19
Δno
5.3.5 Standard minimum value of the non-operating overcurrent in the case of
single-phase load through an RCM . 19
5.3.6 Preferred values of rated frequency . 19
5.3.7 Standard and preferred values of the rated conditional short-circuit
current (I ) (only applicable to RCMs classified according to 4.9.2) . 19
nc
5.3.8 Maximum actuating time (T ) . 20
max
5.3.9 Minimum non-actuating time (T ) . 20
min
5.4 Coordination with short-circuit protective devices (SCPDs) (only valid for
RCMs classified according to 4.9.2) . 20
5.4.1 General . 20
5.4.2 Rated conditional short-circuit current (I ) . 20
nc
5.4.3 Rated conditional residual short-circuit current (I ) . 20
Δc
6 Marking and other product information . 20
7 Standard conditions for operation in service and for installation . 23
7.1 Standard conditions . 23
7.2 Conditions of installation . 24
8 Requirements for construction and operation . 24
8.1 Mechanical design . 24
8.1.1 General . 24
8.1.2 Features . 24
8.1.3 Clearances and creepage distances . 25
8.1.4 Screws, current-carrying parts and connections . 26
8.1.5 Terminals for external conductors . 27
8.2 Protection against electric shock . 29
8.3 Dielectric properties . 30
8.4 Temperature rise . 30
8.4.1 General . 30
8.4.2 Temperature rise limits . 30
8.4.3 Ambient air temperature . 31
8.5 Operating characteristic . 31
8.6 Directional discrimination . 31
8.7 Operational endurance . 31
8.8 Performance at short-circuit currents . 31
8.9 Resistance to mechanical impact . 31
8.10 Resistance to heat . 32
8.11 Resistance to abnormal heat and to fire . 32
8.12 Test device . 32
8.13 Correct operation of RCMs within the supply voltage range. 32
8.14 Behaviour of RCMs in case of overcurrents in the main circuit . 32
8.15 Resistance of RCMs to unwanted initiating of an alarm due to current surges

caused by impulse voltages . 33
8.16 Behaviour of RCMs in case of earth fault currents comprising DC
components . 33
8.17 Reliability . 33
8.18 Electromagnetic compatibility (EMC) . 33
8.18.1 General . 33
8.18.2 Immunity requirements . 33
8.18.3 Emission requirements . 33
8.19 Connection of an external current transformer (CT) . 33
8.20 Response to temporary overvoltages on the LV side due to fault conditions
on the HV side . 33
9 Tests . 34
9.1 General . 34
9.2 Test conditions . 35

– 4 – IEC 62020-1:2020 © IEC 2020
9.3 Test of indelibility of marking . 35
9.4 Test of reliability of screws, current-carrying parts and connections . 36
9.5 Test of reliability of terminals for external conductors . 37
9.6 Verification of protection against electric shock . 38
9.7 Test of dielectric properties . 39
9.7.1 Resistance to humidity. 39
9.7.2 Insulation resistance of the main circuits of RCMs classified according
to 4.9.2 . 39
9.7.3 Dielectric strength of the main circuit of RCMs classified according to
4.9.2 . 40
9.7.4 Insulation resistance and dielectric strength of control and auxiliary
circuits . 41
9.7.5 Secondary circuit of detection transformers . 42
9.7.6 Capability of the RCM to withstand high DC voltages due to insulation
measurements . 42
9.7.7 Verification of impulse withstand voltages . 42
9.8 Test of temperature rise . 44
9.8.1 Ambient air temperature . 44
9.8.2 Test procedure . 44
9.8.3 Measurement of the temperature rise of parts . 45
9.8.4 Temperature rise of a part . 45
9.9 Verification of the operating characteristics . 45
9.9.1 Test circuit . 45
9.9.2 Off-load tests with residual sinusoidal alternating currents at the
reference temperature of 20 °C ± 2 °C . 45
9.9.3 Verification of the correct operation with load at the reference
temperature . 46
9.9.4 Verification of the connection and the function of an external current
transformer (CT) . 46
9.9.5 Verification of directional discrimination for RCMs classified according
to 4.11 . 47
9.10 Verification of operational endurance . 48
9.10.1 General . 48
9.10.2 Test procedure . 48
9.11 Verification of short-circuit withstand capability . 48
9.11.1 List of the short-circuit tests . 48
9.11.2 Short-circuit tests . 48
9.12 Verification of resistance to mechanical impact . 53
9.12.1 General . 53
9.12.2 Test for all RCM types . 53
9.12.3 Rail-mounted RCMs . 55
9.12.4 Plug-in type RCMs . 55
9.13 Test of resistance to heat . 55
9.14 Test of resistance to abnormal heat and to fire . 56
9.15 Verification of the operation of the test device at the limits of rated voltage. 57
9.16 Verification of limiting values of the non-operating current under overcurrent
conditions . 57
9.16.1 General . 57
9.16.2 Verification of the limiting value of overcurrent in the case of a load
through an RCM with two current paths . 57

9.16.3 Verification of the limiting value of overcurrent in the case of a single-
phase load through a three-pole or four-pole RCM . 58
9.16.4 Verification of the limiting value of overcurrent in the case of a single-
phase load through an RCM with an external detecting device
(transformer) . 58
9.17 Verification of resistance against unwanted operation due to current surges
caused by impulse voltages . 59
9.18 Void . 59
9.19 Additional verification of the correct operation at residual currents with DC
components . 59
9.19.1 General . 59
9.19.2 Verification of the correct operation for RCM Type A, Type F and
Type B . 61
9.19.3 Verification of correct operation for RCM Type F and Type B . 62
9.19.4 Verification of correct operation for RCM Type B . 63
9.20 Verification of reliability . 66
9.20.1 General . 66
9.20.2 Climatic test . 66
9.20.3 Test with temperature of 40 °C . 68
9.21 Verification of ageing of electronic components . 68
9.22 Verification of EMC requirements . 68
9.22.1 General . 68
9.22.2 Description of quiescent mode and operate mode . 70
9.22.3 Criterion A1 . 70
9.22.4 Criterion A2 . 70
9.22.5 Criterion B . 70
9.23 Response of the RCM to temporary overvoltages on the LV side, due to fault
conditions on the HV side . 71
9.24 Test of resistance to rusting . 71
Annex A (normative) Test sequence and number of samples to be submitted for
verification of conformity to this document . 102
A.1 General . 102
A.2 Test sequences . 102
A.3 Number of samples to be submitted for full test procedure . 103
A.4 Number of samples to be submitted for simplified test procedures in case of
submitting simultaneously a range of RCMs of the same fundamental design . 103
Annex B (normative) Determination of clearances and creepage distances . 106
Bibliography . 109

Figure 1 – Standing current in FE conductor . 72
Figure 2 – Standard test finger (9.6) . 73
Figure 3 – Test circuit for verification of the operating characteristics for RCMs . 74
Figure 4 – Test circuit for verification of directional discrimination in IT systems for
RCMs classified according to 4.12 . 75
Figure 5 – Test circuit for verification of the correct operation of RCMs in the case of
residual pulsating direct currents . 76
Figure 6 – Test circuit for verification of the correct operation of RCMs in the case of
residual pulsating direct currents superimposed by smooth direct current of 0,006 A . 78
Figure 7 – Test circuit for verification of the coordination with an SCPD of an RCM with
two current paths (9.11) . 79

– 6 – IEC 62020-1:2020 © IEC 2020
Figure 8 – Test circuit for verification of the coordination with an SCPD of an RCM with
three current paths in a three-phase circuit (9.11) . 80
Figure 9 – Test circuit for verification of the coordination with an SCPD of an RCM with
four current paths on a three-phase circuit with neutral (9.11) . 81
Figure 10 – Test apparatus for verification of the minimum I t and I values to be
p
withstood by the RCM (9.11.2.1 a)) . 82
Figure 11 – Mechanical impact test apparatus (9.12.2) . 83
Figure 12 – Striking element for pendulum impact test apparatus (9.12.2) . 84
Figure 13 – Mounting support for sample for mechanical impact test (9.12.2) . 85
Figure 14 – Example of mounting an unenclosed RCM for mechanical impact test
(9.12.2) . 86
Figure 15 – Example of mounting of panel mounting type RCM for the mechanical
impact test (9.12.2) . 87
Figure 16 – Application of force for mechanical test of rail-mounted RCM (9.12.3) . 88
Figure 17 – Ball-pressure test apparatus (9.13.3) . 88
Figure 18 – Test circuit for verification of the limiting value of overcurrent in the case of
single-phase load . 89
Figure 19 – Current ring wave 0,5 µs/100 kHz . 90
Figure 20 – Test circuit for the ring-wave test of RCMs . 90
Figure 21 – Stabilizing period for reliability test (9.20.2.4) . 91
Figure 22 – Reliability test cycle (9.20.2.4) . 92
Figure 23 – Example test circuit for verification of ageing of electronic components
(9.21) . 93
Figure 24 – RCMs without monitored lines connected . 94
Figure 25 – RCMs with monitored lines connected . 94
Figure 26 – Example of a test circuit for verification of correct operation in case of
residual sinusoidal alternating currents composed of multi-frequency components
resulting from single-phase supplied speed motor control equipment . 95
Figure 27 – Test circuit for verification of correct operation in case of residual
sinusoidal alternating current up to 1 000 Hz . 96
Figure 28 – Test circuit for 2-,3- and 4-pole RCM Type B to verify the correct operation
in case of residual pulsating direct currents which may result from rectifying circuits
supplied from two phases . 97
Figure 29 – Test circuit for 3- and 4-pole RCM Type B to verify the correct operation in
case of residual pulsating direct currents which may result from rectifying circuits
supplied from three phases . 98
Figure 30 – Test circuit for 2-, 3- and 4-pole RCM Type B to verify the correct
operation in case of a residual smooth direct current . 99
Figure 31 – Diagrammatic representation for glow-wire test . 100
Figure 32 – Test circuit for 2-, 3- and 4-pole RCM Type B to verify the correct
operation in case of a residual alternating current superimposed on a smooth direct
current . 101
Figure B.1 – Illustrations of the application of creepage distances . 107
Figure B.2 – Illustrations of the application of creepage distances . 108

Table 1 – Marking . 21
Table 2 – Standard conditions for operation in service . 24
Table 3 – Clearances and creepage distances . 26

Table 4 – Connectable cross-sections of copper conductors for screw-type terminals . 28
Table 5 – Temperature rise values . 31
Table 6 – List of type tests depending on RCM classification . 34
Table 7 – Test copper conductors corresponding to the rated currents . 35
Table 8 – Screw thread diameters and applied torques . 36
Table 9 – Pulling forces . 37
Table 10 – Conductor dimensions . 38
Table 11 – Test voltage of control and auxiliary circuits . 41
Table 12 – Rated impulse withstand voltage as a function of the nominal voltage of the
installation . 44
Table 13 – Test voltage for verification of impulse withstand voltage . 44
Table 14 – Silver wire diameter as a function of rated current and short-circuit currents . 49
Table 15 – Minimum values of I t and I . 50
p
Table 16 – Power factors for short-circuit tests . 51
Table 17 – Overview of test details for the RCM types . 60
Table 18 – Actuating current ranges . 61
Table 19 – Frequency component values of test currents and starting current values
for verifying operating . 62
Table 20 – Operating current ranges for composite residual current. 62
Table 21 – Residual non-operating and operating current according to frequencies that
differ from the rated frequency 50/60 Hz for RCM Type B . 64
Table 22 – EMC tests . 69
Table 23 – Explanation of letter symbols used in Figure 6 to Figure 9 . 77
Table A.1 – Test sequences. 102
Table A.2 – Number of samples submitted to tests . 103
Table A.3 – Tests with a reduced number of samples . 105

– 8 – IEC 62020-1:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
ELECTRICAL ACCESSORIES –
RESIDUAL CURRENT MONITORS (RCMs) –

Part 1: RCMs for household and similar uses

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62020-1 has been prepared by subcommittee 23E:
Circuit-breakers and similar equipment for household use, of IEC technical committee 23:
Electrical accessories.
This first edition cancels and replaces IEC 62020:1998 and IEC 62020:1998/AMD1:2003. This
edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– definition of Type F and Type B RCM;
– marking of Type F and Type B RCM;
– introduction of a new subclause, 8.20;
– modification of 9.7;
– update of 9.9;
– modification of 9.14;
– modification of 9.19, for introduction of the relevant test for Type F and Type B RCM.
The text of this International Standard is based on the following documents:
FDIS Report on voting
23E/1180/FDIS 23E/1183/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 62020 series, published under the general title Electrical
accessories – Residual current monitors (RCMs), can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 10 – IEC 62020-1:2020 © IEC 2020
INTRODUCTION
The purpose of a residual current monitor (hereinafter referred to as RCM) is to monitor an
electrical installation or circuit for the presence of an unbalanced earth fault current and to
indicate, by means of an alarm, the presence of such a residual current when it exceeds a
predetermined level.
Installation and application rules are given in IEC 60364 (all parts).

ELECTRICAL ACCESSORIES –
RESIDUAL CURRENT MONITORS (RCMs) –

Part 1: RCMs for household and similar uses

1 Scope
This document applies to residual current monitors for household and similar purposes,
having rated operational voltages and a rated voltage of the monitored circuit not exceeding
440 V AC and rated currents not exceeding 125 A.
NOTE 1 The standard for residual current monitors having rated operational voltages and a rated voltage of the
monitored circuit exceeding 440 V AC is in preparation, as IEC 62020-2.
RCMs are intended to monitor the residual current of the installation and to give a warning if
the residual current between a live part and an exposed conductive part or earth exceeds a
predetermined level.
RCMs covered by this document are not intended to be used as protective devices.
RCMs detect residual currents circulating in an AC circuit (e.g. residual alternating current,
residual pulsating direct current, residual smooth direct current), whether suddenly applied or
slowly rising.
NOTE 2 RCMs for DC systems are under consideration.
This document applies to monitors performing simultaneously the functions of detection of the
residual current, of comparison of the value of this current with the residual operating current
of the device and providing the specified warning signal(s) when the residual current exceeds
this value.
RCMs supplied by internal batteries are not covered by this document.
The requirements of this document apply for standard conditions (see 7.1). Additional
requirements can be necessary for RCMs used in locations having severe environmental
conditions.
RCMs are intended for use in an environment with pollution degree 2 and overvoltage
category III. For an environment with a higher pollution degree, enclosures giving the
appropriate degree of protection are used.
RCMs in compliance with this document are suitable for use in TN, TT, and IT systems.
This document does not cover Insulation Monitoring Devices (IMDs), which are covered by the
scope of IEC 61557-8.
NOTE 3 An RCM is distinguished from an IMD in that it is passive in its monitoring function and only responds to
an unbalanced fault current in the installation being monitored. An IMD is active in its monitoring and measuring
functions in that it can measure the balanced and unbalanced insulation resistance or impedance in the installation
(see IEC 61557-8).
– 12 – IEC 62020-1:2020 © IEC 2020
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
conten
...