IEC 61643-331:2017

Components for low-voltage surge protective devices - Part 331: Performance requirements and test methods for metal oxide varistors (MOV)

IEC 61643-331:2017 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 line, or telecommunication, or signalling circuits. They are designed to protect apparatus or personnel, or both, from high transient voltages. This specification applies to MOVs having two electrodes and hybrid overvoltage protection components. This specification 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 second edition cancels and replaces the first edition published in 2003. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) Update of the nominal varistor voltage test method;
b) Addition of thermally protected varistors – component symbol and test methods;
c) Addition of nominal discharge current – test methods;
d) Addition of voltage ratings for disc types (Table 1);
e) Addition of test currents for clamping voltage of disc types (Table 2);
f) Addition of typical voltage ratings of SMD types (Table 3); and
g) Addition of Limited current and temporary overvoltage tests for thermally protected varistors.
Keywords: metal oxide varistors (MOV), high transient voltages.

Composants pour parafoudres basse tension - Partie 331: Exigences de performances et méthodes d'essai pour varistances à oxyde métallique (VOM)

IEC 61643-331:2017 traite des spécifications d'essais relatifs aux varistances à oxyde métallique (VOM), utilisées pour des applications sur des lignes d'alimentation, de télécommunication ou des circuits de signalisation de 1 000 V CA ou 1 500 V CC au plus. Elles sont conçues pour protéger le matériel, le personnel ou les deux des tensions transitoires élevées. Ces spécifications s'appliquent aux VOM qui disposent de deux électrodes et de composants hybrides de protection contre la surtension. Par ailleurs, ces spécifications ne s'appliquent pas aux supports de fixation et à leur effet sur les caractéristiques des VOM. Les caractéristiques présentées ne s'appliquent qu'aux VOM montées selon les méthodes décrites pour les essais. Cette deuxième édition annule et remplace la première édition parue en 2003. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) mise à jour de la méthode d'essai de tension nominale de varistance;
b) ajout des varistances à protection thermique – symbole de composant et méthodes d'essai;
c) ajout du courant nominal de décharge – méthodes d'essai;
d) ajout de caractéristiques de tensions pour les types à disques (Tableau 1);
e) ajout de courants d'essai pour la tension d'écrêtage des types à disques (Tableau 2);
f) ajout de caractéristiques de tensions typiques des types de CMS (Tableau 3); et
g) ajout d'essais en courants limités et surtensions temporaires pour les varistances à protection thermique.
Mots clés : varistances à oxyde métallique (VOM), tensions transitoires élevées

General Information

• Status: Published
• Publication Date: 06-Dec-2017
• ICS: 31.040.20 - Potentiometers, variable resistors
• Technical Committee: SC 37B - Components for low-voltage surge protection
• Drafting Committee: MT 1 - TC 37/SC 37B/MT 1
• Current Stage: DELPUB - Deleted Publication
• Start Date: 19-Oct-2018
• Completion Date: 19-Mar-2020

Relations

• Revised: IEC 61643-331:2020 - Components for low-voltage surge protection - Part 331: Performance requirements and test methods for metal oxide varistors (MOV)
• Effective Date: 05-Sep-2023
• Revises: IEC 61643-331:2003 - Components for low-voltage surge protective devices - Part 331: Specification for metal oxide varistors (MOV)
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61643-331 ®
Edition 2.0 2017-12
INTERNATIONAL
STANDARD
colour
inside
Components for low-voltage surge protective devices –
Part 331: Performance requirements and test methods for metal oxide varistors
(MOV)
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.

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3, rue de Varembé Fax: [phone]

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Switzerland www.iec.ch
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IEC 61643-331 ®
Edition 2.0 2017-12
INTERNATIONAL
STANDARD
colour
inside
Components for low-voltage surge protective devices –

Part 331: Performance requirements and test methods for metal oxide varistors

(MOV)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.040.20 ISBN 978-2-8322-5095-2

– 2 – IEC 61643-331:2017 © IEC 2017

CONTENTS
CONTENTS . 2

FOREWORD . 5

1 Scope . 7

2 Normative references . 7

3 Terms, definitions, symbols and abbreviated terms . 7

3.1 Ratings . 8

3.2 Characteristics . 9

3.3 Symbols . 10
3.4 Abbreviated terms . 11
4 Service conditions . 11
4.1 Operating and storage temperature ranges . 11
4.2 Altitude or atmospheric pressure range . 11
4.3 Relative Humidity . 11
5 Mechanical requirements and materials . 12
5.1 Robustness of terminations . 12
5.2 Solderability . 12
5.3 Marking . 12
6 General . 12
6.1 Failure rates . 12
6.2 Test standard atmospheric conditions . 12
7 Electrical requirements . 12
7.1 Nominal varistor voltage . 12
7.2 Maximum AC (DC) continuous operating voltage. 13
7.3 Standby current I . 13
DC
7.4 Capacitance . 13
7.5 Clamping voltage . 13
7.6 Electrostatic discharge (ESD) (for SMD type MOV only). 15
7.7 Rated impulse energy (W ) . 15
TM
7.8 Nominal discharge current I . 15
n
7.9 Endurance . 15
7.10 Limited current temporary overvoltage . 15
8 Standard design test criteria . 15

8.1 General . 15
8.2 Ratings . 15
8.2.1 Single-impulse maximum current (I ) . 15
TM
8.2.2 Next Impulse . 16
8.2.3 Continuous rated voltage (V ) . 16
M
8.3 Electrical characteristics . 16
8.3.1 Clamping voltage (V ) . 16
C
8.3.2 Standby current (I ) . 17
D
8.3.3 Nominal varistor voltage (V ) . 17
N
8.3.4 Capacitance (C ) . 17
V
8.4 Endurance . 18
8.5 ESD Test Method . 18
9 Nominal discharge current and limited current temporary overvoltage. 18

9.1 Thermally protected varistors – Sequence of tests . 18

9.2 Temperature and humidity cycle conditioning . 18

9.3 Nominal discharge current I(n) test description . 19

9.3.1 General . 19

9.3.2 Pass/fail criteria . 21

9.4 Limited current temporary overvoltage test description and procedure for

thermally protected varistors . 21

9.4.1 General . 21

9.4.2 Sample preparation . 21

9.4.3 Test conditions . 21

9.4.4 Pass/fail criteria . 22
9.5 Dielectric testing . 24
9.5.1 Test conditions . 24
9.5.2 Setup from foil to leads . 24
9.5.3 Pass criteria . 24
Annex A (informative) MOV testing according to IEC 61643-11:2011 – Surge
protective devices for the Class I, II and III . 25
A.1 General . 25
A.2 MOV selection . 25
A.3 Cross reference list of abbreviations, descriptions and definitions . 25
A.4 Operating duty test . 26
A.4.1 General . 26
A.4.2 Measured limiting voltage . 28
A.4.3 Class I and II operating duty tests (8.3.4.3) . 31
A.4.4 Additional duty test for test class I . 31
A.4.5 Class III operating duty tests . 32
A.4.6 Pass criteria for all operating duty tests and for the additional duty test
for test class I . 33
A.4.7 Preferred parameters of impulse discharge current I used for Class I

imp
additional duty tests . 33
A.4.8 Preferred values of impulse discharge current I used for Class I and
n
Class II residual voltage and operating duty tests . 33
A.4.9 Preferred values of combination waveshape used for Class III tests . 34
Annex B (informative) IEC 61051 Varistors for use in electronic equipment . 36
Annex C (informative) Accelerated endurance screening test . 37
C.1 Accelerated endurance screening test . 37

C.2 Preparation of sample . 37
C.3 Test conditions . 37
C.4 Pass criteria . 38
Annex D (informative) Proposed test method for determination of mean time to failure
(MTTF) . 39
D.1 Sampling plans . 39
D.2 Total test hours . 39
D.3 Samples. 39
D.4 Intermediate measurements . 40
D.5 Failure criteria . 40
D.6 Acceptance criteria . 40
Bibliography .
...

IEC 61643-331 ®
Edition 2.0 2017-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Components for low-voltage surge protective devices –
Part 331: Performance requirements and test methods for metal oxide
varistors (MOV)
Composants pour parafoudres basse tension –
Partie 331: Exigences de performances et méthodes d'essai pour varistances
à oxyde métallique (VOM)
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

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International Standards for all electrical, electronic and related technologies.

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latest edition, a corrigendum or an amendment might have been published.

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IEC 61643-331 ®
Edition 2.0 2017-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Components for low-voltage surge protective devices –

Part 331: Performance requirements and test methods for metal oxide

varistors (MOV)
Composants pour parafoudres basse tension –

Partie 331: Exigences de performances et méthodes d'essai pour varistances

à oxyde métallique (VOM)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.040.20 ISBN 978-2-8322-6824-7

– 2 – IEC 61643-331:2017 © IEC 2017

CONTENTS
CONTENTS . 2

FOREWORD . 5

1 Scope . 7

2 Normative references . 7

3 Terms, definitions, symbols and abbreviated terms . 7

3.1 Ratings . 8

3.2 Characteristics . 9

3.3 Symbols . 10
3.4 Abbreviated terms . 11
4 Service conditions . 11
4.1 Operating and storage temperature ranges . 11
4.2 Altitude or atmospheric pressure range . 11
4.3 Relative Humidity . 11
5 Mechanical requirements and materials . 12
5.1 Robustness of terminations . 12
5.2 Solderability . 12
5.3 Marking . 12
6 General . 12
6.1 Failure rates . 12
6.2 Test standard atmospheric conditions . 12
7 Electrical requirements . 12
7.1 Nominal varistor voltage . 12
7.2 Maximum AC (DC) continuous operating voltage. 13
7.3 Standby current I . 13
DC
7.4 Capacitance . 13
7.5 Clamping voltage . 13
7.6 Electrostatic discharge (ESD) (for SMD type MOV only). 15
7.7 Rated impulse energy (W ) . 15
TM
7.8 Nominal discharge current I . 15
n
7.9 Endurance . 15
7.10 Limited current temporary overvoltage . 15
8 Standard design test criteria . 15

8.1 General . 15
8.2 Ratings . 15
8.2.1 Single-impulse maximum current (I ) . 15
TM
8.2.2 Next Impulse . 16
8.2.3 Continuous rated voltage (V ) . 16
M
8.3 Electrical characteristics . 16
8.3.1 Clamping voltage (V ) . 16
C
8.3.2 Standby current (I ) . 17
D
8.3.3 Nominal varistor voltage (V ) . 17
N
8.3.4 Capacitance (C ) . 17
V
8.4 Endurance . 18
8.5 ESD Test Method . 18
9 Nominal discharge current and limited current temporary overvoltage. 18

9.1 Thermally protected varistors – Sequence of tests . 18

9.2 Temperature and humidity cycle conditioning . 18

9.3 Nominal discharge current I(n) test description . 19

9.3.1 General . 19

9.3.2 Pass/fail criteria . 21

9.4 Limited current temporary overvoltage test description and procedure for

thermally protected varistors . 21

9.4.1 General . 21

9.4.2 Sample preparation . 21

9.4.3 Test conditions . 21

9.4.4 Pass/fail criteria . 22
9.5 Dielectric testing . 24
9.5.1 Test conditions . 24
9.5.2 Setup from foil to leads . 24
9.5.3 Pass criteria . 24
Annex A (informative) MOV testing according to IEC 61643-11:2011 – Surge
protective devices for the Class I, II and III . 25
A.1 General . 25
A.2 MOV selection . 25
A.3 Cross reference list of abbreviations, descriptions and definitions . 25
A.4 Operating duty test . 26
A.4.1 General . 26
A.4.2 Measured limiting voltage . 28
A.4.3 Class I and II operating duty tests (8.3.4.3) . 31
A.4.4 Additional duty test for test class I .
...