prEN IEC 60691:2022

Thermal-links - Requirements and application guide

Temperatursicherungen - Anforderungen und Anwendungshinweise

Protecteurs thermiques - Exigences et guide d'application

Termični taljivi vložki - Zahteve in navodilo za uporabo

General Information

• Status: Not Published
• ICS: 29.120.50 - Fuses and other overcurrent protection devices
• Technical Committee: CLC/SR 32C - Miniature fuses
• Drafting Committee: IEC/SC 32C - IEC_SC_32C
• Current Stage: 4020 - Enquiry circulated
• Due Date: 28-Jan-2022
• Completion Date: 28-Jan-2022
• Directive: 2014/35/EU - Directive 2014/35/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of electrical equipment designed for use within certain voltage limits
• Mandate: M/511 - Mandate to CEN, CENELEC and ETSI relating to harmonised standards in the field of the Low Voltage Directive
• Ref Project: oSIST prEN IEC 60691:2022 - Thermal-links - Requirements and application guide

RELATIONS

• Revised: EN 60691:2016 - Thermal-links - Requirements and application guide
• Effective Date: 03-Mar-2020
• Revised: EN 60691:2016/A1:2019 - Thermal-links - Requirements and application guide
• Effective Date: 31-Aug-2021

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN IEC 60691:2022
01-marec-2022
Termični taljivi vložki - Zahteve in navodilo za uporabo
Thermal-links - Requirements and application guide
Temperatursicherungen - Anforderungen und Anwendungshinweise
Protecteurs thermiques - Exigences et guide d'application
Ta slovenski standard je istoveten z: prEN IEC 60691:2022
ICS:
29.120.50 Varovalke in druga Fuses and other overcurrent
nadtokovna zaščita protection devices
oSIST prEN IEC 60691:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN IEC 60691:2022
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oSIST prEN IEC 60691:2022
32C/598/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60691 ED5
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2022-01-28 2022-04-22
SUPERSEDES DOCUMENTS:
32C/579A/CD, 32C/595/CC
IEC SC 32C : MINIATURE FUSES
SECRETARIAT: SECRETARY:
China Mr Jianqiang Zou
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY

SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING

Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.

Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of

which they are aware and to provide supporting documentation.
TITLE:
Thermal-links - Requirements and application guide
PROPOSED STABILITY DATE: 2024
NOTE FROM TC/SC OFFICERS:

The markup of changes indicate the revision compared to the CD document (32C/579A/CD).

Copyright © 2021 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to download this

electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.

You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without

permission in writing from IEC.
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1 CONTENTS

2 FOREWORD ........................................................................................................................... 4

3 INTRODUCTION ..................................................................................................................... 6

4 1 Scope .............................................................................................................................. 7

5 2 Normative references ...................................................................................................... 7

6 3 Terms and definitions ...................................................................................................... 8

7 4 General requirements .................................................................................................... 10

8 5 General notes on tests .................................................................................................. 10

9 6 Classification ................................................................................................................. 12

10 6.1 Electrical conditions .............................................................................................. 12

11 6.2 Thermal conditions ............................................................................................... 13

12 6.3 Resistance to tracking........................................................................................... 13

13 7 Marking ......................................................................................................................... 13

14 8 Documentation .............................................................................................................. 14

15 9 Constructional requirements .......................................................................................... 15

16 9.1 General ................................................................................................................. 15

17 9.2 Lead secureness tests .......................................................................................... 16

18 9.2.1 General ......................................................................................................... 16

19 9.2.2 Tensile test .................................................................................................... 16

20 9.2.3 Thrust test ..................................................................................................... 16

21 9.2.4 Bending/twist test .......................................................................................... 16

22 9.3 Contacts used for the current path ........................................................................ 17

23 9.4 Accessible mounting brackets or metal parts ........................................................ 18

24 9.5 Insulating materials ............................................................................................... 18

25 9.6 Resistance to tracking........................................................................................... 18

26 9.7 Creepage distances and clearances...................................................................... 18

27 9.8 Temperature and humidity cycle conditioning ........................................................ 19

28 9.9 Terminals and terminations ................................................................................... 19

29 10 Electrical requirements .................................................................................................. 20

30 10.1 Dielectric strength ................................................................................................. 20

31 10.2 Insulation resistance ............................................................................................. 20

32 10.3 Interrupting current ............................................................................................... 21

33 10.3.1 General ......................................................................................................... 21

34 10.3.2 Specific conditions ......................................................................................... 21

35 10.4 Transient overload current .................................................................................... 22

36 10.5 Limited short-circuit test ........................................................................................ 23

37 10.5.1 General ......................................................................................................... 23

38 10.5.2 Test method .................................................................................................. 23

39 10.5.3 Fuse size (rating)........................................................................................... 24

40 10.5.4 Compliance ................................................................................................... 24

41 11 Temperature tests ......................................................................................................... 24

42 11.1 General ................................................................................................................. 24

43 11.2 Holding temperature, T ........................................................................................ 25

44 11.3 Rated functioning temperature, T ......................................................................... 25

45 11.4 Maximum temperature limit, T ............................................................................ 25

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46 11.5 Ageing .................................................................................................................. 26

47 12 Resistance to rusting ..................................................................................................... 26

48 13 Manufacturer’s validation programme ............................................................................ 27

49 Annex A (normative) Application guide ................................................................................ 28

50 Annex B (normative) Alternative ageing test for thermal-links with T greater than

51 250 °C for use in electric irons .............................................................................................. 29

52 Annex C (normative) Conductive heat ageing test ................................................................ 30

53 C.1 Conductive heat ageing test .................................................................................. 30

54 C.2 Method ................................................................................................................. 30

55 C.3 Ageing .................................................................................................................. 31

56 C.4 Results ................................................................................................................. 32

57 C.5 Dielectric strength test .......................................................................................... 32

58 C.6 Test oven .............................................................................................................. 32

59 Annex D (informative) Extended holding temperature evaluation .......................................... 34

60 D.1 Extended holding temperature conditioning test .................................................... 34

61 D.2 Load current interrupt test ..................................................................................... 34

62 Annex E (normative) Seal ageing test .................................................................................. 36

63 Annex F (normative) Identification requirements .................................................................. 38

64 Annex G (normative) Indelibility of markings ........................................................................ 39

65 Annex H (normative) Requirements for thermal-link packaged assemblies ........................... 40

66 Bibliography .......................................................................................................................... 45

68 Figure 1 – Bending/twist test ................................................................................................. 17

69 Figure C.1 – Typical test fixture assembly ............................................................................. 32

70 Figure C.2 – Typical thermal-link test oven ........................................................................... 33

71 Figure D.1 – Typical terminal block support test fixture ......................................................... 35

72 Figure E.1 – Conditioning time versus oven temperature for proposed temperature

73 index .................................................................................................................................... 37

74 Figure G.1 – Apparatus for testing durability of markings ...................................................... 39

76 Table 1 – Test schedule ........................................................................................................ 12

77 Table 2 – Strength of leads and terminal parts – Minimum required tensile and thrust

78 test forces ............................................................................................................................. 17

79 Table 3 – Creepage distances and clearances (absolute minimum values) ........................... 19

80 Table 4 – Test voltages for dielectric strength ....................................................................... 20

81 Table 5 – Test current for interrupting test ............................................................................ 21

82 Table 6 – Limited short-circuit test capacity .......................................................................... 23

83 Table H.1 – Push and pull force ............................................................................................ 41

84 Table H.2 – Minimum nominal cross-sectional area of conductor .......................................... 42

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87 INTERNATIONAL ELECTROTECHNICAL COMMISSION
88 ____________
90 THERMAL-LINKS –
91 REQUIREMENTS AND APPLICATION GUIDE
93 FOREWORD

94 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

95 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

96 international co-operation on all questions concerning standardization in the electrical and electronic fields. To

97 this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

98 Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

99 Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

100 in the subject dealt with may participate in this preparatory work. International, governmental and non-

101 governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

102 with the International Organization for Standardization (ISO) in accordance with conditions determined by

103 agreement between the two organizations.

104 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

105 consensus of opinion on the relevant subjects since each technical committee has representation from all

106 interested IEC National Committees.

107 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

108 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

109 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

110 misinterpretation by any end user.

111 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

112 transparently to the maximum extent possible in their national and regional publications. Any divergence

113 between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

114 the latter.

115 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

116 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

117 services carried out by independent certification bodies.

118 6) All users should ensure that they have the latest edition of this publication.

119 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

120 members of its technical committees and IEC National Committees for any personal injury, property damage or

121 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

122 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

123 Publications.

124 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

125 indispensable for the correct application of this publication.

126 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

127 patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

DISCLAIMER

This Consolidated version is not an official IEC Standard and has been prepared for

user convenience. Only the current versions of the standard and its amendment(s)
are to be considered the official documents.

128 This Consolidated version of IEC 60691 bears the edition number 4.1. It consists of the

129 fourth edition (2015-10) [documents 32C/512/FDIS and 32C/515/RVD] and its

130 corrigendum (2016-08), and its amendment 1 (2019-01) [documents 32C/548/FDIS and

131 32C/559/RVD]. The technical content is identical to the base edition and its amendment.

132 In this Redline version, a vertical line in the margin shows where the technical content

133 is modified by amendment 1. Additions are in green text, deletions are in strikethrough

134 red text. A separate Final version with all changes accepted is available in this

135 publication.
136
137
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138 International Standard IEC 60691 has been prepared by subcommittee 32C: Miniature fuses,

139 of IEC technical committee 32: Fuses.
140 This fifth edition constitutes a technical revision.

141 This fifth edition includes the following significant technical changes with respect to the

142 previous edition:
143 a) requirements for thermal-link packaged assemblies;
144 b) renew the requirements and definitions for T -test;

145 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

146 The basis for this standard is the harmonization of the USA national standard, UL 1020, fifth

147 edition (withdrawn 2003), and IEC 60691:1993, together with its Amendment 1:1995 and

148 Amendment 2:2000.

149 The following differing practices of a less permanent nature exist in the country indicated

150 below:
151 – Annex C is required to be declared in the USA;
152 – Annex E is required in the USA, if applicable;
153 – Annex F is required to be declared in the USA.
154 In this standard, the following type is used:
155 – compliance statements: in italic type.

156 The committee has decided that the contents of the base publication and its amendment will

157 remain unchanged until the stability date indicated on the IEC web site under

158 "http://webstore.iec.ch" in the data related to the specific publication. At this date, the

159 publication will be
160 • reconfirmed,
161 • withdrawn,
162 • replaced by a revised edition, or
163 • amended.
164

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 document using a

colour printer.
165
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166 INTRODUCTION

167 Thermal-links, defined as non-resettable devices functioning once only without refunctioning,

168 are widely applied for the thermal protection of equipment in which, under fault (abnormal)

169 conditions, one or more parts may reach hazardous temperatures.

170 As these devices have several aspects in common with miniature fuse-links and are used for

171 obtaining a comparable degree of protection, this standard has endeavoured to lay down a

172 number of basic requirements for such devices.
173
174
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175 THERMAL-LINKS –
176 REQUIREMENTS AND APPLICATION GUIDE
177
178
179
180 1 Scope

181 This International Standard is applicable to thermal-links intended for incorporation in

182 electrical appliances, electronic equipment and component parts thereof, normally intended

183 for use indoors, in order to protect them against excessive temperatures under abnormal

184 conditions.
185 NOTE 1 The equipment is not designed to generate heat.

186 NOTE 2 The effectiveness of the protection against excessive temperatures logically depends upon the position

187 and method of mounting of the thermal-link, as well as upon the current which it is carrying.

188 This standard may be applicable to thermal-links for use under conditions other than indoors,

189 provided that the climatic and other circumstances in the immediate surroundings of such

190 thermal-links are comparable with those in this standard.

191 This standard may be applicable to thermal-links in their simplest forms (e.g. melting strips or

192 wires), provided that molten materials expelled during function cannot adversely interfere with

193 the safe use of the equipment, especially in the case of hand-held or portable equipment,

194 irrespective of its position.

195 Annex H of this standard is applicable to thermal-link packaged assemblies where the

196 thermal-link(s) has already been approved to this standard but packaged in a metallic or non-

197 metallic housing and provided with terminals/wiring leads.

198 This standard is applicable to thermal-links with a rated voltage not exceeding 690 V AC or

199 DC and a rated current not exceeding 63 A.
200 The objectives of this standard are:
201 a) to establish uniform requirements for thermal-links,
202 b) to define methods of test,

203 c) to provide useful information for the application of thermal-links in equipment.

204 This standard is not applicable to thermal-links used under extreme conditions such as

205 corrosive or explosive atmospheres.

206 This standard is not applicable to thermal-links to be used in circuits on a.c. with a frequency

207 lower than 45 Hz or higher than 62 Hz.
208 2 Normative references

209 The following documents, in whole or in part, are normatively referenced in this document and

210 are indispensable for its application. For dated references, only the edition cited applies. For

211 undated references, the latest edition of the referenced document (including any

212 amendments) applies.

213 IEC 60065:2014, Audio, video and similar electronic apparatus – Safety requirements

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214 IEC 60112:2003, Method for the determination of the proof and the comparative tracking

215 indices of solid insulating materials
216 IEC 60112:2003/AMD1:2009
217 IEC 60127-2:2014, Miniature fuses – Part 2: Cartridge fuse-links

218 IEC 60216-5:2008, Electrical insulating materials – Thermal endurance properties – Part 5:

219 Determination of relative thermal endurance index (RTE) of an insulating material

220 IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems – Part 1:

221 Principles, requirements and tests

222 IEC 60695-2-12:2010, Fire hazard testing – Part 2-12: Glowing/hot-wire based test methods –

223 Glow-wire flammability index (GWFI) test method for materials
224 IEC 60695-2-12:2010/AMD1:2014

225 IEC 60695-2-13:2010, Fire hazard testing – Part 2-13: Glowing/hot-wire based test methods –

226 Glow-wire ignition temperature (GWIT) test method for materials
227 IEC 60695-2-13:2010/AMD1:2014

228 IEC 60695-10-2:2014, Fire hazard testing – Part 10-2: Abnormal heat – Ball pressure test

229 method

230 IEC 60695-11-10:2013, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and

231 vertical flame test methods

232 IEC 60730-1:2015, Automatic electrical controls – Part 1: General requirements

233 IEC 61210:2010, Connecting devices – Flat quick-connect terminations for electrical copper

234 conductors – Safety requirements
235 3 Terms and definitions

236 For the purposes of this document, the following terms and definitions apply.

237 3.1
238 clearance
239 shortest distance in air between two conductive parts
240 3.2
241 creepage distance

242 shortest distance along the surface of insulating material between two conductive parts

243 3.3
244 holding temperature
245 T

246 maximum ambient temperature of the thermal-link at which it will not change its state of

247 conductivity during a specified time at a specified rated current
248 3.4
249 homogeneous series

250 series of thermal-links having the same external dimensions and common overall construction,

251 deviating from each other only in such characteristics (including ratings) that, for a given test,

252 the testing of one or a reduced number of particular thermal-links of that series shall be taken

253 as representative for all the thermal-links of the series
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254 3.5
255 interrupting current
256 I

257 value of the current that the thermal-link is capable of interrupting at rated voltage and under

258 specified circuit conditions
259 3.6
260 maximum temperature limit
261 T

262 temperature of the thermal-link stated by the manufacturer, up to which the mechanical and

263 electrical properties of the thermal-link, having changed its state of conductivity, will not be

264 impaired for a given time
265 3.7
266 pilot duty

267 rating assigned to a switching device that controls the coil of another electro-mechanical

268 device such as a solenoid, relay or contactor
269 3.8
270 portable equipment

271 equipment which is moved while in operation or which can easily be moved from one place to

272 another while connected to the supply
273 3.9
274 rated current
275 I
276 current used to classify a thermal-link
277 3.10
278 rated functioning temperature
279 T

280 temperature of the thermal-link which causes it to change its state of conductivity with a

281 detection current up to 10 mA as the only load
282 3.11
283 rated voltage
284 U
285 voltage used to classify a thermal-link
286 3.12
287 thermal element

288 metallic or non-metallic fusible material that is part of a thermal-link and is responsive to

289 temperature by a change of state such as from solid to liquid at the temperature for which it is

290 calibrated
291 3.13
292 thermal-link

293 non-resettable device incorporating a thermal element, which will open a circuit once only

294 when exposed for a sufficient length of time to a temperature in excess of that for which it has

295 been designed
296 3.14
297 transient overload current
298 I

299 direct current pulse train which the thermal-link is able to withstand without impairing its

300 characteristics
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301 3.15
302 extended holding temperature
303 T
h-100

304 maximum temperature at which a thermal-link can be maintained while conducting the rated

305 current at the rated voltage for a period of 100 weeks which will not cause the thermal-link to

306 open circuit in accordance with extended holding temperature evaluation

307 Note 1 to entry: This is a rating for user consideration during the investigation of the end product.

308 Note 2 to entry: Annex D specifies the extended holding temperature evaluation.

309 3.16
310 conductive heat ageing test
311 CHAT
312 test to evaluate a thermal-link for use in an appliance

313 Note 1 to entry: If it performs satisfactorily, the thermal-link will be assigned a CHAT rating. This rating is for end-

314 product user consideration during the investigation of the end-use product.
315 Note 2 to entry: Annex C specifies the conductive heat ageing test.
316 4 General requirements

317 4.1 Adequate protection of the equipment against excessive temperatures not only

318 depends upon the properties of the thermal-link but also to a large extent upon the mounting

319 of the thermal-link in the equipment. Therefore, in addition to good engineering practice, the

320 requirements of the application guide in Annex A shall be considered.

321 4.2 Thermal-links shall have adequate electrical and mechanical strength and shall be

322 constructed so as to withstand all conditions of handling likely to be encountered during

323 mounting and normal use, when used within the requirements of this standard.

324 4.3 When a thermal-link changes its state of conductivity, no arc or flame shall be

325 maintained, nor material expelled, that might impair the surrounding area or otherwise create

326 a risk of electric shock or fire. In addition, there shall be no emission of substances (e.g.

327 gases, liquids, dust, mist, vapour) which could cause a hazard.

328 For thermal-links using melting strips or wires, care should be taken to prevent molten

329 material from short-circuiting or bridging creepage distances and clearances in air, so as to

330 reduce the risk of impairing the insulation system of the equipment.

331 After it has functioned, the thermal-link shall not be damaged when subjected to temperatures

332 not exceeding T , in such a way that the safety of the equipment with regard to risk of electric

333 shock hazard and electrical breakdown is impaired. The thermal-link shall not reclose after it has

334 operated.
335 4.4 For requirements for thermal-link packaged assemblies, see Annex H.
336 5 General notes on tests
337 5.1 The test conditions are as follows.
338 5.1.1 Unless othe
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