IEC 61643-331:2020
(Main)Components for low-voltage surge protection - Part 331: Performance requirements and test methods for metal oxide varistors (MOV)
Components for low-voltage surge protection - Part 331: Performance requirements and test methods for metal oxide varistors (MOV)
IEC 61643-331:2020 is available as IEC 61643-331:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 61643-331:2020 is a test specification for metal oxide varistors (MOV), which are used for applications up to 1 000 V AC or 1 500 V DC in power lines, or telecommunication, or signalling circuits. They are designed to protect apparatus or personnel, or both, from high transient voltages. This document applies to MOVs having two electrodes and hybrid surge protection components. This document also does not apply to mountings and their effect on the MOV’s characteristics. Characteristics given apply solely to the MOV mounted only in the ways described for the tests. This third edition cancels and replaces the second edition published in 2017. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- a Varistor MCOV rating assurance test;
- an energy rating test (2ms);
- revised Dielectric strength and insulation resistance tests.
Composants pour parafoudres basse tension - Partie 331: Exigences de performance et méthodes d'essai pour les varistances à oxyde métallique (MOV)
IEC 61643-331:2020 est disponible sous forme de IEC 61643-331:2020 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
IEC 61643-331:2020 est une spécification d'essai pour les varistances à oxyde métallique (MOV, Metal Oxide Varistor) utilisées dans des applications jusqu'à 1 000 V en courant alternatif ou 1 500 V en courant continu sur les lignes électriques ou de télécommunication, ou dans les circuits de signalisation. Elles sont conçues pour protéger l'appareillage et/ou le personnel contre les hautes tensions transitoires. Le présent document s'applique aux MOV comportant deux électrodes et des composants pour parafoudres hybrides. Le présent document ne s'applique pas aux montages et à leurs effets sur les caractéristiques des MOV. Les caractéristiques indiquées s'appliquent exclusivement aux MOV montées uniquement dans le sens décrit pour les essais. Cette troisième édition annule et remplace la deuxième édition parue en 2017. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- un essai d'assurance des caractéristiques MCOV assignées de la varistance a été ajouté;
- un essai des caractéristiques assignées d'énergie (2 ms) a été ajouté;
- les essais de rigidité diélectrique et de résistance d'isolement ont été revus.
General Information
Buy Standard
Standards Content (sample)
IEC 61643-331
Edition 3.0 2020-03
INTERNATIONAL
STANDARD
colour
inside
Components for low-voltage surge protection –
Part 331: Performance requirements and test methods for metal oxide varistors
(MOV)
IEC 61643-331:2020-03(en)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2020 IEC, Geneva, Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary
(IEV) online.IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and once 67 000 electrotechnical terminology entries in English and
a month by email. French extracted from the Terms and Definitions clause of IECpublications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or need CISPR.further assistance, please contact the Customer Service
Centre: sales@iec.ch.
---------------------- Page: 2 ----------------------
IEC 61643-331
Edition 3.0 2020-03
INTERNATIONAL
STANDARD
colour
inside
Components for low-voltage surge protection –
Part 331: Performance requirements and test methods for metal oxide varistors
(MOV)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.040.20 ISBN 978-2-8322-7905-2
Warning! Make sure that you obtained this publication from an authorized distributor.
® Registered trademark of the International Electrotechnical Commission---------------------- Page: 3 ----------------------
– 2 – IEC 61643-331:2020 © IEC 2020
CONTENTS
FOREWORD ........................................................................................................................... 5
1 Scope .............................................................................................................................. 7
2 Normative references ...................................................................................................... 7
3 Terms, definitions, symbols and abbreviated terms .......................................................... 8
3.1 Terms and definitions .............................................................................................. 8
3.1.1 Ratings ............................................................................................................ 8
3.1.2 Characteristics................................................................................................. 9
3.2 Symbols and abbreviated terms used in this document ......................................... 11
3.2.1 Symbols ........................................................................................................ 11
3.2.2 Abbreviated terms ......................................................................................... 11
4 Service conditions ......................................................................................................... 12
4.1 Operating and storage temperature ranges ........................................................... 12
4.2 Altitude or atmospheric pressure range ................................................................. 12
4.3 Relative Humidity .................................................................................................. 12
5 Mechanical requirements and materials ......................................................................... 12
5.1 Robustness of terminations ................................................................................... 12
5.2 Solderability .......................................................................................................... 12
5.3 Marking ................................................................................................................. 12
6 General ......................................................................................................................... 13
6.1 Failure rates ......................................................................................................... 13
6.2 Test standard atmospheric conditions ................................................................... 13
7 Electrical requirements .................................................................................................. 13
7.1 Varistor voltage (V ) ............................................................................................. 13
7.2 Maximum AC (DC) continuous voltage (V / V ) ....................................... 13
M(AC) M(DC)7.3 Standby current (I ) .............................................................................................. 13
7.4 Capacitance (C ) .................................................................................................. 13
7.5 Clamping voltage (V ) ........................................................................................... 13
7.6 Electrostatic discharge (ESD) (for SMD type MOV only)........................................ 15
7.7 Rated impulse energy ........................................................................................... 15
7.8 Nominal discharge current (I ) .............................................................................. 15
7.9 Endurance ............................................................................................................ 15
7.10 Limited current temporary overvoltage .................................................................. 15
8 Standard design test criteria .......................................................................................... 16
8.1 General ................................................................................................................. 16
8.2 Ratings ................................................................................................................. 16
8.2.1 Single-impulse maximum current (I ) ........................................................... 16
8.2.2 Next impulse .................................................................................................. 16
8.2.3 Maximum Continuous voltage (V ) ................................................................ 17
8.3 Electrical Characteristics ...................................................................................... 17
8.3.1 Clamping voltage (V ) ................................................................................... 17
8.3.2 Standby current (I ) ...................................................................................... 17
8.3.3 Varistor voltage (V ) ...................................................................................... 17
8.3.4 Capacitance (C ) ........................................................................................... 18
8.3.5 Rated energy ................................................................................................. 18
8.4 Varistor Rating Assurance Testing ........................................................................ 18
---------------------- Page: 4 ----------------------IEC 61643-331:2020 © IEC 2020 – 3 –
8.5 ESD test ............................................................................................................... 19
9 Nominal discharge current and limited current temporary overvoltage............................ 19
9.1 Thermally protected varistors – Sequence of tests ................................................ 19
9.2 Temperature and humidity cycle conditioning ........................................................ 19
9.3 Nominal discharge current (I ) test description ..................................................... 20
9.3.1 General ......................................................................................................... 20
9.3.2 Pass/fail criteria ............................................................................................. 22
9.4 Limited current temporary overvoltage test description and procedure forthermally protected varistors ................................................................................. 22
9.4.1 General ......................................................................................................... 22
9.4.2 Sample preparation ....................................................................................... 23
9.4.3 Test conditions .............................................................................................. 23
9.4.4 Pass/fail criteria ............................................................................................. 23
9.5 Dielectric testing ................................................................................................... 24
9.5.1 Test conditions for thermally protected MOV .................................................. 24
9.5.2 Setup from foil to leads .................................................................................. 25
9.5.3 Pass criteria .................................................................................................. 25
9.6 Insulation Resistance ............................................................................................ 25
Annex A (informative) MOV testing according to the IEC 61643-11:2011 Surgeprotective devices for the Class I, II and III ........................................................................... 26
A.1 General ................................................................................................................. 26
A.2 MOV selection ...................................................................................................... 26
A.3 Cross reference list of abbreviations, descriptions and definitions ......................... 26
A.4 Operating duty test ............................................................................................... 27
A.4.1 General ......................................................................................................... 27
A.4.2 Class I and II operating duty tests (8.4.4.3) ................................................... 32
A.4.3 Additional duty test for test class I ................................................................. 33
A.4.4 Class III operating duty tests ......................................................................... 33
A.4.5 Pass criteria for all operating duty tests and for the additional duty test
for test class I ................................................................................................ 34
A.4.6 Preferred parameters of impulse discharge current I used for Class Iimp
additional duty tests ....................................................................................... 34
A.4.7 Preferred values of impulse discharge current I used for Class I andClass II residual voltage and operating duty tests .......................................... 35
A.4.8 Preferred values of combination generator waveshape used for Class IIItests .............................................................................................................. 35
Annex B (informative) IEC 61051 Varistors for use in electronic equipment ......................... 38
Annex C (normative) Accelerated Endurance screening test ................................................ 39
C.1 Accelerated endurance screening test .................................................................. 39
C.2 Preparation of sample ........................................................................................... 39
C.3 Test conditions ..................................................................................................... 39
C.4 Refer to test circuit diagram as shown in Figure C.1. ............................................ 39
C.5 Pass criteria .......................................................................................................... 40
Annex D (informative) Proposed test method of MTTF – Mean time to failure (MTTF) .......... 41
D.1 Sampling plans ..................................................................................................... 41
D.2 Total test hours ..................................................................................................... 41
D.3 Samples................................................................................................................ 41
D.4 Test set-up ........................................................................................................... 42
D.5 Intermediate measurements .................................................................................. 42
D.6 Failure criteria ....................................................................................................... 42
---------------------- Page: 5 ----------------------– 4 – IEC 61643-331:2020 © IEC 2020
D.7 Acceptance criteria ............................................................................................... 42
Figure 1 – V-I characteristic of an MOV ................................................................................ 10
Figure 2 – Symbol for MOV ................................................................................................... 11
Figure 3 – Symbol for thermally protected MOV .................................................................... 11
Figure 4 – Test circuit for single-impulse maximum current ................................................... 16
Figure 5 – Test circuit for measuring standby current ............................................................ 17
Figure 6 – Test circuit for measuring varistor voltage (V ) .................................................... 18
Figure 7 – Varistor rating assurance test setup ..................................................................... 19
Figure 8 – Nominal discharge current test flowchart .............................................................. 21
Figure 9 – Sequence of the I Test ....................................................................................... 22
Figure 10 – Temporary overvoltage limited current test procedure flowchart ......................... 24
Figure A.1 – Flow chart of the operating duty test ................................................................. 28
Figure A.2 – Test set-up for operating duty test .................................................................... 29
Figure A.3 – Flow chart of testing to determine the measured limiting voltage ....................... 31
Figure A.4 – Operating duty test timing diagram for test classes I and II ............................... 32
Figure A.5 – Additional duty test timing diagram for test class I ............................................ 33
Figure A.6 – Operating duty test timing diagram for test class III ........................................... 34
Figure C.1 – Circuit of accelerated ageing test ...................................................................... 39
Figure D.1 – Test Circuit of MTTF ......................................................................................... 42
Table 1 – Typical Voltage ratings for disc types .................................................................... 14
Table 2 – Typical Voltage Ratings for SMD types .................................................................. 15
Table 3 – Test voltages for dielectric strength Between Test voltage .................................... 25
Table A.1 – Abbreviations, descriptions and definitions ......................................................... 27
Table A.2 – Preferred parameters for class I test .................................................................. 34
Table A.3 – Preferred values for class I and class II tests ..................................................... 35
Table A.4 – Preferred values for class III tests ...................................................................... 36
Table C.1 – Current in V measurement ................................................................................ 39
Table D.1 – Sampling plans .................................................................................................. 41
---------------------- Page: 6 ----------------------IEC 61643-331:2020 © IEC 2020 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMPONENTS FOR LOW-VOLTAGE SURGE PROTECTION –
Part 331: Performance requirements and test methods
for metal oxide varistors (MOV)
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.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 61643-331 has been prepared by subcommittee 37B: Components
for low-voltage surge protection, of IEC technical committee 37: Surge arresters.
This third edition cancels and replaces the second edition published in 2017. This edition
constitutes a technical revision.This edition includes the following significant technical changes with respect to the previous
edition:a) a Varistor MCOV rating assurance test;
b) an energy rating test (2ms);
c) revised Dielectric strength and insulation resistance tests.
---------------------- Page: 7 ----------------------
– 6 – IEC 61643-331:2020 © IEC 2020
The text of this International Standard is based on the following documents:
FDIS Report on voting
37B/211/FDIS 37B/214/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 of IEC 61643 series, under the general title Components for low-voltage
surge protective devices, can be found on the IEC website.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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correctunderstanding of its contents. Users should therefore print this document using a
colour printer.---------------------- Page: 8 ----------------------
IEC 61643-331:2020 © IEC 2020 – 7 –
COMPONENTS FOR LOW-VOLTAGE SURGE PROTECTION –
Part 331: Performance requirements and test methods
for metal oxide varistors (MOV)
1 Scope
This part of IEC 61643 is a test specification for metal oxide varistors (MOV), which are used
for applications up to 1 000 V AC or 1 500 V DC in power lines, or telecommunication, or
signalling circuits. They are designed to protect apparatus or personnel, or both, from high
transient voltages.This document applies to MOVs having two electrodes and hybrid surge protection
components. This document also does not apply to mountings and their effect on the MOV’s
characteristics. Characteristics given apply solely to the MOV mounted only in the ways
described for the tests.2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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.IEC 60068-1:2013, Environmental testing – Part 1: General and guidance
IEC 60068-2-6:2007, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of
temperatureIEC 60068-2-20:2008, Environmental testing – Part 2-20: Tests – Test T: Test methods for
solderability and resistance to soldering heat of devices with leadsIEC 60068-2-21:2006, Environmental testing – Part 2-21: Tests – Test U: Robustness of
terminations and integral mounting devicesIEC 60068-2-27:2008, Environmental testing – Part 2-27: Tests – Test Ea and guidance:
ShockIEC 60068-2-52:2017 Environmental testing – Part 2-52: Tests – Test Kb: Salt mist, cyclic
(sodium chloride solution)IEC 61643-11:2011, Low-voltage surge protective devices – Part 11: Surge protective devices
connected to low-voltage power systems – Requirements and test methodsIEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
---------------------- Page: 9 ----------------------
– 8 – IEC 61643-331:2020 © IEC 2020
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Terms and definitions
3.1.1 Ratings
3.1.1.1
absolute maximum ratings
limiting values of operating and environmental conditions applicable to a component, device,
equipment or machine as defined by its published specification data, which should not be
exceeded under the worst possible conditionsNote 1 to entry: A limiting condition may be either a maximum or a minimum or both.
[SOURCE: IEC 62240-1:2013, 3.1.1, modified ("any semiconductor device of a specific type"
replaced by "a component, device, equipment or machine", addition of Note 1 to entry)]
3.1.1.2single-impulse [transient] maximum current
rated maximum value of current which may be applied for a single impulse of specified
waveformNote 1 to entry: For power distribution SPDs, IEC 61643-11, Maximum Discharge Current I is used.
MAX3.1.1.3
nominal discharge current
crest value of the current through the MOV having a current waveshape of 8/20
3.1.1.4
impulse life characteristic
graphical representation between impulse current peak (I), equivalent rectangular pulse width
(T), and impulse numbers (n) which the MOV can withstandNote 1 to entry: Unless otherwise specified, the range of T shall be 20 µs to 10 ms, the range of n shall be 10 ,
5 4 3 2 1 010 ,10 , 10 , 10 , 10 and 10 .
3.1.1.5
temperature derating curve
graphical representation of parameter derating against temperature
Note 1 to entry: Typical parameters are rated voltage, impulse current, energy and average power dissipation.
3.1.1.6single-pulse [transient] maximum energy
rated maximum value which may be absorbed for a single pulse of a specified waveform
Note 1 to entry: Unless otherwise specified, 2 ms rectangular pulse is used (IEC 60060).
---------------------- Page: 10 ----------------------IEC 61643-331:2020 © IEC 2020 – 9 –
3.1.1.7
maximum continuous voltage
voltage that may be applied continuously at a specified temperature
Note 1 to entry: May also be called U or MCOV.
Note 2 to entry: See Figure 1.
3.1.1.8
maximum continuous AC voltage
M(AC)
value of RMS power frequency voltage (less than 5 % total harmonic distortion) that may be
applied continuously at a specified temperature3.1.1.9
maximum continuous DC voltage
M(DC)
DC voltage that may be applied continuously at a specified temperature
3.1.1.10
mean time to failure
MTTF
basic measure of reliability for non-repairable items, the total number of life units of an item
divided by the total number of failures within that population ,during a particular measurement
interval under stated conditions3.1.2 Characteristics
3.1.2.1
characteristic
inherent and measurable properties of an MOV
3.1.2.2
standby current
current passing through MOV at maximum continuous voltage V
Note 1 to entry: The current passing through the MOV at less than V is called leakage current.
3.1.2.3varistor voltage
voltage across the MOV measured at a specified current (typically 1 mA) for a specific
duration3.1.2.4
varistor test current
test current (typically 1 mA) to determine the varistor voltage V
Note 1 to entry: See Figure 1.
3.1.2.5
clamping voltage
peak voltage across the MOV measured under conditions of a specified peak pulse current
(I ) and specified waveformNote 1 to entry: See Figure 1.
---------------------- Page: 11 ----------------------
– 10 – IEC 61643-331:2020 © IEC 2020
Note 2 to entry: Unless otherwise specified, a typical value of this parameter is measured with a pulsed current
8/20 waveform.Note 3 to entry: Clamping voltage, V , is referred to as measured limiting voltage in IEC 61643-11.
Figure 1 – V-I characteristic of an MOV3.1.2.6
capacitance
capacitance across the MOV measured at a specified frequency, voltage and tim
...
IEC 61643-331
Edition 3.0 2020-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Components for low-voltage surge protection –
Part 331: Performance requirements and test methods for metal oxide varistors
(MOV)
Composants pour parafoudres basse tension –
Partie 331: Exigences de performance et méthodes d'essai pour les varistances
à oxyde métallique (MOV)
IEC 61643-331:2020-03(en-fr)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2020 IEC, Geneva, Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni
utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.
IEC Central Office Tel.: +41 22 919 02 113, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary
(IEV) online.IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and once 67 000 electrotechnical terminology entries in English and
a month by email. French extracted from the Terms and Definitions clause of IECpublications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or need CISPR.further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.
A propos des publications IECLe contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.Recherche de publications IEC - Le premier dictionnaire d'électrotechnologie en ligne au monde,
webstore.iec.ch/advsearchform avec plus de 22 000 articles terminologiques en anglais et en
La recherche avancée permet de trouver des publications IEC français, ainsi que les termes équivalents dans 16 langues
en utilisant différents critères (numéro de référence, texte, additionnelles. Egalement appelé Vocabulaire
comité d’études,…). Elle donne aussi des informations sur les Electrotechnique International (IEV) en ligne.
projets et les publications remplacées ou retirées.Glossaire IEC - std.iec.ch/glossary
IEC Just Published - webstore.iec.ch/justpublished 67 000 entrées terminologiques électrotechniques, en anglais
Restez informé sur les nouvelles publications IEC. Just et en français, extraites des articles Termes et Définitions des
Published détaille les nouvelles publications parues. publications IEC parues depuis 2002. Plus certaines entrées
Disponible en ligne et une fois par mois par email. antérieures extraites des publications des CE 37, 77, 86 et
CISPR de l'IEC.Service Clients - webstore.iec.ch/csc
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
Electropedia - www.electropedia.org
---------------------- Page: 2 ----------------------
IEC 61643-331
Edition 3.0 2020-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Components for low-voltage surge protection –
Part 331: Performance requirements and test methods for metal oxide varistors
(MOV)
Composants pour parafoudres basse tension –
Partie 331: Exigences de performance et méthodes d'essai pour les varistances
à oxyde métallique (MOV)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.040.20 ISBN 978-2-8322-8558-9
Warning! Make sure that you obtained this publication from an authorized distributor.
Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.
® Registered trademark of the International Electrotechnical CommissionMarque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 61643-331:2020 © IEC 2020
CONTENTS
FOREWORD ........................................................................................................................... 5
1 Scope .............................................................................................................................. 7
2 Normative references ...................................................................................................... 7
3 Terms, definitions, symbols and abbreviated terms .......................................................... 8
3.1 Terms and definitions .............................................................................................. 8
3.1.1 Ratings ............................................................................................................ 8
3.1.2 Characteristics................................................................................................. 9
3.2 Symbols and abbreviated terms used in this document ......................................... 11
3.2.1 Symbols ........................................................................................................ 11
3.2.2 Abbreviated terms ......................................................................................... 11
4 Service conditions ......................................................................................................... 12
4.1 Operating and storage temperature ranges ........................................................... 12
4.2 Altitude or atmospheric pressure range ................................................................. 12
4.3 Relative Humidity .................................................................................................. 12
5 Mechanical requirements and materials ......................................................................... 12
5.1 Robustness of terminations ................................................................................... 12
5.2 Solderability .......................................................................................................... 12
5.3 Marking ................................................................................................................. 12
6 General ......................................................................................................................... 13
6.1 Failure rates ......................................................................................................... 13
6.2 Test standard atmospheric conditions ................................................................... 13
7 Electrical requirements .................................................................................................. 13
7.1 Varistor voltage (V ) ............................................................................................. 13
7.2 Maximum AC (DC) continuous voltage (V / V ) ....................................... 13
M(AC) M(DC)7.3 Standby current (I ) .............................................................................................. 13
7.4 Capacitance (C ) .................................................................................................. 13
7.5 Clamping voltage (V ) ........................................................................................... 13
7.6 Electrostatic discharge (ESD) (for SMD type MOV only)........................................ 15
7.7 Rated impulse energy ........................................................................................... 15
7.8 Nominal discharge current (I ) .............................................................................. 15
7.9 Endurance ............................................................................................................ 15
7.10 Limited current temporary overvoltage .................................................................. 15
8 Standard design test criteria .......................................................................................... 16
8.1 General ................................................................................................................. 16
8.2 Ratings ................................................................................................................. 16
8.2.1 Single-impulse maximum current (I ) ........................................................... 16
8.2.2 Next impulse .................................................................................................. 16
8.2.3 Maximum Continuous voltage (V ) ................................................................ 17
8.3 Electrical Characteristics ...................................................................................... 17
8.3.1 Clamping voltage (V ) ................................................................................... 17
8.3.2 Standby current (I ) ...................................................................................... 17
8.3.3 Varistor voltage (V ) ...................................................................................... 17
8.3.4 Capacitance (C ) ........................................................................................... 18
8.3.5 Rated energy ................................................................................................. 18
8.4 Varistor Rating Assurance Testing ........................................................................ 18
8.5 ESD test ............................................................................................................... 19
---------------------- Page: 4 ----------------------IEC 61643-331:2020 © IEC 2020 – 3 –
9 Nominal discharge current and limited current temporary overvoltage............................ 19
9.1 Thermally protected varistors – Sequence of tests ................................................ 19
9.2 Temperature and humidity cycle conditioning ........................................................ 19
9.3 Nominal discharge current (I ) test description ..................................................... 20
9.3.1 General ......................................................................................................... 20
9.3.2 Pass/fail criteria ............................................................................................. 22
9.4 Limited current temporary overvoltage test description and procedure forthermally protected varistors ................................................................................. 22
9.4.1 General ......................................................................................................... 22
9.4.2 Sample preparation ....................................................................................... 23
9.4.3 Test conditions .............................................................................................. 23
9.4.4 Pass/fail criteria ............................................................................................. 23
9.5 Dielectric testing ................................................................................................... 24
9.5.1 Test conditions for thermally protected MOV .................................................. 24
9.5.2 Setup from foil to leads .................................................................................. 25
9.5.3 Pass criteria .................................................................................................. 25
9.6 Insulation Resistance ............................................................................................ 25
Annex A (informative) MOV testing according to the IEC 61643-11:2011 Surgeprotective devices for the Class I, II and III ........................................................................... 26
A.1 General ................................................................................................................. 26
A.2 MOV selection ...................................................................................................... 26
A.3 Cross reference list of abbreviations, descriptions and definitions ......................... 26
A.4 Operating duty test ............................................................................................... 27
A.4.1 General ......................................................................................................... 27
A.4.2 Class I and II operating duty tests (8.4.4.3) ................................................... 32
A.4.3 Additional duty test for test class I ................................................................. 33
A.4.4 Class III operating duty tests ......................................................................... 33
A.4.5 Pass criteria for all operating duty tests and for the additional duty test
for test class I ................................................................................................ 34
A.4.6 Preferred parameters of impulse discharge current I used for Class Iimp
additional duty tests ....................................................................................... 34
A.4.7 Preferred values of impulse discharge current I used for Class I andClass II residual voltage and operating duty tests .......................................... 35
A.4.8 Preferred values of combination generator waveshape used for Class IIItests .............................................................................................................. 36
Annex B (informative) IEC 61051 Varistors for use in electronic equipment ......................... 38
Annex C (normative) Accelerated Endurance screening test ................................................ 39
C.1 Accelerated endurance screening test .................................................................. 39
C.2 Preparation of sample ........................................................................................... 39
C.3 Test conditions ..................................................................................................... 39
C.4 Refer to test circuit diagram as shown in Figure C.1. ............................................ 39
C.5 Pass criteria .......................................................................................................... 40
Annex D (informative) Proposed test method of MTTF – Mean time to failure (MTTF) .......... 41
D.1 Sampling plans ..................................................................................................... 41
D.2 Total test hours ..................................................................................................... 41
D.3 Samples................................................................................................................ 41
D.4 Test set-up ........................................................................................................... 42
D.5 Intermediate measurements .................................................................................. 42
D.6 Failure criteria ....................................................................................................... 42
D.7 Acceptance criteria ............................................................................................... 42
---------------------- Page: 5 ----------------------– 4 – IEC 61643-331:2020 © IEC 2020
Figure 1 – V-I characteristic of an MOV ................................................................................ 10
Figure 2 – Symbol for MOV ................................................................................................... 11
Figure 3 – Symbol for thermally protected MOV .................................................................... 11
Figure 4 – Test circuit for single-impulse maximum current ................................................... 16
Figure 5 – Test circuit for measuring standby current ............................................................ 17
Figure 6 – Test circuit for measuring varistor voltage (V ) ..................................................... 18
Figure 7 – Varistor rating assurance test setup ..................................................................... 19
Figure 8 – Nominal discharge current test flowchart .............................................................. 21
Figure 9 – Sequence of the I Test ....................................................................................... 22
Figure 10 – Temporary overvoltage limited current test procedure flowchart ......................... 24
Figure A.1 – Flow chart of the operating duty test ................................................................. 28
Figure A.2 – Test set-up for operating duty test .................................................................... 29
Figure A.3 – Flow chart of testing to determine the measured limiting voltage ....................... 31
Figure A.4 – Operating duty test timing diagram for test classes I and II ............................... 32
Figure A.5 – Additional duty test timing diagram for test class I ............................................ 33
Figure A.6 – Operating duty test timing diagram for test class III ........................................... 34
Figure C.1 – Circuit of accelerated ageing test ...................................................................... 39
Figure D.1 – Test Circuit of MTTF ......................................................................................... 42
Table 1 – Typical Voltage ratings for disc types .................................................................... 14
Table 2 – Typical Voltage Ratings for SMD types .................................................................. 15
Table 3 – Test voltages for dielectric strength Between Test voltage .................................... 25
Table A.1 – Abbreviations, descriptions and definitions ......................................................... 27
Table A.2 – Preferred parameters for class I test .................................................................. 34
Table A.3 – Preferred values for class I and class II tests ..................................................... 35
Table A.4 – Preferred values for class III tests ...................................................................... 36
Table C.1 – Current in V measurement ................................................................................ 39
Table D.1 – Sampling plans .................................................................................................. 41
---------------------- Page: 6 ----------------------IEC 61643-331:2020 © IEC 2020 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMPONENTS FOR LOW-VOLTAGE SURGE PROTECTION –
Part 331: Performance requirements and test methods
for metal oxide varistors (MOV)
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.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 61643-331 has been prepared by subcommittee 37B: Components
for low-voltage surge protection, of IEC technical committee 37: Surge arresters.
This third edition cancels and replaces the second edition published in 2017. This edition
constitutes a technical revision.This edition includes the following significant technical changes with respect to the previous
edition:a) a Varistor MCOV rating assurance test;
b) an energy rating test (2ms);
c) revised Dielectric strength and insulation resistance tests.
---------------------- Page: 7 ----------------------
– 6 – IEC 61643-331:2020 © IEC 2020
The text of this International Standard is based on the following documents:
FDIS Report on voting
37B/211/FDIS 37B/214/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 of IEC 61643 series, under the general title Components for low-voltage
surge protective devices, can be found on the IEC website.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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correctunderstanding of its contents. Users should therefore print this document using a
colour printer.---------------------- Page: 8 ----------------------
IEC 61643-331:2020 © IEC 2020 – 7 –
COMPONENTS FOR LOW-VOLTAGE SURGE PROTECTION –
Part 331: Performance requirements and test methods
for metal oxide varistors (MOV)
1 Scope
This part of IEC 61643 is a test specification for metal oxide varistors (MOV), which are used
for applications up to 1 000 V AC or 1 500 V DC in power lines, or telecommunication, or
signalling circuits. They are designed to protect apparatus or personnel, or both, from high
transient voltages.This document applies to MOVs having two electrodes and hybrid surge protection
components. This document also does not apply to mountings and their effect on the MOV’s
characteristics. Characteristics given apply solely to the MOV mounted only in the ways
described for the tests.2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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.IEC 60068-1:2013, Environmental testing – Part 1: General and guidance
IEC 60068-2-6:2007, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of
temperatureIEC 60068-2-20:2008, Environmental testing – Part 2-20: Tests – Test T: Test methods for
solderability and resistance to soldering heat of devices with leadsIEC 60068-2-21:2006, Environmental testing – Part 2-21: Tests – Test U: Robustness of
terminations and integral mounting devicesIEC 60068-2-27:2008, Environmental testing – Part 2-27: Tests – Test Ea and guidance:
ShockIEC 60068-2-52:2017 Environmental testing – Part 2-52: Tests – Test Kb: Salt mist, cyclic
(sodium chloride solution)IEC 61643-11:2011, Low-voltage surge protective devices – Part 11: Surge protective devices
connected to low-voltage power systems – Requirements and test methodsIEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
---------------------- Page: 9 ----------------------
– 8 – IEC 61643-331:2020 © IEC 2020
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Terms and definitions
3.1.1 Ratings
3.1.1.1
absolute maximum ratings
limiting values of operating and environmental conditions applicable to a component, device,
equipment or machine as defined by its published specification data, which should not be
exceeded under the worst possible conditionsNote 1 to entry: A limiting condition may be either a maximum or a minimum or both.
[SOURCE: IEC 62240-1:2013, 3.1.1, modified ("any semiconductor device of a specific type"
replaced by "a component, device, equipment or machine", addition of Note 1 to entry)]
3.1.1.2single-impulse [transient] maximum current
rated maximum value of current which may be applied for a single impulse of specified
waveformNote 1 to entry: For power distribution SPDs, IEC 61643-11, Maximum Discharge Current I is used.
MAX3.1.1.3
nominal discharge current
crest value of the current through the MOV having a current waveshape of 8/20
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.