EN 60269-4:2007

SLOVENSKI STANDARD
01-november-2007
1DGRPHãþD
SIST EN 60269-4:1998
SIST EN 60269-4:1998/A1:1998
SIST EN 60269-4:1998/A2:2004
SIST EN 60269-4-1:2003
1L]NRQDSHWRVWQHYDURYDONH±GHO'RGDWQH]DKWHYH]DWDOMLYHYORåNH]D]DãþLWR
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Low-voltage fuses -- Part 4: Supplementary requirements for fuse-links for the protection
of semiconductor devices (IEC 60269-4:2006)
Niederspannungssicherungen -- Teil 4: Zusätzliche Anforderungen an
Sicherungseinsätze zum Schutz von Halbleiter-Bauelementen (IEC 60269-4:2006)
Fusibles basse tension -- Partie 4: Exigences supplémentaires concernant les éléments
de remplacement utilisés pour la protection des dispositifs a semiconducteurs (IEC
60269-4:2006)
Ta slovenski standard je istoveten z: EN 60269-4:2007
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 60269-4
NORME EUROPÉENNE
May 2007
EUROPÄISCHE NORM
ICS 29.120.50 Supersedes EN 60269-4:1996 + A1:1997 + A2:2003 and EN 60269-4-1:2002

English version
Low-voltage fuses -
Part 4: Supplementary requirements for fuse-links
for the protection of semiconductor devices
(IEC 60269-4:2006)
Fusibles basse tension -  Niederspannungssicherungen -
Partie 4: Exigences supplémentaires Teil 4: Zusätzliche Anforderungen
concernant les éléments an Sicherungseinsätze zum Schutz
de remplacement utilisés von Halbleiter-Bauelementen
pour la protection des dispositifs (IEC 60269-4:2006)
à semiconducteurs
(CEI 60269-4:2006)
This European Standard was approved by CENELEC on 2007-03-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60269-4:2007 E
Foreword
The text of document 32B/485/FDIS, future edition 4 of IEC 60269-4, prepared by SC 32B, Low-voltage
fuses, of IEC TC 32, Fuses, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 60269-4 on 2007-03-01.
This European Standard supersedes EN 60269-4:1996 + A1:1997 + A2:2003 and EN 60269-4-1:2002.
This part is to be used in conjunction with EN 60269-1:2007, Part 1:General requirements.
This Part 4 supplements or modifies the corresponding clauses or subclauses of Part 1.
Where no change is necessary, this Part 4 indicates that the relevant clause or subclause applies.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2008-03-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2010-03-01
Tables and figures which are additional to those in Part 1 are numbered starting from 101.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60269-4:2006 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 60269-4:2007
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60269-1 - Low-voltage fuses - EN 60269-1 2007
Part 1: General requirements
1) 2)
IEC 60269-2 (mod) - Low-voltage fuses - HD 60269-2 2007
Part 2: Supplementary requirements for fuses
for use by authorized persons (fuses mainly
for industrial application) - Examples of
standardized systems of fuses A to I

1) 2)
IEC 60269-3 (mod) - Low-voltage fuses - HD 60269-3 2007
Part 3: Supplementary requirements for fuses
for use by unskilled persons (fuses mainly for
household or similar applications) - Examples
of standardized systems of fuses A to F

IEC 60417 data- Graphical symbols for use on equipment - -
base
1)
ISO 3 - Preferred numbers - Series of preferred - -
numbers
1)
Undated reference.
2)
Valid edition at date of issue.

NORME CEI
INTERNATIONALE
IEC
60269-4
INTERNATIONAL
Quatrième édition
STANDARD
Fourth edition
2006-11
Fusibles basse tension –
Partie 4:
Exigences supplémentaires concernant les
éléments de remplacement utilisés pour la
protection des dispositifs à semiconducteurs

Low-voltage fuses –
Part 4:
Supplementary requirements for fuse-links
for the protection of semiconductor devices
© IEC 2006 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.
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Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
XA
PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

60269-4 © IEC:2006 – 3 –
CONTENTS
FOREWORD.9
INTRODUCTION .

1 General.15
1.1 Scope.15
1.2 Object.8
2 Terms and definitions .15
2.2 General terms.17
3 Conditions for operation in service.17
3.4 Voltage.17
3.4.1 Rated voltage.17
3.4.2 Applied voltage in service.19
3.5 Current.19
3.6 Frequency, power factor and time constant .19
3.6.1 Frequency.19
3.6.3 Time constant (τ).19
3.10 Temperature inside an enclosure .21
4 Classification.21
5 Characteristics of fuses .21
5.1 Summary of characteristics.21
5.1.2 Fuse-links.21
5.2 Rated voltage.21
5.4 Rated frequency.21
5.5 Rated power dissipation of the fuse-link .21
5.6 Limits of time-current characteristics .23
5.6.1 Time-current characteristics, time-current zones .23
5.6.2 Conventional times and currents.23
5.6.3 Gates.25
5.6.4 Overload curves.25
5.7.1 Breaking range and utilization category .25
5.7.2 Rated breaking capacity .27
5.8 Cut-off current and I t characteristics.27
5.8.1 Cut-off current characteristics.27
5.8.2 I t characteristics .27
5.9 Arc voltage characteristics .29
6 Markings.29
6.2 Markings on fuse-links.29
7 Standard conditions for construction.31
7.3 Temperature rise and power dissipation of the fuse-link .31
7.4 Operation.31
7.5 Breaking capacity.31
7.7 I t characteristics .31
7.14 Arc voltage characteristics .31
7.15 Special operating conditions.31

60269-4 © IEC:2006 – 5 –
8 Tests.33
8.1 eneral.33
8.1.4 Arrangement of the fuse-link.33
8.1.5 Testing of fuse-links.33
8.3 Verification of temperature rise limits and power dissipation.35
8.3.1 Arrangement of the fuse-link.35
8.3.3 and 8.3.4.2 Measurement of power dissipation of the fuse-link .37
8.3.5 Acceptability of test results.37
8.4 Verification of operation.37
8.4.1 Arrangement of fuse-link.37
8.4.3 Test method and acceptability of test results .37
8.5 Verification of the breaking capacity .41
8.5.1 Arrangement of the fuse .41
8.5.5 Test method.41
8.5.8 Acceptability of test results.45
8.6 Verification of the cut-off current characteristic.47
8.6.1 Test method.47
8.6.2 Acceptability of test results.49
8.7 Verification of the I t characteristics and over-current discrimination.51
8.7.1 Test method .51
8.7.2 Acceptability of test results.51
8.7.3 Verification of compliance for “gG” and “gM” fuse-links.51
8.7.4 Verification of overcurrent discrimination .51
8.7.5 Verification of arc voltage characteristics and acceptability of test
results .51

Annex A (informative) Guide for the coordination of fuse-links with semiconductor
devices .61
Annex B (normative) Survey on information to be supplied by the manufacturer in his
literature (catalogue) for a fuse designed for the protection of semiconductor devices .75
Annex C (normative) Examples of standardized fuse-links for the protection of
semiconductor devices .77

Figure 101 – Conventional overload curve (example) (X and Y are points of verified
overload capability).53
Figure 102 – Example of a conventional test arrangement (continued on page 57) .55
Figure 103 – Example of a conventional test arrangement .59
Figure C.1 – Single body fuse-links.79
Figure C.2 – Double body fuse-links .81
Figure C.3 – Twin body fuse-links .83
Figure C.4 – Trip indicator fuse-links .83
Figure C.5 – Fuse-links with bolted connections, type B, body sizes 000 and 00.87
Figure C.6 – Fuse-links with bolted connections, type B, body sizes 0, 1, 2 and 3.89

60269-4 © IEC:2006 – 7 –
Figure C.7– Bolted fuse-links, type C .93
Figure C.8 – Flush end fuse-links, type A.97
Figure C.9 – Flush end fuse-links, type B.101
Figure C.10 – Fuse-links with cylindrical contact caps, type A.105

Table 101 – Conventional times and currents for “gR” and “gS” fuse-links .25
Table 102 – List of complete tests.33
Table 103 – Survey of tests on fuse-links of the smallest rated current of a
homogeneous series.35
Table 104 – Values for breaking-capacity tests on a. c. fuses .45
Table 105 – Values for breaking-capacity tests on d.c. fuses .47
Table 106 – Values for verification of cut-off current, I t and arc voltage
characteristics tests for a.c. .49

60269-4 © IEC:2006 – 9 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE FUSES –
Part 4: Supplementary requirements for fuse-Iinks
for the protection of semiconductor devices

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60269-4 has been prepared by subcommittee 32B: Low-voltage
fuses, of IEC technical committee 32: Fuses.
This fourth edition cancels and replaces the third edition published in 1986, amendment 1
(1995) and amendment 2 (2002) as well as IEC 60269-4-1(2002) and constitutes a minor
revision.
The general re-organization of the IEC 60269 series has led to the creation of this new
edition.
This part is to be used in conjunction with IEC 60269-1:2006, Part 1:General requirements.
This Part 4 supplements or modifies the corresponding clauses or subclauses of Part 1.

60269-4 © IEC:2006 – 11 –
Where no change is necessary, this Part 4 indicates that the relevant clause or subclause
applies.
Tables and figures which are additional to those in Part 1 are numbered starting from 101.
The text of this standard is based on following documents:
FDIS Report on voting
32B/485/FDIS 32B/492/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.
IEC 60269 consists of the following parts, under the general title Low-voltage fuses:
Part 1: General requirements
NOTE This part includes the IEC 60269-1 (third edition, 1998) and parts of the IEC 60269-2
(second edition, 1986) and IEC 60269-3 (second edition, 1987).
Part 2: Supplementary requirements for fuses for use by authorized persons (fuses
mainly for industrial application) – Examples of standardized systems of fuses A
to I
NOTE This part includes parts of the IEC 60269-2 (second edition, 1986) and the entire IEC 60269-
2-1 (fourth edition, 2004).
Part 3: Supplementary requirements for fuses for use by unskilled persons (fuses mainly
for household or similar application) – Examples of standardized systems of fuses
A to F
NOTE This part includes parts of the IEC 60269-3 (second edition, 1987) and the entire IEC 60269-
3-1 (second edition, 2004).
Part 4: Supplementary requirements for fuse-links for the protection of semiconductor
devices
NOTE This part includes the IEC 60269-4 (third edition, 1986) and the IEC 60269-4-1 (first edition,
2002).
Part 5: Guidance for the application of low-voltage fuses
NOTE Currently IEC/TR 61818 (2003).
For reasons of convenience, when a part of this publication has come from other publications,
a remark to this effect has been inserted in the text.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
60269-4 © IEC:2006 – 13 –
INTRODUCTION
A reorganization of the different parts of the IEC 60269 series has been carried out, in order
to simplify its use, especially by the laboratories which test the fuses.
IEC 61269-1, IEC 60269-2, IEC 60269-3 and IEC 60269-3-1 have been integrated into either
the new part 1 or the new parts 2 or 3, according to the subjects considered, so that the
clauses which deal exclusively with “fuses for authorized persons” are separated from the
clauses dealing with “fuses for unauthorized persons”.
As far as IEC 60269-4 and IEC 60269-4-1 are concerned, they have been integrated into the
new part 4 which deals with the fuse-links used for semiconductor protection.

60269-4 © IEC:2006 – 15 –
LOW-VOLTAGE FUSES –
Part 4: Supplementary requirements for fuse-links
for the protection of semiconductor devices

1 General
IEC 60269-1 applies with the following supplementary requirements.
Fuse-links for the protection of semiconductor devices shall comply with aIl requirements of
IEC 60269-1, if not otherwise indicated hereinafter, and shall also comply with the
supplementary requirements laid down below.
1.1 Scope and object
These supplementary requirements apply to fuse-links for application in equipment containing
semiconductor devices for circuits of nominal voltages up to 1 000 V a.c. or 1 500 V d.c. and
also, in so far as they are applicable, for circuits of higher nominal voltages.
NOTE 1 Such fuse-Iinks are commonly referred to as “semiconductor fuse-links”.
NOTE 2 In most cases, a part of the associated equipment serves the purpose of a fuse-base. Owing to the great
variety of equipment, no general rules can be given; the suitability of the associated equipment to serve as a fuse-
base should be subject to agreement between the manufacturer and the user. However, if separate fuse-bases or
fuse-holders are used, they should comply with the appropriate requirements of IEC 60269-1.
The object of these supplementary requirements is to establish the characteristics of
semiconductor fuse-links in such a way that they can be replaced by other fuse-links having
the same characteristics, provided that their dimensions are identical. For this purpose, this
standard refers in particular to
a) The following characteristics of fuses:
1) their rated values;
2) their temperature rises in normal service;
3) their power dissipation;
4) their time-current characteristics;
5) their breaking capacity;
6) their cut-off current characteristics and their I t characteristics;
7) their arc voltage limits.
b) Type tests for verification of the characteristics of fuses.
c) The markings on fuses.
d) Availability and presentation of technical data (see Annex B).
1.2 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 60269-1, Low-voltage fuses – General requirements

60269-4 © IEC:2006 – 17 –
IEC 60269-2, Low-voltage fuses – Supplementary requirements for fuses for use by
authorized persons (fuses mainly for industrial application) – Examples of standardized
systems of fuses A to I
IEC 60269-3, Low-voltage fuses – Supplementary requirements for fuses for use by unskilled
persons (fuses mainly for household or similar application) – Examples of standardized
systems of fuses A to F
IEC 60417, Graphical symbols for use on equipment
ISO 3, Preferred numbers – Series of preferred numbers
2 Terms and definitions
IEC 60269-1 applies with the following supplementary requirements.
2.2 General terms
2.2.101
semiconductor device
Remark: previously 2.1.14 in IEC 60269-4, Amendment 2
device whose essential characteristics are due to the flow of charge carriers within a
semiconductor
[IEV 521-04-01]
2.2.102
semiconductor fuse-link
Remark: previously 2.1.15 in IEC 60269-4, Edition 3
current-limiting fuse-link capable of breaking, under specific conditions, any current value
within the breaking range (see 7.4)
2.2.103
signalling device
Remark: previously 2.1.16 in IEC 60269-4, Amendment 2
device forming part of the fuse and signalling the fuse operation to a remote place.
A signalling device consists of a striker and an auxiliary switch. Electronic devices may also
be used
3 Conditions for operation in service
IEC 60269-1 applies with the following supplementary requirements.
3.4 Voltage
3.4.1 Rated voltage
For a.c., the rated voltage of a fuse-link is related to the applied voltage; it is based on the
r.m.s. value of a sinusoidal a.c. voltage. It is further assumed that the applied voltage retains
the same value throughout the operation of the fuse-link. All tests to verify the ratings are
based on this assumption.
NOTE In many applications, the applied voltage will be sufficiently close to the sinusoidal form for the significant
part of the operating time, but there are many cases where this condition is not satisfied.

60269-4 © IEC:2006 – 19 –
The performance of a fuse-link subjected to a non-sinusoidal applied voltage can be
evaluated by comparing, for the first approximation, the arithmetic mean values of the non-
sinusoidal and sinusoidal applied voltages.
For d.c., the rated voltage of a fuse-link is related to the applied voltage. It is based on the
mean value. When d.c. is obtained by rectifying a.c., the ripple is assumed not to cause a
variation of more than 5 % above or 9 % below the mean value.
3.4.2 Applied voltage in service
Under service conditions, the applied voltage is that voltage which, in the fault circuit, causes
the current to increase to such proportions that the fuse-link will operate.
For a.c., consequently, the value of the applied voltage in a single-phase a.c. circuit is usually
identical to the power-frequency recovery voltage. For all cases other than the sinusoidal a.c.
voltage, it is necessary to know the applied voltage as a function of time. For a unidirectional
voltage, the important values are:
– the average value over the entire period of the operation of the fuse-link;
– the instantaneous value near the end of the arcing period.
For d.c., the value of the applied voltage is usually approximately the same as the mean
recovery voltage.
3.5 Current
The rated current of a semiconductor fuse-link is based on the r.m.s. value of a sinusoidal a.c.
current at rated frequency.
For d.c. the r.m.s. value of current is assumed not to exceed the r.m.s. value based on a
sinusoidal a.c. current at rated frequency.
NOTE The thermal response time of the fuse-element may be so short that it cannot be assumed that operation
under conditions which deviate much from sinusoidal current can be estimated on the basis of the r.m.s. current
alone. This is so, in particular at lower frequency values and when the current presents salient peaks separated by
appreciable intervals of insignificant current; for example, in the case of frequency converters and traction
applications.
3.6 Frequency, power factor and time constant
3.6.1 Frequency
The rated frequency refers to the frequency of the sinusoidal current and voltage that form the
basis of the type tests.
NOTE In particular, where service frequency deviates significantly from rated frequency the manufacturer should
be consulted.
3.6.3 Time constant (τ)
For d.c., the time constants expected in practice are considered to correspond to those in
Table 105.
NOTE Some service conditions may be found which exceed the specified performance shown in the table as
regards time constant. In such a case, a design of fuse-link which has been tested and marked accordingly should
be used or the suitability of such a fuse-link be subject to agreement between manufacturer and user.

60269-4 © IEC:2006 – 21 –
3.10 Temperature inside an enclosure
Since the rated values of the fuse-links are based on specified conditions that do not always
correspond to those prevailing at the point of installation, including the local air conditions,
the user may have to consult the manufacturer concerning the possible need for re-rating.
4 Classification
IEC 60269-1 applies.
5 Characteristics of fuses
IEC 60269-1 applies with the following supplementary requirements.
5.1 Summary of characteristics
5.1.2 Fuse-links
a) Rated voltage (see 5.2).
b) Rated current (see 5.3 of IEC 60269-1).
c) Kind of current and frequency (see 5.4 of IEC 60269-1).
d) Rated power dissipation (see 5.5 of IEC 60269-1).
e) Time-current characteristics (see 5.6).
f) Breaking range (see 5.7.1 of IEC 60269-1).
g) Rated breaking capacity (see 5.7.2 of IEC 60269-1).
h) Cut-off current characteristics (see 5.8.1).

i) I t characteristics (see 5.8.2).
k) Dimensions or size (if applicable).
l) Arc voltage limits (see 5.9).
5.2 Rated voltage
For rated a.c. voltages up to 690 V and d.c. voltages up to 750 V, IEC 60269-1 applies; for
higher voltages, the values shall be selected from the R5 series or, where not possible, from
the R10 series of ISO 3.
5.4 Rated frequency
The rated frequency is that frequency to which the performance data are related.
5.5 Rated power dissipation of the fuse-link
In addition to the requirements of IEC 60269-1, the manufacturer shall indicate the power
dissipation as a function of current for the range 50 % to 100 % of the rated current or for
50 %, 63 %, 80 % and 100 % of the rated current.
NOTE In cases where the resistance of the fuse-link is of interest, this resistance should be determined from the
functional relation between the power dissipation and the associated value of current.

60269-4 © IEC:2006 – 23 –
5.6 Limits of time-current characteristics
5.6.1 Time-current characteristics, time-current zones
The time-current characteristics of a fuse-link vary according to its design and also, for a
given fuse-link, depend on the ambient temperature and the cooling conditions.
The manufacturer shall provide time-current characteristics based on an ambient temperature
of 20 °C to 25 °C in accordance with the conditions specified in 8.3. The time-current
characteristics of interest are the pre-arcing characteristic and operating characteristics
having voltage as a parameter. The time-current characteristics are stated for rated
frequency.
For d.c. they are stated for time constants according to Table 105.
For some applications, and in particular for the higher values of prospective current (shorter
times), the same information may be presented in the form of I t characteristics. It is
recommended that in this region, I t characteristics shall be given as an alternative or in
addition.
5.6.1.1 Pre-arcing time-current characteristics
For a.c., the pre-arcing time-current characteristic shall be based on a symmetrical a.c.
current of a stated value of frequency (rated frequency).
NOTE This is of particular importance for the range of time between about ten cycles of rated frequency and a
time so short that the heating is truly adiabatic.
For d.c., the pre-arcing time-current characteristic is of particular significance for times
exceeding 15 τ for the relevant circuit, and is identical to the a.c. pre-arcing time-current
characteristic in this zone.
NOTE 1 Because of the wide range of circuit time constants likely to be experienced in service, the information
for times shorter than 15 τ is conveniently expressed as a pre-arcing I t characteristic.
NOTE 2 The value of 15 τ has been chosen to avoid the effects which different rates of rise of current have on the
pre-arcing time-current characteristic at shorter times.
5.6.1.2 Operating time-current characteristics
The operating time-current characteristics shall be given with applied voltage as a parameter
and for a stated power-factor value. In principle, they shall be based on the moment of current
initiation that leads to the highest operating I t value (see 8.7). The voltage parameters shall
include at least 100 %, 50 % and 25 % of the rated voltage.
For d.c., the operating time-current characteristics are not applicable because they are not
significant for times in excess of 15 τ (see 5.6.1.1).
5.6.2 Conventional times and currents
5.6.2.1 Conventional times and currents for “aR” fuse-links
Not applicable.
60269-4 © IEC:2006 – 25 –
5.6.2.2 Conventional times and currents for “gR” and “gS” fuse-links
The conventional times and currents are given in Table 101.
Table 101 – Conventional times and currents for “gR” and “gS” fuse-links
Remark: this table refers to Table 2 in IEC 60269-1
and was previously Table II in IEC 60269-4, Amendment 2
Conventional current
Rated current Conventional time
Type “gR” Type “gS”
A h
I I I I
nf f nf f
I ≤ 63
n
63 < I ≤ 160
n
1,1 I 1,6 I 1,25 I 1,6 I
n n n n
160 < I ≤ 400
n
400 < I 4
n
5.6.3 Gates
Not applicable.
5.6.4 Overload curves
5.6.4.1 Verified overload capability
The manufacturer shall indicate sets of coordinate points along the time-current
characteristics (see 5.6.1) for which the overload capability has been verified in accordance
with the procedure indicated in 8.4.3.4.
The number and the location of the sets of coordinate points for which the overload capability
shall be verified shall be selected at the discretion of the manufacturer. The time coordinates
for the verification of the overload capability shall he selected within the range of 0,01s to
60 s. Further sets of the coordinate points may be added according to agreement between
manufacturer and user.
5.6.4.2 Conventional overload curve
The conventional overload curve is formed of straight-line sections emanating from the co-
ordinate points of verified overload capability. From each set of coordinate points, two lines
are drawn:
– one from the verified point and following points of constant values of current towards
shorter times;
– the other from the verified point and following points of constant values of I t towards
longer times.
These line sections, ending at the line representing rated current, form the conventional
overload curve (see Figure 101).
NOTE For practical applications, a few points of verified overload capability are sufficient. As the number of
points of verified overload capability increases, the conventional overload curve becomes more precise.
5.7.1 Breaking range and utilization category
The first letter shall indicate the breaking range:
− “a” fuse-links (partial-range breaking capacity, see 7.4);

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− “g” fuse-links (full-range breaking capacity).
The second letter “R” and “S” shall indicate the utilization category for fuse-links complying
with this standard for the protection of semiconductor devices.
The type “R” is faster acting than type “S” and gives lower I t values.
The type “S” has lower power dissipation and gives enhanced utilization of cables compared
to type “R”.
5.7.2 Rated breaking capacity
A breaking capacity of at least 50 kA for a.c. and 8 kA for d.c. is recommended.
For a.c., the rated breaking capacity is based on type tests performed in a circuit containing
only linear impedance and with a constant sinusoidal applied voltage of rated frequency.
For d.c., the rated breaking capacity is based on type tests performed in a circuit containing
only linear inductance and resistance with mean applied voltage.
NOTE The addition in practical applications of non-linear impedances and unidirectional voltage components may
significantly influence the breaking severity either in a favourable or unfavourable direction.
5.8 Cut-off current and I t characteristics
5.8.1 Cut-off current characteristics
The manufacturer shall provide the cut-off current characteristics which shall be given,
according to the example shown in Figure 4 of IEC 60269-1, in a double logarithmic
presentation with the prospective current as abscissa and, if necessary, with applied voltage
and/or frequency as a parameter.
For a.c., the cut-off current characteristics shall represent the highest values of current likely
to be experienced in service. They shall refer to the conditions corresponding to the test
conditions of this standard, for example, given voltage, frequency and power-factor values.
The cut-off current characteristics are verified by the tests specified in 8.6.
For d.c., the cut-off current characteristics shall represent the highest values of current likely
to be experienced in service in circuits having a time constant specified in the Table 105.
These values will be exceeded in circuits of smaller time constants. The manufacturer shall
provide the relevant information to enable the determination of these higher cut-off current
characteristics.
NOTE The cut-off current characteristic varies with the circuit time constant. The manufacturer should provide the
relevant information to enable these variations to be determined at least for time constants of 5 ms and 10 ms.
5.8.2 I t characteristics
5.8.2.1 Pre-arcing I t characteristic
For a.c., the pre-arcing I t characteristic shall be based on a symmetrical a.c. current at a
stated frequency value (rated frequency).

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For d.c., the pre-arcing I t characteristic shall be based on r.m.s. d.c. current at a time
constant specified in Table 105.
NOTE For certain fuses, the pre-arcing I t characteristic varies with the circuit time constant. The manufacturer
should provide the relevant information to enable these variations to be determined at least for time constants of
5 ms and 10 ms.
5.8.2.2 Operating I t characteristics
For a.c., the operating I t characteristics shall be given with applied voltage as a parameter
and for a stated power-factor value. In principle, they shall be based on the moment of current
initiation that leads to the highest operating I t value (see 8.7). The voltage parameters shall
include at least 100 %, 50 % and 25 % of rated voltage.
For d.c., the operating I t characteristics shall be given with the applied voltage as a
parameter and for a time constant specified in the Table 105. The voltage parameters shall
include at least 100 % and 50 % of rated voltage. It is permitted to determine the operating I t
characteristics at lower voltages from tests in accordance with Table 105.
5.9 Arc voltage characteristics
Arc voltage characteristics provided by the manufacturer shall give the highest (peak) value of
arc voltage as a function of the applied voltage of the circuit in which the fuse-link is inserted
and, in the case of a.c., for power factors as stated in Table 106 and, in the case of d.c. at
time constants specified in Table 105.
6 Markings
IEC 60269-1 applies with the following supplementary requirements.
6.2 Markings on fuse-links
Subclause 6.2 of IEC 60269-1 applies with the following addition:
– manufacturer's identification reference and/or symbols enabling all the characteristics
listed in 5.1.2 of IEC 60269-1 to be found;
– utilization category, “aR” or “gR” or “gS”;
– a combination of symbols of IEC 60417 of a fuse (5016) and a rectifier (5186) as shown
below:
Symbol IEC 60417-5016 Symbol IEC 60417-5186

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7 Standard conditions for c
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