IEC 60691:2002

Thermal-links - Requirements and application guide

Applies to thermal-links, intended for incorporation in electrical appliances, electronic equipment and component parts thereof, normally intended for use indoors, in order to protect them against excessive temperatures under abnormal conditions. May be applicable to thermal-links for use under other than indoor conditions, provided that the climatic and other circumstances in the immediate surroundings of such thermal-links are comparable with those in this standard.

Protecteurs thermiques - Prescriptions et guide d'application

Applies to thermal-links, intended for incorporation in electrical appliances, electronic equipment and component parts thereof, normally intended for use indoors, in order to protect them against excessive temperatures under abnormal conditions. May be applicable to thermal-links for use under other than indoor conditions, provided that the climatic and other circum- stances in the immediate surroundings of such thermal-links are comparable with those in this standard.

General Information

• Status: Published
• Publication Date: 24-Feb-2010
• ICS: 29.120.50 - Fuses and other overcurrent protection devices
• Technical Committee: SC 32C - Miniature fuses
• Drafting Committee: MT 9 - TC 32/SC 32C/MT 9
• Current Stage: DELPUB - Deleted Publication
• Start Date: 08-Oct-2015
• Completion Date: 26-Oct-2025

Relations

• Amended By: IEC 60691:2002/AMD1:2006 - Amendment 1 - Thermal-links - Requirements and application guide
• Effective Date: 05-Sep-2023
• Amended By: IEC 60691:2002/AMD2:2010 - Amendment 2 - Thermal-links - Requirements and application guide
• Effective Date: 05-Sep-2023
• Revises: IEC 60691:1993 - Thermal-links - Requirements and application guide
• Effective Date: 05-Sep-2023
• Revised: IEC 60691:2015 - Thermal-links - Requirements and application guide
• Effective Date: 05-Sep-2023
• Revises: IEC 60691:1993/AMD2:2000 - Amendment 2 - Thermal-links - Requirements and application guide
• Effective Date: 05-Sep-2023

Overview

IEC 60691:2002, titled Thermal-links – Requirements and Application Guide, is an international standard published by the International Electrotechnical Commission (IEC). It specifies uniform requirements, test methods, and guidance for the application of thermal-links in electrical appliances, electronic equipment, and their components. Typically intended for indoor use, thermal-links provide critical protection against excessive temperatures caused by abnormal conditions. The standard applies to thermal-links rated up to 690 V a.c./d.c. with a current rating up to 63 A.

Thermal-links are non-resettable devices designed to function once by interrupting excessive heat to prevent damage or hazard. This standard addresses their mechanical, electrical, and thermal characteristics to ensure safe and reliable operation within the defined scope.

Key Topics

• Scope and Object
  IEC 60691 covers thermal-links used predominantly indoors but may extend to equivalent climatic conditions outdoors. It excludes use under extreme atmospheres (corrosive/explosive) or frequencies outside 45–62 Hz. The standard also clarifies limitations on thermal-link shapes, molten material behavior, and mounting considerations.

• General Requirements
  The document establishes mechanical strength, electrical insulation, and temperature tolerance criteria. It defines classification schemes based on rated voltage, current, and temperature performance essential for product consistency.

• Testing Methods
  Detailed test procedures ensure compliance: mechanical stress tests (tensile, bending), electrical tests (dielectric strength, current interruption), temperature endurance (aging, holding temperature), and resistance to rusting. Annexes provide specific test guides such as conductive heat aging or seal aging tests.

• Marking and Documentation
  Proper marking for identification, including rated values and compliance symbols, are mandated. Documentation requirements support traceability and conformity assessment.

• Application Guidance
  Practical advice included on mounting positions, adjustment of creepage distances to meet equipment standards, and application under various environmental conditions.

Applications

IEC 60691 thermal-links find many applications in:

• Electrical Appliances
  Thermal protection in heaters, irons, coffee machines, and other household devices to prevent overheating.

• Electronic Equipment
  Safeguarding power supplies, transformers, and circuit components from temperature-induced failures.

• Component Parts
  Integration in sub-assemblies or modules requiring thermal cutoff features to enhance safety and reliability.

• Indoor Use Scenarios
  Designed primarily for indoor environments, thermal-links ensure safe operation consistent with climatic assumptions of the standard.

• Special Conditions
  With due consideration to local environmental factors, this standard may guide thermal-link application even in some outdoor or harsher conditions.

Related Standards

IEC 60691 complements other international standards related to electrical safety and thermal protection, including:

• UL 1020 - The former U.S. standard for thermal cutoffs which served as a foundational reference during IEC 60691's development.

• IEC 60335 series - Standards concerning the safety of household and similar electrical appliances, often specifying creepage distances and insulation requirements intersecting with thermal-link usage.

• IEC 60269 series - Standard for low-voltage fuses, which are functionally related to miniature fuses and thermal-links in electrical protection.

• IEC 60068 series - Environmental testing standards relevant to assessing thermal-link performance under varying conditions.

Practical Value

Adopting IEC 60691 ensures thermal-link manufacturers and equipment designers:

• Achieve consistent product safety and quality by following internationally agreed test methods.

• Benefit from clear product classification facilitating proper selection for specific voltage, current, and temperature requirements.

• Comply with marking and documentation standards enhancing traceability and compliance verification.

• Rely on informed application guidance to optimize thermal protection and reduce risk of equipment damage or fire hazards.

Incorporation of this standard ultimately contributes to enhanced reliability, safety, and user protection in electrical and electronic equipment where temperature control is critical.

Standards Content (Sample)

NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Troisième édition
STANDARD
Third edition
2002-12
Protecteurs thermiques –
Prescriptions et guide d'application
Thermal-links –
Requirements and application guide
Numéro de référence
Reference number
CEI/IEC 60691:2002
Numérotation des publications Publication numbering
Depuis le 1er janvier 1997, les publications de la CEI As from 1 January 1997 all IEC publications are
sont numérotées à partir de 60000. Ainsi, la CEI 34-1 issued with a designation in the 60000 series. For
devient la CEI 60034-1. example, IEC 34-1 is now referred to as IEC 60034-1.
Editions consolidées Consolidated editions
Les versions consolidées de certaines publications de la The IEC is now publishing consolidated versions of its
CEI incorporant les amendements sont disponibles. Par publications. For example, edition numbers 1.0, 1.1
exemple, les numéros d’édition 1.0, 1.1 et 1.2 indiquent and 1.2 refer, respectively, to the base publication,
respectivement la publication de base, la publication de the base publication incorporating amendment 1 and
base incorporant l’amendement 1, et la publication de the base publication incorporating amendments 1
base incorporant les amendements 1 et 2. and 2.
Informations supplémentaires Further information on IEC publications
sur les publications de la CEI
Le contenu technique des publications de la CEI est The technical content of IEC publications is kept
constamment revu par la CEI afin qu'il reflète l'état under constant review by the IEC, thus ensuring that
actuel de la technique. Des renseignements relatifs à the content reflects current technology. Information
cette publication, y compris sa validité, sont dispo- relating to this publication, including its validity, is
nibles dans le Catalogue des publications de la CEI available in the IEC Catalogue of publications
(voir ci-dessous) en plus des nouvelles éditions, (see below) in addition to new editions, amendments
amendements et corrigenda. Des informations sur les and corrigenda. Information on the subjects under
sujets à l’étude et l’avancement des travaux entrepris consideration and work in progress undertaken by the
par le comité d’études qui a élaboré cette publication, technical committee which has prepared this
ainsi que la liste des publications parues, sont publication, as well as the list of publications issued,
également disponibles par l’intermédiaire de: is also available from the following:
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NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Troisième édition
STANDARD
Third edition
2002-12
Protecteurs thermiques –
Prescriptions et guide d'application
Thermal-links –
Requirements and application guide
 IEC 2002 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail]  Web: www.iec.ch
CODE PRIX
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Commission Electrotechnique Internationale PRICE CODE
International Electrotechnical Commission
Международная Электротехническая Комиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

– 2 – 60691  CEI:2002
SOMMAIRE
AVANT-PROPOS . 4
INTRODUCTION .8
1 Domaine d'application.10
2 Références normatives .12
3 Définitions .14
4 Prescriptions générales .16
5 Conditions générales d'essais.18
6 Classification .22
7 Marquage .22
8 Documentation.24
9 Prescriptions d'ordre mécanique .24
10 Prescriptions d'ordre électrique.32
11 Essais de température .46
12 Protection contre la rouille .48
Annexe A (normative) Guide d'application .52
Annexe B (normative) Variante d'essai de vieillissement pour les protecteurs
thermiques avec T plus grand que 250 °C pour utilisation dans les fers électriques.54
h
Annexe C (normative) Essai de vieillissement après exposition à une chaleur conductrice.56
Annexe D (informative) Evaluation de la tenue de température étendue .66
Annexe E (normative) Essai de vieillissement des enrobages .70
Annexe F (normative) Prescriptions d’identification .74
Annexe G (informative) Indélébilité du marquage .76
Figure 1 – Essai de torsion.30
Figure C.1 – Ensemble fixe d’essai typique .62
Figure C.2 – Etuve typique d’essai de protecteur thermique .64
Figure D.1 – Support typique de bornes d’essai fixes .68
Figure E.1 – Temps de conditionnement contre température de l’étuve pour des index
de température proposés .72
Figure G.1 – Appareil pour vérifier l'indélébilité des marquages .76
Tableau 1 – Programme d'essais .20
Tableau 2 – Robustesse des bornes – Valeurs des efforts de traction et de poussée
minimaux prescrits .32
Tableau 3 – Lignes de fuite et distances d'isolement (valeurs minimales absolues).34
Tableau 4 – Tensions d'essai pour la rigidité diélectrique.36
Tableau 5 – Courant d’essai pour courant de coupure.40
Tableau 6 – Pouvoir de l’essai de court-circuit limité .44

60691  IEC:2002 – 3 –
CONTENTS
FOREWORD . 5
INTRODUCTION .9
1 Scope .11
2 Normative references.13
3 Definitions .15
4 General requirements .17
5 General notes on tests.19
6 Classification .23
7 Marking .23
8 Documentation.25
9 Mechanical requirements .25
10 Electrical requirements .33
11 Temperature tests.47
12 Resistance to rusting .49
Annex A (normative) Application guide.53
Annex B (normative) Alternative ageing test for thermal-links with T
h
greater than 250 °C for use in electric irons .55
Annex C (normative) Conductive heat ageing test .57
Annex D (informative) Extended holding temperature evaluation .67
Annex E (normative) Seal ageing test .71
Annex F (normative) Identification requirements.75
Annex G (informative) Indelibility of markings .77
Figure 1 – Bending/twist test .31
Figure C.1 – Typical test fixture assembly .63
Figure C.2 – Typical thermal-link test oven.65
Figure D.1 – Typical terminal block support test fixture .69
Figure E.1 – Conditioning time versus oven temperature for proposed temperature index .73
Figure G.1 – Apparatus for testing durability of markings .77
Table 1 – Test schedule .21
Table 2 – Strength of terminals – Minimum required tensile and thrust test forces.33
Table 3 – Creepage distances and clearances (absolute minimum values).35
Table 4 – Test voltages for dielectric strength .37
Table 5 – Test current for interrupting test.41
Table 6 – Limited short-circuit test capacity.45

– 4 – 60691  CEI:2002
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
____________
PROTECTEURS THERMIQUES –
PRESCRIPTIONS ET GUIDE D'APPLICATION
AVANT-PROPOS
1) La CEI (Commission Électrotechnique Internationale) est une organisation mondiale de normalisation
composée de l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a
pour objet de favoriser la coopération internationale pour toutes les questions de normalisation dans les
domaines de l'électricité et de l'électronique. A cet effet, la CEI, entre autres activités, publie des Normes
internationales. Leur élaboration est confiée à des comités d'études, aux travaux desquels tout Comité national
intéressé par le sujet traité peut participer. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec la CEI, participent également aux travaux. La CEI collabore étroitement
avec l'Organisation Internationale de Normalisation (ISO), selon des conditions fixées par accord entre les
deux organisations.
2) Les décisions ou accords officiels de la CEI concernant les questions techniques représentent, dans la mesure
du possible, un accord international sur les sujets étudiés, étant donné que les Comités nationaux intéressés
sont représentés dans chaque comité d’études.
3) Les documents produits se présentent sous la forme de recommandations internationales. Ils sont publiés
comme normes, spécifications techniques, rapports techniques ou guides et agréés comme tels par les
Comités nationaux.
4) Dans le but d'encourager l'unification internationale, les Comités nationaux de la CEI s'engagent à appliquer de
façon transparente, dans toute la mesure possible, les Normes internationales de la CEI dans leurs normes
nationales et régionales. Toute divergence entre la norme de la CEI et la norme nationale ou régionale
correspondante doit être indiquée en termes clairs dans cette dernière.
5) La CEI n’a fixé aucune procédure concernant le marquage comme indication d’approbation et sa responsabilité
n’est pas engagée quand un matériel est déclaré conforme à l’une de ses normes.
6) L’attention est attirée sur le fait que certains des éléments de la présente Norme internationale peuvent faire
l’objet de droits de propriété intellectuelle ou de droits analogues. La CEI ne saurait être tenue pour
responsable de ne pas avoir identifié de tels droits de propriété et de ne pas avoir signalé leur existence.
La Norme internationale CEI 60691 a été établie par le sous-comité 32C: Coupe-circuit à
fusibles miniatures, du comité d'études 32 de la CEI: Coupe-circuit à fusibles.
Cette troisième édition annule et remplace la deuxième édition publiée en 1993, l’amende-
ment 1 (1995) et l’amendement 2 (2000). Cette troisième édition constitue une révision
technique.
Le texte de cette norme est issu des documents suivants:
FDIS Rapport de vote
32C/321/FDIS 32C/329/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant
abouti à l'approbation de cette norme.
Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2.
La norme nationale américaine UL 1020 (cinquième édition), qui traite des coupe-circuit
thermiques/protecteurs thermiques, a servi de base à l'élaboration de cette nouvelle édition.

60691  IEC:2002 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
THERMAL-LINKS –
REQUIREMENTS AND APPLICATION GUIDE
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60691 has been prepared by subcommittee 32C: Miniature fuses,
of IEC technical committee 32: Fuses.
This third edition cancels and replaces the second edition published in 1993, its amendment 1
(1995) and its amendment 2 (2000). This third edition constitutes a technical revision.
The text of this standard is based on the following documents:
FDIS Report on voting
32C/321/FDIS 32C/329/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The US national standard UL 1020 (fifth edition) which deals with thermal cutoffs/thermal-
links, has served as a basis for the elaboration of this new edition.

– 6 – 60691  CEI:2002
Le comité a décidé que le contenu de cette publication ne sera pas modifié avant 2005. A
cette date, la publication sera
• reconduite;
• supprimée;
• remplacée par une édition révisée, ou
• amendée.
60691  IEC:2002 – 7 –
The committee has decided that the contents of this publication will remain unchanged until
2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 8 – 60691  CEI:2002
INTRODUCTION
Les protecteurs thermiques, définis comme des dispositifs n'étant pas réutilisables, fonction-
nant une seule fois sans réutilisation, sont très employés pour la protection thermique des
appareils dans lesquels, lors de fonctionnements anormaux, une ou plusieurs parties peuvent
atteindre des températures excessives.
Puisque ces dispositifs possèdent plusieurs points communs avec les fusibles miniatures et
qu'ils sont utilisés pour obtenir un niveau de protection comparable, l'effort s'est orienté, dans
cette norme, de façon à établir une série de spécifications principales pour de tels composants.

60691  IEC:2002 – 9 –
INTRODUCTION
Thermal-links, defined as non-resettable devices functioning once only without refunctioning,
are widely applied for the thermal protection of equipment in which, under fault conditions,
one or more parts may reach hazardous temperatures.
As these devices have several aspects in common with miniature fuse-links and are used for
obtaining a comparable degree of protection, this standard has endeavoured to lay down a
number of basic requirements for such devices.

– 10 – 60691  CEI:2002
PROTECTEURS THERMIQUES –
PRESCRIPTIONS ET GUIDE D'APPLICATION
1 Domaine d'application et objet
La présente Norme internationale est applicable aux protecteurs thermiques destinés à être
incorporés dans les appareils électriques, le matériel électronique et ses composants,
normalement utilisés à l'intérieur d'un local, afin de les protéger contre les températures
excessives lors de fonctionnement anormal.
NOTE 1 L'appareil peut ne pas être prévu pour produire de la chaleur.
NOTE 2 L'efficacité de la protection contre les températures excessives dépend logiquement de la position et du
mode de montage du protecteur thermique ainsi que du courant qui le traverse.
NOTE 3 L'attention est attirée sur le fait que les lignes de fuite et les distances d'isolement extérieures,
spécifiées dans le Tableau 3, peuvent dans quelques cas être plus petites que celles exigées par les normes de
certains appareils ou équipements. Dans de tels cas, il convient que des moyens supplémentaires soient prévus
lorsqu'un protecteur thermique est monté dans l'équipement de façon à ajuster les lignes de fuite et les distances
d'isolement aux valeurs exigées par la norme de l'équipement concerné.
Cette norme peut s'appliquer aux protecteurs thermiques utilisés dans d'autres conditions que
celles qui sont réunies à l'intérieur d'un local, pourvu que les conditions climatiques ou autres
de l'entourage immédiat de tels protecteurs thermiques soient comparables à celles de la
présente norme.
Cette norme peut s'appliquer aux protecteurs thermiques dans leurs formes les plus simples
(par exemple les lames ou les fils de fusion), pourvu que le matériau fondu, expulsé pendant
le fonctionnement, ne soit pas préjudiciable à la sécurité du matériel, particulièrement dans le
cas du matériel tenu à la main, ou mobile indépendamment de sa position.
Cette norme est applicable aux protecteurs thermiques dont la tension assignée n'excède pas
690 V en courant alternatif ou en courant continu, et dont le courant assigné n'excède
pas 63 A.
La présente norme est destinée
a) à établir des prescriptions uniformes pour les protecteurs thermiques,
b) à définir des méthodes d'essai,
c) à fournir des renseignements utiles pour l'utilisation des protecteurs thermiques dans les
appareils.
Cette norme n'est pas applicable aux protecteurs thermiques utilisés dans des conditions
extrêmes, telles que des atmosphères corrosives ou explosives.
Cette norme n'est pas applicable aux protecteurs thermiques destinés à être utilisés en
courant alternatif avec une fréquence inférieure à 45 Hz ou supérieure à 62 Hz.

60691  IEC:2002 – 11 –
THERMAL-LINKS –
REQUIREMENTS AND APPLICATION GUIDE
1 Scope and object
This International Standard is applicable to thermal-links intended for incorporation in
electrical appliances, electronic equipment and component parts thereof, normally intended
for use indoors, in order to protect them against excessive temperatures under abnormal
conditions.
NOTE 1 The equipment need not be designed to generate heat.
NOTE 2 The effectiveness of the protection against excessive temperatures logically depends upon the position
and method of mounting of the thermal-link, as well as upon the current which it is carrying.
NOTE 3 Attention is drawn to the fact that the external creepage distances and clearances specified in Table 3
may in some cases be smaller than those required by certain appliance or equipment standards. In such cases,
additional means should be provided when a thermal-link is mounted in the equipment in order to adjust the
creepage distances and clearances to the values required by the relevant equipment standard.
This standard may be applicable to thermal-links for use under conditions other than indoors,
provided that the climatic and other circumstances in the immediate surroundings of such
thermal-links are comparable with those in this standard.
This standard may be applicable to thermal-links in their simplest forms (e.g. melting strips or
wires), provided that molten materials expelled during function cannot adversely interfere with
the safe use of the equipment, especially in the case of hand-held or portable equipment,
irrespective of its position.
This standard is applicable to thermal-links with a rated voltage not exceeding 690 V a.c. or
d.c. and a rated current not exceeding 63 A.
The object of this standard is
a) to establish uniform requirements for thermal-links,
b) to define methods of test,
c) to provide useful information for the application of thermal-links in equipment.
This standard is not applicable to thermal-links used under extreme conditions such as
corrosive or explosive atmospheres.
This standard is not applicable to thermal-links to be used in circuits on a.c. with a frequency
lower than 45 Hz or higher than 62 Hz.

– 12 – 60691  CEI:2002
2 Références normatives
Les documents de référence suivants sont indispensables pour l'application du présent
document. Pour les références datées, seule l'édition citée s'applique. Pour les références
non datées, la dernière édition du document de référence s'applique (y compris les éventuels
amendements).
CEI 60065:2001, Appareils audio, vidéo et appareils électroniques analogues – Exigences de
sécurité
CEI 60085:1984, Evaluation et classification thermiques de l'isolation électrique
CEI 60112, Méthode pour déterminer des indices de résistance et de tenue au cheminement
des matériaux isolants solides dans des conditions humides
CEI 60216-1:2001, Matériels isolants électriques – Propriétés d'endurance thermique –
Partie 1: Méthodes de vieillissement et évaluation des résultats d'essai
CEI 60664-1:1992, Coordination de l'isolement des matériels dans les systèmes (réseaux) à
basse tension – Partie 1: Principes, prescriptions et essais
CEI 60695-2-11:2000, Essais relatifs aux risques du feu – Partie 2-11: Essais au fil
incandescent/chauffant – Méthode d'essai d'inflammabilité pour produits finis
CEI 60695-10-2:1995, Essais relatifs aux risques du feu – Partie 10-2: Guide et méthodes
d'essai pour la minimalisation des effets de chaleurs anormales sur des produits
électrotechniques impliqués dans des feux – Méthode pour vérifier la résistance à la chaleur
des produits en matériaux non métalliques au moyen de l'essai à bille
CEI 60695-10-3:2002, Essais relatifs aux risques du feu – Partie 10-3: Chaleur anormale –
Essai de déformation par réduction des contraintes de moulage
CEI 60695-11-10:1999, Essais relatifs aux risques du feu – Partie 11-10: Flammes d'essai –
Méthodes d'essai horizontale et verticale à la flamme de 50 W
CEI 60695-11-20:1999, Essais relatifs aux risques du feu – Partie 11-20: Flammes d'essai –
Méthodes d'essai à la flamme de 500 W
CEI 60730-1:1999, Dispositifs de commande électrique automatiques à usage domestique et
analogue – Partie 1: Règles générales
CEI 61210:1993, Dispositifs de connexion – Bornes plates à connexion rapide pour conduc-
teurs électriques en cuivre – Prescriptions de sécurité
UL 1020:1994, Thermal Cutoffs for Use in Electrical Appliances and Components
———————
Une quatrième édition de la CEI 60112, prévue pour 2003, est en préparation.

60691  IEC:2002 – 13 –
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60065:2001, Audio, video and similar electronic apparatus – Safety requirements
IEC 60085:1984, Thermal evaluation and classification of electrical insulation
IEC 60112, Method for determining the comparative and the proof tracking indices of solid
insulating materials under moist conditions
IEC 60216-1:2001, Electrical insulating materials – Properties of thermal endurance – Part 1:
Ageing procedures and evaluation of test results
IEC 60664-1:1992, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60695-2-11:2000, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products
IEC 60695-10-2:1995, Fire hazard testing – Part 10-2: Guidance and test methods for the
minimization of the effects of abnormal heat on electrotechnical products involved in fires –
Method for testing products made from non-metallic materials for resistance to heat using the
ball pressure test
IEC 60695-10-3:2002, Fire hazard testing – Part 10-3: Abnormal heat – Mould stress relief
distortion test
IEC 60695-11-10:1999, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and
vertical flame test methods
IEC 60695-11-20:1999, Fire hazard testing – Part 11-20: Test flames – 500 W flame test
methods
IEC 60730-1:1999, Automatic electrical controls for household and similar use – Part 1:
General requirements
IEC 61210:1993, Connecting devices – Flat quick-connect terminations for electrical copper
conductors – Safety requirements
UL 1020:1994, Thermal Cutoffs for Use in Electrical Appliances and Components
———————
A fourth edition of IEC 60112, due to be published in 2003, is being prepared.

– 14 – 60691  CEI:2002
3 Définitions
Pour les besoins de la présente norme internationale, les définitions suivantes s’appliquent.
3.1
distance d'isolement
distance la plus courte dans l'air entre deux parties conductrices
3.2
ligne de fuite
distance la plus courte le long de la surface d'une matière isolante entre deux parties
conductrices
3.3
température de maintien, T
h
température maximale du protecteur thermique pour laquelle, dans des conditions
déterminées et pendant un temps spécifié, l'état de conductibilité ne changera pas
3.4
série homogène (de protecteurs thermiques)
série de protecteurs thermiques, de dimensions hors-tout communes, dont chacun ne diffère
de l'autre que par des caractéristiques telles que, pour un essai donné, l'essai d'un ou d'un
nombre réduit de protecteurs thermiques déterminés de la série peut être considéré comme
représentatif de tous les protecteurs thermiques de la série
3.5
courant de coupure, l
b
valeur du courant que le protecteur thermique est capable de couper, sous tension assignée
et suivant des caractéristiques spécifiées du circuit
3.6
température limite maximale, T
m
température du protecteur thermique, indiquée par le constructeur, jusqu'à laquelle les
propriétés mécaniques et électriques du protecteur thermique, qui a changé son état de
conductibilité, ne sont pas altérées pendant un temps donné
3.7
pilote de service
classe de fonctionnement dans laquelle la charge électrique finale est commandée par un
appareil auxiliaire tel qu’un relais ou un contacteur
3.8
matériel mobile
matériel qui est déplacé pendant son fonctionnement ou qui peut être facilement déplacé tout
en restant relié au circuit d'alimentation
3.9
courant assigné, I
r
courant utilisé pour la classification du protecteur thermique
3.10
température assignée de fonctionnement, T
f
température de protecteur thermique qui provoque son changement de conductibilité, avec
détection de courant jusqu’à 10 mA comme seule charge

60691  IEC:2002 – 15 –
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1
clearance
shortest distance in air between two conductive parts
3.2
creepage distance
shortest distance along the surface of insulating material between two conductive parts
3.3
holding temperature, T
h
maximum temperature of the thermal-link at which it will not change its state of conductivity
during a specified time under specified conditions
3.4
homogeneous series (of thermal-links)
series of thermal-links having common overall construction, deviating from each other only in
such characteristics that, for a given test, the testing of one or a reduced number of particular
thermal-links of that series shall be taken as representative for all the thermal-links of the
series
3.5
interrupting current, l
b
value of the current that the thermal-link is capable of interrupting at rated voltage and under
specified circuit conditions
3.6
maximum temperature limit, T
m
temperature of the thermal-link stated by the manufacturer, up to which the mechanical and
electrical properties of the thermal-link, having changed its state of conductivity, will not be
impaired for a given time
3.7
pilot duty
class of operation in which the ultimate electrical load is controlled by an auxiliary means
such as a relay or contactor
3.8
portable equipment
equipment which is moved while in operation or which can easily be moved from one place to
another while connected to the supply
3.9
rated current, I
r
current used to classify a thermal-link
3.10
rated functioning temperature, T
f
temperature of the thermal-link which causes it to change its state of conductivity with a
detection current up to 10 mA as the only load

– 16 – 60691  CEI:2002
3.11
tension assignée, U
r
tension qui sert à la classification du protecteur thermique
3.12
élément thermique
matériau métallique ou non métallique faisant partie du protecteur thermique et sensible à la
température par un changement d’état tel que solide à liquide à la température pour laquelle il
a été calibré
3.13
protecteur thermique
élément non réutilisable, incorporant un élément thermique, qui ouvrira un circuit une seule
fois lorsqu'il sera exposé, pendant une durée suffisamment longue, à une température
excédant celle pour laquelle il a été conçu
3.14
surcharge en courant pulsé, lp
train d'impulsions de courant continu que le protecteur thermique est capable de supporter
sans que ses caractéristiques en soient altérées
3.15
essai de type
essai de conformité sur la base d'un ou de plusieurs spécimens d'un produit représentatifs de
la production
3.16
tenue de température étendue, T
h-100
température maximale qu’un protecteur thermique peut tolérer pendant une durée de 100
semaines lorsqu’il supporte la charge du courant assigné à la tension assignée, sans
provoquer l’ouverture du circuit conformément à l’évaluation de la tenue de température
étendue (voir l’Annexe D)
NOTE C’est une caractéristique assignée à considérer par l’utilisateur pendant l’étude du produit final.
3.17
essai de vieillissement après exposition à la chaleur conductrice
CHAT
essai pour évaluer l’aptitude d’un protecteur thermique à fonctionner dans une application
(voir l’Annexe C)
NOTE S’il fonctionne de façon satisfaisante, le protecteur thermique recevra une caractéristique assignée
(CHAT). Cette caractéristique assignée est à considérer par l’utilisateur pour le produit final pendant l’étude de fin
d’utilisation du produit.
4 Prescriptions générales
Une protection convenable de l'équipement contre des températures excessives ne dépend
pas seulement des propriétés du protecteur thermique mais aussi, en grande partie, du
montage du protecteur thermique dans l'équipement. Donc, en plus d'une bonne conception,
les prescriptions du guide d'application de l'Annexe A doivent être prises en compte.
Les protecteurs thermiques doivent avoir des propriétés électriques et mécaniques
convenables, et doivent être construits pour supporter toutes les conditions de manipulations
qu'ils rencontreront probablement durant le montage et l'emploi normal, lorsqu'ils sont utilisés
dans les limites de cette norme.

60691  IEC:2002 – 17 –
3.11
rated voltage, U
r
voltage used to classify a thermal-link
3.12
thermal element
metallic or non-metallic fusible material that is part of a thermal-link and is responsive to
temperature by a change of state such as from solid to liquid at the temperature for which it is
calibrated
3.13
thermal-link
non-resettable device incorporating a thermal element, which will open a circuit once only
when exposed for a sufficient length of time to a temperature in excess of that for which it has
been designed
3.14
transient overload current, l
p
direct current pulse train which the thermal-link is able to withstand without impairing its
characteristics
3.15
type test
conformity testing on the basis of one or more specimens of a product representative of the
production
3.16
extended holding temperature, T
h-100
maximum temperature at which a thermal-link can be maintained while conducting the rated
load current at the rated voltage for a period of 100 weeks which will not cause the thermal-
link to open circuit in accordance with extended holding temperature evaluation (see
Annex D)
NOTE This is a rating for user consideration during the investigation of the end product.
3.17
conductive heat ageing test
CHAT
test to evaluate a thermal-link for use in an appliance (see Annex C)
NOTE If it performs satisfactorily, the thermal-link will be assigned a CHAT rating. This rating is for end-product
user consideration during the investigation of the end-use product.
4 General requirements
Adequate protection of the equipment against excessive temperatures not only depends upon
the properties of the thermal-link but also to a large extent upon the mounting of the thermal-
link in the equipment. Therefore, in addition to good engineering practice, the requirements of
the application guide in Annex A shall be considered.
Thermal-links shall have adequate electrical and mechanical strength and shall be
constructed so as to withstand all conditions of handling likely to be encountered during
mounting and normal use, when used within the requirements of this standard.

– 18 – 60691  CEI:2002
Lorsqu'un protecteur thermique change son état de conductibilité, ni arc ni flamme ne doivent
être entretenus et aucun matériau qui pourrait provoquer des dommages à son entourage
immédiat ou provoquer un risque de choc électrique ou de feu ne doit être expulsé.
NOTE Pour l'emploi de protecteurs thermiques sous forme de lames ou de fils de fusion, il convient de veiller à
ce que le métal fondu ne court-circuite ni ne réduise les lignes de fuite et distances d'isolement, pour réduire les
risques d’endommagement du système d’isolation du matériel.
Après son fonctionnement, le protecteur thermique ne doit pas avoir subi de dommages,
quand il est soumis à des températures ne dépassant pas T , tels que la sécurité du matériel
m
en ce qui concerne les risques de chocs électriques ou de claquages électriques soit
compromise.
5 Conditions générales d'essais
Sauf indication contraire, tous les essais décrits dans la présente norme sont des essais de
type et doivent être effectués dans les conditions ambiantes.
Si le résultat d'un essai dépend de façon appréciable de la position ou du mode de montage
du spécimen, la condition la plus défavorable doit être retenue pour les essais en question et
notée.
Si un protecteur thermique a été spécialement conçu pour être utilisé dans un type précis de
matériel, et ne peut pas être essayé séparément, les essais de la présente norme doivent
être conduits dans ce matériel ou dans la partie correspondante ou similaire.
Dans le cas de vérification d'une série homogène de protecteurs thermiques, tous les essais
doivent être réalisés sur les protecteurs thermiques avec T la plus basse et la plus élevée.
f
Les protecteurs thermiques ayant des températures de fonctionnement intermédiaires ne
seront soumis qu'aux essais de 10.6, 11.2, 11.3 et 11.4.
Le nombre total de spécimens nécessaires est de 48. Quinze spécimens, sur un total de 48,
sont conservés dans l'éventualité d'une répétition de certains essais. Trente-trois spécimens,
sur un total de 48, sont divisés en groupes auxquels sont assignées des lettres alphabétiques
de A à K. Chaque groupe comprend trois spécimens. En général, les essais doivent être réa-
lisés dans l'ordre indiqué au Tableau 1 mais, sur demande, certains essais peuvent être
répétés, par exemple l'essai sur le marquage (voir l’Article 7). Des échantillons supplé-
mentaires peuvent être nécessaires conformément à la note 3 du Tableau 1.
Aucun défaut n'est accepté dans les essais effectués conformément aux Articles 10 et 11.
Si, dans l'un des essais effectués conformément aux autres Articles, un défaut est constaté,
cet essai doit être répété sur le double de spécimens et aucun autre défaut ne doit être toléré.
L’essai de vieillissement après exposition à la chaleur conductrice est applicable quand cela
est indiqué par le constructeur. Cet essai doit être effectué sur des protecteurs thermiques de
température assignée de fonctionnement (T ) de 175 °C ou au-dessus. L’essai de vieillisse-
f
ment après exposition à la chaleur conductrice est facultatif pour les protecteurs thermiques
de température assignée de fonctionnement (T ) inférieure à 175 °C.
f
Exception: L’essai de vieillissement après exposition à la chaleur conductrice peut être omis
si le protecteur thermique est de type eutectique et est fabriqué sans contacts.
NOTE Aux Etats-Unis, l’essai de vieillissement après exposition à la chaleur conductrice doit être déclaré.

60691  IEC:2002 – 19 –
When a thermal-link changes its state of conductivity, no arc or flame shall be maintained, nor
material expelled that might impair the surrounding area or otherwise create a risk of electric
shock or fire.
NOTE For thermal-links using melting strips or wires, care should be taken to prevent molten material from short-
circuiting or bridging creepage distances and clearances in air, so as to reduce the risk of impairing the insulation
system of the equipment.
After it has functioned, the thermal-link shall not be damaged when subjected to temperatures
not exceeding T , in such a way that the safety of the equipment with regard to risk of electric
m
shock hazard and electrical breakdown is impaired.
5 General notes on tests
Unless otherwise indicated, all tests described in this standard are type tests and shall be
carried out under room ambient conditions.
If the result of a test is influenced, to an appreciable extent, by the position and method of
mounting of the specimen, the most unfavourable condition shall be chosen for the relevant
tests and recorded.
If a thermal-link has been spec
...

IEC 60691 ®
Edition 3.2 2010-02
CONSOLIDATED
VERSION
VERSION
CONSOLIDÉE
colour
inside
Thermal-links – Requirements and application guide

Protecteurs thermiques – Prescriptions et guide d'application

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IEC 60691 ®
Edition 3.2 2010-02
CONSOLIDATED
VERSION
VERSION
CONSOLIDÉE
colour
inside
Thermal-links – Requirements and application guide

Protecteurs thermiques – Prescriptions et guide d'application

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.50 ISBN 978-2-8322-2203-4

IEC 60691 ®
Edition 3.2 2010-02
REDLINE VERSION
VERSION REDLINE
colour
inside
Thermal-links – Requirements and application guide

Protecteurs thermiques – Prescriptions et guide d'application

– 2 – IEC 60691:2002
+AMD1:2006+AMD2:2010 CSV  IEC 2010
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope and object . 6
2 Normative references . 6
3 Definitions . 7
4 General requirements . 9
5 General notes on tests . 9
6 Classification . 13
7 Marking . 13
8 Documentation . 14
9 Mechanical requirements . 14
10 Electrical requirements . 18
11 Temperature tests . 25
12 Resistance to rusting . 27
13 Manufacturer’s validation programme . 27

Annex A (normative) Application guide . 28
Annex B (normative) Alternative ageing test for thermal-links with T greater than
h
250 °C for use in electric irons . 29
Annex C (normative) Conductive heat ageing test . 30
Annex D (informative) Extended holding temperature evaluation . 34
Annex E (normative) Seal ageing test . 36
Annex F (normative) Identification requirements . 38
Annex G (informative) Indelibility of markings . 39

Figure 1 – Bending/twist test . 17
Figure C.1 – Typical test fixture assembly . 32
Figure C.2 – Typical thermal-link test oven . 33
Figure D.1 – Typical terminal block support test fixture . 35
Figure E.1 – Conditioning time versus oven temperature for proposed temperature index . 37
Figure G.1 – Apparatus for testing durability of markings . 39

Table 1 – Test schedule . 12
Table 2 – Strength of terminals – Minimum required tensile and thrust test forces . 18
Table 3 – Creepage distances and clearances (absolute minimum values) . 19
Table 4 – Test voltages for dielectric strength . 20
Table 5 – Test current for interrupting test . 22
Table 6 – Limited short-circuit test capacity . 24

+AMD1:2006+AMD2:2010 CSV  IEC 2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
THERMAL-LINKS –
REQUIREMENTS AND APPLICATION GUIDE

FOREWORD
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This Consolidated version of IEC 60691 bears the edition number 3.2. It consists of the
third edition (2002-12) [documents 32C/321/FDIS and 32C/329/RVD], its amendment 1
(2006-09) [documents 32C/395/FDIS and 32C/400/RVD] and its amendment 2 (2010-02)
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In this Redline version, a vertical line in the margin shows where the technical content
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This publication has been prepared for user convenience.

– 4 – IEC 60691:2002
+AMD1:2006+AMD2:2010 CSV  IEC 2010
International Standard IEC 60691 has been prepared by subcommittee 32C: Miniature fuses,
of IEC technical committee 32: Fuses.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The basis for this standard is the harmonization of the US national standard UL 1020, fifth
edition (withdrawn 2003), which deals with thermal cutoffs/thermal-links, has served as a
basis for the elaboration of this new edition and IEC 60691, second edition, together with its
amendments 1 and 2.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication 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 correct understanding
of its contents. Users should therefore print this publication using a colour printer.

+AMD1:2006+AMD2:2010 CSV  IEC 2010
INTRODUCTION
Thermal-links, defined as non-resettable devices functioning once only without refunctioning,
are widely applied for the thermal protection of equipment in which, under fault conditions,
one or more parts may reach hazardous temperatures.
As these devices have several aspects in common with miniature fuse-links and are used for
obtaining a comparable degree of protection, this standard has endeavoured to lay down a
number of basic requirements for such devices.

– 6 – IEC 60691:2002
+AMD1:2006+AMD2:2010 CSV  IEC 2010
THERMAL-LINKS –
REQUIREMENTS AND APPLICATION GUIDE

1 Scope and object
This International Standard is applicable to thermal-links intended for incorporation in
electrical appliances, electronic equipment and component parts thereof, normally intended
for use indoors, in order to protect them against excessive temperatures under abnormal
conditions.
NOTE 1 The equipment need not be designed to generate heat.
NOTE 2 The effectiveness of the protection against excessive temperatures logically depends upon the position
and method of mounting of the thermal-link, as well as upon the current which it is carrying.
NOTE 3 Attention is drawn to the fact that the external creepage distances and clearances specified in Table 3
may in some cases be smaller than those required by certain appliance or equipment standards. In such cases,
additional means should be provided when a thermal-link is mounted in the equipment in order to adjust the
creepage distances and clearances to the values required by the relevant equipment standard.
This standard may be applicable to thermal-links for use under conditions other than indoors,
provided that the climatic and other circumstances in the immediate surroundings of such
thermal-links are comparable with those in this standard.
This standard may be applicable to thermal-links in their simplest forms (e.g. melting strips or
wires), provided that molten materials expelled during function cannot adversely interfere with
the safe use of the equipment, especially in the case of hand-held or portable equipment,
irrespective of its position.
This standard is applicable to thermal-links with a rated voltage not exceeding 690 V a.c. or
d.c. and a rated current not exceeding 63 A.
The object of this standard is
a) to establish uniform requirements for thermal-links,
b) to define methods of test,
c) to provide useful information for the application of thermal-links in equipment.
This standard is not applicable to thermal-links used under extreme conditions such as
corrosive or explosive atmospheres.
This standard is not applicable to thermal-links to be used in circuits on a.c. with a frequency
lower than 45 Hz or higher than 62 Hz.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60065:2001, Audio, video and similar electronic apparatus – Safety requirements
Amendment 1 (2005)
IEC 60085:1984 2004, Thermal evaluation and classification of Electrical insulation – Thermal
classification
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IEC 60112:2003, Method for determining the comparative and the proof tracking indices of
solid insulating materials under moist conditions Method for the determination of the proof
and the comparative tracking indices of solid insulating materials
IEC 60216-1:2001, Electrical insulating materials – Properties of thermal endurance – Part 1:
Ageing procedures and evaluation of test results
IEC 60664-1:1992, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
Amendment 1 (2000)
Amendment 2 (2002)
IEC 60695-2-11:2000, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products
IEC 60695-10-2:1995 2003, Fire hazard testing – Part 10-2: Guidance and test methods for
the minimization of the effects of abnormal heat on electrotechnical products involved in fires
– Method for testing products made from non-metallic materials for resistance to heat using
the ball pressure test Abnormal heat – Ball pressure test
IEC 60695-10-3:2002, Fire hazard testing – Part 10-3: Abnormal heat – Mould stress relief
distortion test
IEC 60695-11-10:1999, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and
vertical flame test methods
Amendment 1 (2003)
IEC 60695-11-20:1999, Fire hazard testing – Part 11-20: Test flames – 500 W flame test
methods
IEC 60730-1:1999, Automatic electrical controls for household and similar use – Part 1:
General requirements
Amendment 1 (2003)
IEC 61210:1993, Connecting devices – Flat quick-connect terminations for electrical copper
conductors – Safety requirements
UL 1020:1994, Thermal Cutoffs for Use in Electrical Appliances and Components
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1
clearance
shortest distance in air between two conductive parts
3.2
creepage distance
shortest distance along the surface of insulating material between two conductive parts
———————
A fourth edition of IEC 60112, due to be published in 2003, is being prepared.

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3.3
holding temperature, T
h
maximum temperature of the thermal-link at which it will not change its state of conductivity
during a specified time under specified conditions
3.4
homogeneous series (of thermal-links)
series of thermal-links having common overall construction, deviating from each other only in
such characteristics that, for a given test, the testing of one or a reduced number of particular
thermal-links of that series shall be taken as representative for all the thermal-links of the
series
3.5
interrupting current, l
b
value of the current that the thermal-link is capable of interrupting at rated voltage and under
specified circuit conditions
3.6
maximum temperature limit, T
m
temperature of the thermal-link stated by the manufacturer, up to which the mechanical and
electrical properties of the thermal-link, having changed its state of conductivity, will not be
impaired for a given time
3.7
pilot duty
class of operation in which the ultimate electrical load is controlled by an auxiliary means
such as a relay or contactor
rating assigned to a switching device that controls the coil of another electro-mechanical
device such as a solenoid, relay or contactor
3.8
portable equipment
equipment which is moved while in operation or which can easily be moved from one place to
another while connected to the supply
3.9
rated current, I
r
current used to classify a thermal-link
3.10
rated functioning temperature, T
f
temperature of the thermal-link which causes it to change its state of conductivity with a
detection current up to 10 mA as the only load
3.11
rated voltage, U
r
voltage used to classify a thermal-link
3.12
thermal element
metallic or non-metallic fusible material that is part of a thermal-link and is responsive to
temperature by a change of state such as from solid to liquid at the temperature for which it is
calibrated
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3.13
thermal-link
non-resettable device incorporating a thermal element, which will open a circuit once only
when exposed for a sufficient length of time to a temperature in excess of that for which it has
been designed
3.14
transient overload current, l
p
direct current pulse train which the thermal-link is able to withstand without impairing its
characteristics
3.15
type test
conformity testing on the basis of one or more specimens of a product representative of the
production
3.16
extended holding temperature, T
h-100
maximum temperature at which a thermal-link can be maintained while conducting the rated
load current at the rated voltage for a period of 100 weeks which will not cause the thermal-
link to open circuit in accordance with extended holding temperature evaluation (see
Annex D)
NOTE This is a rating for user consideration during the investigation of the end product.
3.17
conductive heat ageing test
CHAT
test to evaluate a thermal-link for use in an appliance (see Annex C)
NOTE If it performs satisfactorily, the thermal-link will be assigned a CHAT rating. This rating is for end-product
user consideration during the investigation of the end-use product.
4 General requirements
Adequate protection of the equipment against excessive temperatures not only depends upon
the properties of the thermal-link but also to a large extent upon the mounting of the thermal-
link in the equipment. Therefore, in addition to good engineering practice, the requirements of
the application guide in Annex A shall be considered.
Thermal-links shall have adequate electrical and mechanical strength and shall be
constructed so as to withstand all conditions of handling likely to be encountered during
mounting and normal use, when used within the requirements of this standard.
When a thermal-link changes its state of conductivity, no arc or flame shall be maintained, nor
material expelled that might impair the surrounding area or otherwise create a risk of electric
shock or fire.
NOTE For thermal-links using melting strips or wires, care should be taken to prevent molten material from short-
circuiting or bridging creepage distances and clearances in air, so as to reduce the risk of impairing the insulation
system of the equipment.
After it has functioned, the thermal-link shall not be damaged when subjected to temperatures
not exceeding T , in such a way that the safety of the equipment with regard to risk of electric
m
shock hazard and electrical breakdown is impaired.
5 General notes on tests
Unless otherwise indicated, all tests described in this standard are type tests and shall be
carried out under room ambient conditions.

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Unless otherwise specified, only tests that are not required to be performed inside an
environmental chamber and/or test oven shall be carried out under the following atmospheric
conditions:
Temperature: 15 °C to 35 °C
Relative humidity: 25 % to 75 %
4 5
Air pressure: 8,6 × 10 Pa to 1,06 × 10 Pa
NOTE 1 The required atmospheric conditions during testing can be controlled when carrying out the tests and
during the duration of the tests. The required atmospheric conditions do not have to be maintained in a test
laboratory when tests are not performed.
Where the above-mentioned conditions have a significant influence, they shall be kept
substantially constant during the tests.
If the temperature limits given in this clause are too wide for certain tests, these shall be
repeated, in case of doubt, at a temperature of (23 ± 1) °C.
In every test report, the ambient temperature shall be stated. If the standard conditions for
relative humidity or pressure are not fulfilled during the tests, a note to this affect shall be
added to the report.
If the result of a test is influenced, to an appreciable extent, by the position and method of
mounting of the specimen, the most unfavourable condition shall be chosen for the relevant
tests and recorded.
If a thermal-link has been specifically designed for use in a special type of equipment and
cannot be tested separately, the tests of this standard shall be performed in that equipment or
in the relevant part of it, or similar.
When testing a homogeneous series of thermal-links, all the tests shall be applied to thermal-
links with the lowest and highest T . Thermal-links with intermediate rated functioning tem-
f
peratures need only be subjected to tests according to 10.6, 11.2, 11.3 and 11.4.
The total number of specimens required is 48 45. Out of a total of 48 45 specimens, 15 are
kept as spares in case some of the tests have to be repeated. Out of a total of 48 45
specimens, 33 30 are divided into groups assigned an alphabetical letter from A to K J. Each
group consists of three specimens. In general, tests shall be performed in the order indicated
in Table 1 but, if so required, tests may be repeated, for example the test on marking (see
Clause 7). Additional samples may be needed according to Note 3 2 of Table 1.
No failures are permitted in the tests carried out in accordance with Clauses 10 and 11.
NOTE 2 For optional tests, additional samples will be required per the annexes.
If, in any of the tests carried out in accordance with the other any clauses, one a failure is
reported, that test shall be repeated on twice the number of specimens and no further failures
are allowed the cause of the failure will be identified and corrective action taken. Based on
the failure analysis report and the corrective action, at a minimum, that test sequence shall be
repeated on twice the number of revised specimens and no further failures are allowed.
The conductive heat ageing test of Annex C is applicable when declared by the manufacturer.
This test shall be conducted on thermal-links with a functioning temperature (T ) rating of
f
175 °C or above. The conductive heat ageing test is optional for thermal-links with a T rating
f
less than 175 °C.
Exception: The conductive heat ageing test may be omitted if the thermal-link is of eutectic
type and is constructed without contacts.
NOTE 3 In the USA the conductive heat ageing test is required to be declared.

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Manufacturer's inspection and factory test programme
The manufacturer shall provide regular production control, inspection and tests. Details of the
programme shall be agreed to between manufacturer and the testing house.

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Table 1 – Test schedule
Specimen groups
Clause or
Test
subclause
A B C D E F G H I J K
7* Marking (rub test) X X
9 Mechanical requirements
9.2* Tensile force X
9.3* Thrust force X
9.4* Bending/twist force  X
12* Resistance to rusting (ferrous parts only)   X
10 Electrical requirements
10.1* Creepage distances and clearances   X X X
10.2.1* Humidity test X X X  X X
10.2.2* Temperature and humidity cycle conditioning X X X  X X X
(note 2)
12* Resistance to rusting (ferrous parts only) X X X
10.3* Dielectric strength (if applicable) X X X  X X X
10.4* Insulation resistance (if applicable) X X X  X X X
10.5* Resistance to tracking  X X
10.6 Interrupting current   X X X
10.7* Transient overload current X X   X X
11 Temperature tests
11.2 Check on T X X
f
11.3 Check on T followed by dielectric test and  X X
m
insulation resistance
11.4 Ageing X  X X X X X X
step 1 (optional) 21 days
step 2 (mandatory) 21 days
step 3 (mandatory) 14 days
step 4 (mandatory) 7 days
step 5 (mandatory) 7 days
step 6 (mandatory) 24 h
10.3 Dielectric strength X X X X X X X X X X X
10.4 Insulation resistance X X X X X X X X X X X
7* Marking (visual inspection only) X X
NOTE 1 For homogeneous series, tests marked with an asterisk may be omitted for intermediate ratings.
NOTE 2 At the manufacturer's request, the humidity test of 10.2.1 can be omitted if the third humidity cycle of the
temperature and humidity condition of 10.2.2 is conducted for 168 h.
NOTE 3 2 If the conditions of voltage, power and current in c), d) and e) of 10.6.2 are not covered by one test, a
minimum of three samples should be tested for each condition.

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6 Classification
6.1 Electrical conditions
With regard to electrical conditions, the following terms are used:
a) Voltage
1) AC
2) DC
b) Current
1) Resistive
2) Inductive
– Motor
– Pilot duty
– Electric discharge lamp
6.2 Thermal conditions
With regard to thermal conditions, the following symbols and abbreviations are used:
a) T
f
b) T
h
c) T
m
d) CHAT
e) T
h-100
6.3 Resistance to tracking
With regard to resistance to tracking, the following ranges are used:
a) Proof tracking index from 120 to 174;
b) Proof tracking index from 175 to 249;
c) Proof tracking index greater than or equal to 250.
NOTE These ranges are based on test methods for surface tracking laid down in IEC 60112.
7 Marking
Each thermal-link shall be marked with the following:
a) type or catalogue reference;
b) manufacturer’s name or trade mark;
c) rated functioning temperature T with or without the symbol T followed by the number of
f f
degrees Celsius (marked with °C or C);
d) date code which identifies the date of manufacture and which does not repeat for at least
10 years, and a factory location or code, stamped on the thermal-link or the smallest
packaging.
NOTE 1 If there is only one factory, the factory location may be omitted.

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The rated functioning temperature T may be omitted if a different type or catalogue reference
f
is employed for each different functioning temperature.
Where size permits, additional markings such as rated voltage followed by V, rated current
followed by A, and other optional markings as needed, may be placed on the thermal-link.
Marking shall be indelible and legible.
Indelibility is checked by trying to remove the marking by rubbing lightly for 15 s with a piece
of cloth soaked with water. Legibility is checked by inspection. After the ageing tests of 11.4,
compliance is checked by inspection.
NOTE 2 Instead of “rubbing lightly” the apparatus shown in Figure G.1 may be used.
If the thermal-link is small in size, and not intended to be replaced, the markings in
accordance with a), b), c) and d) above shall be printed on the packaging, together with a
reference to this standard.
Compliance is checked by inspection.
8 Documentation
The manufacturer shall provide in his technical documentation, catalogues or instructional
leaflets the following information in addition to that required in Clause 7:
a) classification in accordance with Clause 6;
b) for each of the classifications
1) characteristic temperatures T , T , T ;
f h m
2) characteristic currents l , l , l ;
r b p
3) rated voltage U ;
r
c) suitability for sealing in, or use with impregnating fluids or cleaning solvents;
NOTE 1 In order to avoid possible damage to the thermal-link, the manufacturer should be consulted when
the end-use application involves sealing in or the use of cleaning solvents.
d) information for mounting the thermal-link in the equipment.
NOTE 2 For reasons of safety, it should be made clear in the documentation that a thermal-link is a non-
repairable item and that, in case of replacement, an equivalent thermal-link from the same manufacturer and
having the same catalogue reference should be used, mounted in exactly the same way.
NOTE 3 Catalogue or reference numbers should define those parameters such as temperature, current and
voltage which together classify a thermal-link.
e) thermal-links small in size and not intended to be replaced.
NOTE 1 In order to avoid possible damage to the thermal-link, the manufacturer should be consulted when
the end-use application involves sealing in or the use of cleaning solvents.
NOTE 2 For reasons of safety, it should be made clear in the documentation that a thermal-link is a non-
repairable item and that, in case of replacement, an equivalent thermal-link from the same manufacturer and
having the same catalogue reference should be used, mounted in exactly the same way.
NOTE 3 Catalogue or reference numbers should define those parameters such as temperature, current and
voltage, which together classify a thermal-link.
9 Mechanical requirements
Thermal-links shall have adequate mechanical strength and stability so as to withstand the
stresses likely to be encountered during handling, normal use and fault conditions of the
relevant end-use equipment.
Tab terminals shall be constructed in accordance with IEC 61210.

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Current-carrying parts shall be constructed in such a way that contact pressure is not
transmitted through non-metallic material other than ceramic, or any material considered as
having sufficient dimensional stability over the range of temperatures to be expected, unless
there is sufficient resilience in the corresponding metal parts to compensate for any shrinkage
or distortion of the non-metallic material.
Current-carrying parts shall have the necessary mechanical strength, be capable of carrying
the rated current and shall be of a material that is acceptable for the particular application.
For current-carrying parts, temperature limits should be considered according to Table 14.1 of
IEC 60730-1.
Friction shall not be used to secure uninsulated live parts (including terminals) to supporting
surfaces if there is a risk of such parts turning or shifting their position, resulting in the
reduction of spacings to less than those required elsewhere in this standard. The security of
contact assemblies shall be such that alignment of contacts is maintained.
Leads and terminal parts shall be secured so that stress on them during installation and
normal use does not impair operation of the thermal-link. Thermal-links using seals with
formed leads for use in appliances or components shall not be bent less than 3 mm from the
thermal-link seal.
Exception: Leads may be bent less than 3 mm from the seal if
a) the thermal-link manufacturer's bending fixture and procedure does not transmit stress to
the thermal-link operating mechanism, and if
b) formed test samples shall be subjected to the bending/twist lead secureness test of 9.4
and the rated functioning temperature test of 11.2.
Thermal-links with leads smaller than 0,21 mm shall be provided with application instructions
that instruct the user how to mount the device in equipment, taking into consideration the
device's temperature response. The instructions shall also include guidance on the effects
that movement and vibration in the equipment may have on the thermal-link's terminals,
connections and other mounting components.
A terminal for a soldered connection shall have provision, such as a hole, for holding the
conductor independently of solder.
When applicable, provision shall be made for securely mounting a thermal-link in position.
Exception: Types intended to be embedded in windings and the like need not have provision
for mounting.
Bolts, screws, or other parts used for mounting an assembly having a thermal-link shall be
independent of those used for securing component parts of the assembly.
Compliance is checked by the lead secureness tests of 9.1. Mounting and securement
instructions shall be provided with thermal-links for the manufacturer of the end-product in
accordance with Annex A.
9.1 Lead secureness tests
If force applied to thermal-link wire leads causes breakdown of one or more parts leading
directly or indirectly to stress being applied to the operating mechanism, the tests described in
9.2, 9.3 and 9.4 shall be conducted. There shall be no displacement of parts that would tend
to reclose a thermal-link or reduce creepages or clearances as a result of the tests specified

90°
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in 9.2 and 9.3. There shall be no displacement of parts other than the wire leads as a result of
the test specified in 9.4.
The tests shall be conducted with the samples at an ambient temperature of (25 ± 5) °C.
9.2 Tensile test
The thermal-link shall be supported in any convenient manner in order not to damage it
and a tensile force as specified in Table 2 shall be applied to each lead for 10 1 min.
9.3 Thrust test
The thermal-link shall be supported using any convenient means such that it is not damaged
and a thrust force as specified in Table 2 shall be applied to each lead for 10 1 min at
a distance of 2 mm from the thermal-link.
9.4 Bending/twist test
The thermal-link shall be rigidly supported such that it is not damaged. Each lead shall be
bent through 90° at a location 10 mm from the body of the thermal-link and then twisted
through 180° as shown in Figure 1.

Thermal-link
rigidly supported
10 mm
Step 1: Bend
180°
Step 2: Twist
IEC  2769/02
90°
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Thermal-link
rigidly supported
10 mm
Step 1: Bend
180°
Step 2: Twist
IEC  2769/02
Figure 1 – Bending/twist test
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Table 2 – Strength of terminals – Minimum required tensile and thrust test forces
Nominal cross-sectional area of the terminal, A Tensile force Thrust force
mm N N
Up to and including 0,05 1 0,25
Over 0,05 up to and including 1,2 20 × A 5 × A
Over 1,2 40 8
NOTE A is the nominal cross-sectional area of the terminal in mm .
10 Electrical requirements
Thermal-links shall comply with the relevant requirements in this clause with regard to test
voltages, currents, insulation resistances, creepage distances and clearances in air.
Contacts used for the current path in a thermal-link shall withstand the voltage stress
determined by the voltage source in the circuit. Current-carrying elements or contacts,
together with their terminals, are usually isolated from metal parts such as mounting brackets,
metal enclosures and the like, by insulating material.
If mounting brackets or metal parts of the thermal-link's enclosure are accessible or
connected through low impedances to metal enclosures of the equipment accessible to the
user from the outside, the insulation between the current-carrying elements of the thermal-link
and such conductive enclosures shall be adequate under specified conditions of ambient
temperature and humidity.
If it is necessary to investigate an insulating material, the following standards shall be used :
IEC 60085, IEC 60216-1, IEC 60695-2-11, IEC 60695-10-2, IEC 60695-10-3, IEC 60695-11-
10 and IEC 60695-11-20.
Exception: Seals and potting compounds not relied upon for contact alignment or secureness of leads may be
subjected to the seal ageing test specified in Annex E.
NOTE 1 The rated voltage, U , as stated by the manufacturer is used for deriving the relevant values for test
r
voltages.
NOTE 2 The voltage rating of a thermal-link should be based on the source voltage in the circuit. The voltage
rating for the insulation between current-carrying parts of such devices and the enclosure may be increased by
additional insulation; for example, by wrapping the thermal-link in insulating foil.
10.1 Creepage distances and clearances
The creepage distances and clearances between current-carrying parts (contacts together
with their terminals)
...