EN IEC 60282-1:2020
(Main)High-voltage fuses - Part 1: Current-limiting fuses
High-voltage fuses - Part 1: Current-limiting fuses
IEC 60282-1:2020 applies to all types of high-voltage current-limiting fuses designed for use outdoors or indoors on alternating current systems of 50 Hz and 60 Hz and of rated voltages exceeding 1 000 V. This eighth edition cancels and replaces the seventh edition published in 2009. This edition includes the following significant technical changes with respect to the previous edition: – additional information concerning thermally operated strikers; – the division of ratings, characteristics and type tests into those applicable to all fuses and those applicable to particular fuse-link types and applications; – adjustment of Series II voltages and tests to meet present North American standard system voltages and applications; – clarification of requirements for fuse-links used in surrounding temperatures above 40 °C; and – clarification of homogeneous requirements for fuse-links containing one element.
Hochspannungssicherungen - Teil 1: Strombegrenzende Sicherungen
Fusibles à haute tension - Partie 1: Fusibles limiteurs de courant
IEC 60282-1:2020 s'applique à tous les types de fusibles à haute tension limiteurs de courant destinés à être utilisés à l'extérieur ou à l'intérieur sur des réseaux à courant alternatif 50 Hz et 60 Hz et dont les tensions assignées sont supérieures à 1 000 V. Cette huitième édition annule et remplace la septième édition parue en 2009. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: – des informations supplémentaires concernant les percuteurs thermiques; – la division des valeurs assignées, des caractéristiques et des essais de type en un groupe qui s'applique à tous les fusibles et en un groupe qui s'applique à des types particuliers d'éléments de remplacement et des applications; – le réglage des tensions de la Série II et les essais pour satisfaire aux tensions réseaux normalisées actuelles et aux applications d'Amérique du Nord; – la clarification des exigences pour les éléments de remplacement utilisés avec des températures environnantes supérieures à 40 °C; – et la clarification d'exigences homogènes pour les éléments de remplacement contenant un élément.
Visokonapetostne varovalke - 1. del: Tokovno omejilne varovalke (IEC 60282-1:2020)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2020
Nadomešča:
SIST EN 60282-1:2010
SIST EN 60282-1:2010/A1:2014
Visokonapetostne varovalke - 1. del: Tokovno omejilne varovalke (IEC 60282-
1:2020)
High-voltage fuses - Part 1: Current-limiting fuses (IEC 60282-1:2020)
Hochspannungssicherungen - Teil 1: Strombegrenzende Sicherungen (IEC 60282-
1:2020)
Fusibles à haute tension - Partie 1: Fusibles limiteurs de courant (IEC 60282-1:2020)
Ta slovenski standard je istoveten z: EN IEC 60282-1:2020
ICS:
29.120.50 Varovalke in druga Fuses and other overcurrent
nadtokovna zaščita protection devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 60282-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2020
ICS 29.120.50 Supersedes EN 60282-1:2009 and all of its amendments
and corrigenda (if any)
English Version
High-voltage fuses - Part 1: Current-limiting fuses
(IEC 60282-1:2020)
Fusibles à haute tension - Partie 1: Fusibles limiteurs de Hochspannungssicherungen - Teil 1: Strombegrenzende
courant Sicherungen
(IEC 60282-1:2020) (IEC 60282-1:2020)
This European Standard was approved by CENELEC on 2020-05-19. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60282-1:2020 E
European foreword
The text of document 32A/347/FDIS, future edition 8 of IEC 60282-1, prepared by SC 32A "High-
voltage fuses" of IEC/TC 32 "Fuses" was submitted to the IEC-CENELEC parallel vote and approved
by CENELEC as EN IEC 60282-1:2020.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2021-02-19
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2023-05-19
document have to be withdrawn
This document supersedes EN 60282-1:2009 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 60282-1:2020 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60085:2007 NOTE Harmonized as EN 60085:2008 (not modified)
IEC 62271-100:2008 NOTE Harmonized as EN 62271-100:2009 (not modified)
IEC 62271-100:2008/A1:2012 NOTE Harmonized as EN 62271-100:2009/A1:2012 (not modified)
IEC 62271-100:2008/A2:2017 NOTE Harmonized as EN 62271-100:2009/A2:2017 (not modified)
IEC 62271-103 NOTE Harmonized as EN 62271-103
ISO 179 (series) NOTE Harmonized as EN ISO 179 (series)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60060-1 2010 High-voltage test techniques - Part 1: General EN 60060-1 2010
definitions and test requirements
IEC 60071-1 - Insulation co-ordination - Part 1: Definitions, EN IEC 60071-1 -
principles and rules
IEC 60549 - High-voltage fuses for the external protection EN 60549 -
of shunt capacitors
IEC 60644 - Specification for high-voltage fuse-links for EN 60644 -
motor circuit applications
IEC 62271-105 - High-voltage switchgear and controlgear - - -
Part 105: Alternating current switch-fuse
combinations for rated voltages above 1 kV
up to and including 52 kV
IEC 60282-1 ®
Edition 8.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High-voltage fuses –
Part 1: Current-limiting fuses
Fusibles à haute tension –
Partie 1: Fusibles limiteurs de courant
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.50 ISBN 978-2-8322-8088-1
– 2 – IEC 60282-1:2020 © IEC 2020
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
3.1 Electrical characteristics . 8
3.2 Fuses and their component parts . 12
3.3 Additional terms . 14
4 Normal and special service conditions . 16
4.1 Normal service conditions . 16
4.2 Special service conditions . 17
4.2.1 General . 17
4.2.2 Altitude . 17
4.3 Environmental behaviour . 18
5 Ratings and characteristics . 18
5.1 General . 18
5.2 Ratings and characteristics that are applicable to all fuses . 18
5.2.1 Rated voltage (U ) . 18
r
5.2.2 Rated current of a fuse-base . 19
5.2.3 Rated current of a fuse-link (I ) . 19
r
5.2.4 Rated insulation level (of a fuse-base) . 19
5.2.5 Rated breaking capacity . 21
5.2.6 Rated frequency . 21
5.2.7 Temperature limits . 21
5.2.8 Limits of switching voltage . 22
5.2.9 Time-current characteristics . 24
5.2.10 Cut-off characteristic . 25
5.2.11 I t characteristics . 25
5.2.12 Power dissipation . 25
5.3 Ratings and characteristics of particular fuse-link types and applications . 25
5.3.1 Fuse-links for transformer applications . 25
5.3.2 Fuse-links for motor circuit applications . 26
5.3.3 Fuse-links for capacitor protection . 26
5.3.4 Fuses fitted with indicating devices . 26
5.3.5 Back-Up fuses intended for use in a switch-fuse combination according
to IEC 62271-105 . 28
5.3.6 Allowable continuous current of a fuse-link (I ) . 28
a
5.3.7 Maximum enclosure current (I ) . 28
fep
6 Design, construction and performance . 29
6.1 General requirements with respect to fuse operation . 29
6.1.1 General . 29
6.1.2 Standard conditions of use . 29
6.1.3 Standard conditions of behaviour . 30
6.2 Identifying markings . 30
6.3 Dimensions . 31
7 Type tests performed on all fuses . 31
7.1 Conditions for making the tests . 31
IEC 60282-1:2020 © IEC 2020 – 3 –
7.2 List of type tests . 32
7.3 Common test practices for all type tests . 32
7.3.1 General . 32
7.3.2 Mounting of fuse-link . 32
7.3.3 Condition of device to be tested . 32
7.3.4 Mounting of fuses . 32
7.4 Dielectric tests . 32
7.4.1 Test practices . 32
7.4.2 Application of test voltage for impulse and power-frequency test . 33
7.4.3 Atmospheric conditions during test . 33
7.4.4 Lightning impulse voltage dry tests . 33
7.4.5 Power-frequency voltage dry tests . 34
7.4.6 Power-frequency wet tests . 34
7.5 Temperature-rise tests and power-dissipation measurement . 34
7.5.1 Test practices . 34
7.5.2 Measurement of temperature . 35
7.5.3 Measurement of power dissipation . 36
7.6 Breaking tests . 36
7.6.1 Test practices . 36
7.6.2 Test procedure . 46
7.6.3 Alternative test methods for Test Duty 3 . 48
7.6.4 Breaking tests for fuse-links of a homogeneous series . 51
7.6.5 Acceptance of a homogeneous series of Back-Up fuse-links by
interpolation. 53
7.6.6 Acceptance of a homogeneous series of fuse-links of different lengths . 53
7.7 Tests for time-current characteristics . 54
7.7.1 Test practices . 54
7.7.2 Test procedures . 54
7.8 Electromagnetic compatibility (EMC) . 54
8 Type tests for particular fuse-link types and applications . 55
8.1 General . 55
8.2 List of type tests . 55
8.3 Tests required for a particular type of fuse or application . 55
8.3.1 Indicator tests (for fuses fitted with indicators) . 55
8.3.2 Striker tests (for fuses fitted with strikers) . 56
8.3.3 Tests for Back-Up fuses for use in switch-fuse combination of
IEC 62271-105 . 58
8.3.4 Liquid-tightness tests . 59
8.4 Tests performed at the request of a user . 64
8.4.1 Thermal shock tests for outdoor fuses . 64
8.4.2 Waterproof test (ingress of moisture) for outdoor fuses . 65
9 Routine tests . 65
Annex A (normative) Method of drawing the envelope of the prospective and transient
recovery voltage of a circuit and determining the representative parameters . 66
A.1 Introduction . 66
A.2 Drawing the envelope . 66
A.3 Determination of parameters . 66
Annex B (informative) Reasons which led to the choice of TRV values for Test Duties
1, 2 and 3 . 68
– 4 – IEC 60282-1:2020 © IEC 2020
Annex C (informative) Preferred arrangements for temperature-rise tests of liquid-
tight fuse-links . 70
Annex D (informative) Types and dimensions of current-limiting fuse-links specified in
existing national standards . 71
Annex E (normative) Requirements for certain types of fuse-links intended for use at
surrounding temperatures above 40 °C . 74
E.1 Types of fuse-link covered by this annex . 74
E.1.1 General . 74
E.1.2 Covered fuse-link types . 74
E.1.3 Exempted fuse-links . 74
E.1.4 Introduction . 74
E.2 Definitions. 75
E.3 Preferred MAT ratings . 75
E.4 Specific service conditions . 75
E.5 Additional breaking test requirements . 75
E.5.1 Test practices . 75
E.5.2 Test procedure . 76
E.5.3 Full-Range fuse Test Duty 3 tests . 76
E.6 Full-Range fuse: determination of I current . 77
Annex F (informative) Criteria for determining I testing validity . 78
t
F.1 Introduction . 78
F.2 Breaking processes . 78
Bibliography . 79
Figure 1 – Terminology . 13
Figure 2 – Permissible switching voltages for fuse-links of small current ratings
(Table 8) . 24
Figure 3 – Various stages of the striker travel . 27
Figure 4 – Representation of a specified TRV by a two-parameter reference line and a
delay line . 41
Figure 5 – Example of a two-parameter reference line for a TRV complying with the
conditions of the type test . 42
Figure 6 – Breaking tests – Arrangement of the equipment . 46
Figure 7 – Breaking tests – Typical circuit diagram for Test Duties 1 and 2 . 46
Figure 8 – Breaking tests – Typical circuit diagram for Test Duty 3 . 47
Figure 9 – Breaking tests – Interpretation of oscillograms for Test Duty 1 . 49
Figure 10 – Breaking tests – Interpretation of oscillograms for Test Duty 2 (calibration
traces as in a) of Figure 9) . 50
Figure 11 – Breaking tests – Interpretation of oscillograms for Test Duty 3 . 50
Figure 12 – Test sequence for switchgear type applications . 61
Figure 13 – Test sequence for transformer type applications . 62
Figure 14 – Test sequence for series a) test for transformer type applications . 63
Figure 15 – Test sequence for series b) test for transformer type applications . 64
Figure A.1 – Example of a two-parameter reference line for a TRV whose initial portion
is concave towards the left . 67
Figure A.2 – Example of a two-parameter reference line for an exponential TRV . 67
Figure C.1 – Test tank for temperature-rise tests of liquid-tight fuses . 70
IEC 60282-1:2020 © IEC 2020 – 5 –
Figure C.2 – Details of clamping arrangement for fuse-link in the tank . 70
Table 1 – Altitude correction factors – Dielectric withstand. 17
Table 2 – Altitude correction factors – Current-carrying capability . 17
Table 3 – Rated voltages . 19
Table 4 – Fuse-base rated insulation levels – Series I . 20
Table 5 – Fuse-base rated insulation levels – Series II . 20
Table 6 – Limits of temperature and temperature rise for components and materials. 22
Table 7 – Maximum permissible switching voltages. 23
Table 8 – Maximum permissible switching voltages for certain fuse-links of small
current ratings . 23
Table 9 – Striker mechanical characteristics . 27
Table 10 – Electrical connection to the test circuit – Conductor sizes . 35
Table 11 – Breaking tests – Parameters . 39
Table 12 – Standard values of rated TRV for I – Series I rated voltages. 43
Table 13 – Standard values of rated TRV for I – Series II rated voltages. 43
Table 14 – TRV for Test Duty 2 – Series I rated voltages . 44
Table 15 – TRV for Test Duty 2 – Series II rated voltages . 45
Table 16 – Breaking test requirements for fuse-links of a homogeneous series . 52
– 6 – IEC 60282-1:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE FUSES –
Part 1: Current-limiting fuses
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC
Publication(s)"). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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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 60282-1 has been prepared by subcommittee 32A: High-voltage
fuses, of IEC technical committee 32: Fuses.
This eighth edition cancels and replaces the seventh edition published in 2009.
This edition includes the following significant technical changes with respect to the previous
edition:
– additional information concerning thermally operated strikers;
– the division of ratings, characteristics and type tests into those applicable to all fuses and
those applicable to particular fuse-link types and applications;
– adjustment of Series II voltages and tests to meet present North American standard
system voltages and applications;
– clarification of requirements for fuse-links used in surrounding temperatures above 40 °C;
and
IEC 60282-1:2020 © IEC 2020 – 7 –
– clarification of homogeneous requirements for fuse-links containing one element.
The text of this International Standard is based on the following documents:
FDIS Report on voting
32A/347/FDIS 32A/349/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60282 series, published under the general title High-voltage fuses,
can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 8 – IEC 60282-1:2020 © IEC 2020
HIGH-VOLTAGE FUSES –
Part 1: Current-limiting fuses
1 Scope
This part of IEC 60282 applies to all types of high-voltage current-limiting fuses designed for
use outdoors or indoors on alternating current systems of 50 Hz and 60 Hz and of rated
voltages exceeding 1 000 V.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60060-1:2010, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60071-1, Insulation coordination – Part 1: Definitions, principles and rules
IEC 60549, High-voltage fuses for the external protection of shunt capacitors
IEC 60644, Specification for high-voltage fuse-links for motor circuit applications
IEC 62271-105, High-voltage switchgear and controlgear – Part 105: Alternating current
switch-fuse combinations for rated voltages above 1 kV up to and including 52 kV
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Electrical characteristics
3.1.1
rated value
value of a quantity used for specification purposes, established for a specified set of operating
conditions of a component, device, equipment, or system
Note 1 to entry: Examples of rated value usually stated for fuses: voltage, current and breaking current.
[SOURCE: IEC 60050-441:2000, 441-18-35, modified – "used for specification purposes" and
"system" added, "assigned, generally by the manufacturer" deleted.]
IEC 60282-1:2020 © IEC 2020 – 9 –
3.1.2
rating
set of rated values and operating conditions
[SOURCE: IEC 60050-441:2000, 441-18-36]
3.1.3
prospective current (of a circuit and with respect to a fuse)
current that would flow in the circuit if the fuse were replaced by a conductor of negligible
impedance
Note 1 to entry: For the method to evaluate and to express the prospective current, see 7.6.2.1 and 7.6.2.2.
[SOURCE: IEC 60050-441:2000, 441-17-01, modified – deletion of "a switching device or",
"each pole of the switching device or" and "is to be specified in the relevant publications" and
addition of "see 7.6.2.1 and 7.6.2.2".]
3.1.4
prospective peak current
peak value of a prospective current during the transient period following initiation
Note 1 to entry: The definition assumes that the current is made by an ideal switching device, i.e. with instan-
taneous transition from infinite to zero impedance. For circuits where the current can follow several different paths,
for example polyphase circuits, it further assumes that the current is made simultaneously in all poles, even if only
the current in one pole is considered.
[SOURCE: IEC 60050-441:2000, 441-17-02]
3.1.5
prospective breaking current
RMS value of the AC component of the prospective current, evaluated at a specified time
Note 1 to entry: This specified time is given in 7.6.2.3.
3.1.6
breaking capacity
value of prospective current that a fuse-link is capable of breaking at a stated voltage under
prescribed conditions of use and behaviour
[SOURCE: IEC 60050-441:2000, 441-17-08, modified – "switching device or a fuse" replaced
with "fuse-link" and Notes removed.]
3.1.7
cut-off current
let-through current
maximum instantaneous value of current attained during the breaking operation of a fuse
Note 1 to entry: This concept is of particular importance when the fuse operates in such a manner that the
prospective peak current of the circuit is not reached due to a current-limiting effect.
[SOURCE: IEC 60050-441:2000, 441-17-12, modified – "a switching device or" deleted, "due
to a current limiting effect" added to Note 1 to entry.]
3.1.8
pre-arcing time
melting time
interval of time between the beginning of a current large enough to cause a break in the
fuse-element(s) and the instant when an arc is initiated
[SOURCE: IEC 60050-441:2000, 441-18-21]
– 10 – IEC 60282-1:2020 © IEC 2020
3.1.9
arcing time
interval of time between the instant of the initiation of the arc in a fuse and the instant of final
arc extinction in that fuse
[SOURCE: IEC 60050-441:2000, 441-17-37, modified – references to "poles" removed.]
3.1.10
operating time
clearing time
sum of the pre-arcing time and the arcing time
[SOURCE: IEC 60050-441:2000, 441-18-22]
3.1.11
t
I
Joule integral
integral of the square of the current over a given time interval t – t
0 1
t
I t = di t
∫
t
2 2
Note 1 to entry: The pre-arcing I t is the I t integral extended over the pre-arcing time of the fuse.
2 2
Note 2 to entry: The operating I t is the I t integral extended over the operating time of the fuse.
Note 3 to entry: The energy in joules liberated in 1 Ω of resistance in a circuit protected by a fuse is equal to the
2 2
value of the operating I t expressed in A × s.
[SOURCE: IEC 60050-441:2000, 441-18-23]
3.1.12
virtual time
value of Joule integral divided by the square of the value of the prospective current
Note 1 to entry: The values of virtual times usually stated for a fuse-link are the values of pre-arcing time and of
operating time.
[SOURCE: IEC 60050-441:2000, 441-18-37]
3.1.13
time-current characteristic
curve giving the virtual time, for example pre-arcing time or operating time, as a function of
the prospective current under stated conditions of operation
[SOURCE: IEC 60050-441:2000, 441-17-13, modified – "virtual" added.]
3.1.14
cut-off (current) characteristic
let-through (current) characteristic
curve giving the cut-off current as a function of the RMS prospective current, under stated
conditions of operation
Note 1 to entry: The values of the cut-off currents are the maximum values that can be reached whatever the
degree of asymmetry.
[SOURCE: IEC 60050-441:2000, 441-17-14, modified – "RMS" added, and references relating
to direct currents removed from the note to entry.]
IEC 60282-1:2020 © IEC 2020 – 11 –
3.1.15
recovery voltage
voltage which appears across the terminals of a fuse after the breaking of the current
Note 1 to entry: This voltage may be considered in two successive intervals of time, one during which a transient
voltage exists, followed by a second one during which the power frequency recovery voltage alone exists.
[SOURCE: IEC 60050-441:2000, 441-17-25, modified – "a pole of a switching device or"
removed and "or the steady-state" removed from the Note to entry.]
3.1.16
transient recovery voltage
TRV
recovery voltage during the time in which it has a significant transient character
Note 1 to entry: The transient recovery voltage may be oscillatory or non-oscillatory or a combination of these de-
pending on the characteristics of the circuit and the fuse. It includes the voltage shift of the neutral point of a
polyphase circuit.
Note 2 to entry: The transient recovery voltage in three-phase circuits is, unless otherwise stated, that across the
first fuse to clear, because this voltage is generally higher than that which appears across each of the other two
fuses.
[SOURCE: IEC 60050-441:2000, 441-17-26, modified – "switching device" and "pole"
replaced by "fuse" in the Notes to entry.]
3.1.17
power-frequency recovery voltage
recovery voltage after the transient voltage phenomena have subsided
[SOURCE: IEC 60050-441:2000, 441-17-27]
3.1.18
prospective transient recovery voltage (of a circuit)
transient recovery voltage following the breaking of the prospective symmetrical current by an
ideal switching device
Note 1 to entry: The definition assumes that the fuse, for which the prospective transient recovery voltage is
sought, is replaced by an ideal switching device, i.e. having instantaneous transition from zero to infinite
impedance at the very instant of zero current, i.e. at the "natural" zero. For circuits where the current can follow
several different paths, for example a polyphase circuit, the definition further assumes that the breaking of the
current by the ideal switching device takes place only in the pole considered.
[SOURCE: IEC 60050-441:2000, 441-17-29, modified – "switching device or" removed from
note to entry.]
3.1.19
switching voltage
maximum instantaneous value of voltage which appears across the terminals of a fuse during
its operation
Note 1 to entry: The switching voltage may be the arc voltage or may occur during the time of transient recovery
voltage.
[SOURCE: IEC 60050-441:2000, 441-18-31]
3.1.20
minimum breaking current
minimum value of prospective current that a fuse-link is capable of breaking at a stated
voltage under prescribed conditions of use and behaviour
[SOURCE: IEC 60050-441:2000, 441-18-29]
– 12 – IEC 60282-1:2020 © IEC 2020
3.1.21
power dissipation (in a fuse-link)
power released in a fuse-link carrying a stated value of electric current under prescribed
conditions of use and behaviour
Note 1 to entry: Prescribed conditions of use and behaviour generally include a constant RMS value of the
electric current after steady-state temperature conditions are reached.
[SOURCE: IEC 60050-441:2000, 441-18-38]
3.1.22
maximum breaking current
maximum value of prospective current that a fuse-link is capable of breaking at a stated
voltage under prescribed conditions of use and behaviour
3.1.23
lightning impulse
voltage pulse of a specified shape applied during dielectric tests with a virtual front duration of
the order of 1 μs and a time to half value of the order of 50 μs
Note 1 to entry: The lightning impulse is defined by the two figures giving these durations in microseconds; in
particular the standard lightning impulse is 1,2/50 μs.
[SOURCE: IEC 60050-614:2016, 641-03-28]
3.1.24
rated lightning impulse withstand voltage
designated maximum peak withstand-voltage value, of a lightning impulse voltage wave, that
is assigned to the device regarding its ability to withstand a lightning impulse voltage
Note 1 to entry: The term previously used is "basic impulse insulation level (BIL)" (still in common usage).
3.2 Fuses and their component parts
3.2.1
fuse
device that by the fusing of one or more of its specially designed and proportioned
components, opens the circuit to which it is connected by breaking the current when this
exceeds a given value for a sufficient time. The fuse comprises all the parts that form the
complete device
[SOURCE: IEC 60050-441:2000, 441-18-01, modified – "in which it is inserted" changed to "to
which it is connected".]
3.2.2
terminal
conducting part of a fuse provided for an electric connection to external circuits
Note 1 to entry: Terminals may be distinguished according to the kind of circuits for which they are intended (for
example, main terminal, earth terminal, etc.), but also according to their design (for example, screw terminal, plug
terminal, etc.).
3.2.3
fuse-base
fuse-mount
fixed part of a fuse provided with contacts and terminals
Note 1 to entry: The fuse-base comprises all the parts necessary for insulation (see Figure 1).
[SOURCE: IEC 60050-441:2000, 441-18-02, modified – Note 1 to entry added.]
IEC 60282-1:2020 © IEC 2020 – 13 –
Figure 1 – Terminology
3.2.4
fuse-base contact
contact piece of a fuse-base designed to engage with a fuse-link contact (see Figure 1)
[SOURCE: IEC 60050-441:2000, 441-18-03, modified – "corresponding part of the fuse"
replaced with "fuse-link contact (see Figure 1)".]
3.2.5
fuse-link
part of a fuse (including the fuse element(s)) intended to be replaced after the fuse has
operated (see Figure 1)
[SOURCE: IEC 60050-441:2000, 441-18-09, modified – "see Figure 1" added.]
3.2.6
fuse-link contact
contact piece of a fuse-link designed to engage with a fuse-base contact (see Figure 1)
[SOURCE: IEC 60050-441:2000, 441-18-04, modified – "corresponding part of the fuse"
replaced with "fuse-base contact (see Figure 1)".]
3.2.7
fuse-element
part of the fuse-link designed to melt under the action of current exceeding some definite
value for a definite period of time (see Figure 1)
– 14 – IEC 60282-1:2020 © IEC 2020
[SOURCE: IEC 60050-441:2000, 441-18-08 modified – "(see Figure 1)" added.]
3.2.8
indicating device
indicator
part of a fuse provided to indicate whether the fuse has operated (see Figure 1)
[SOURCE: IEC 60050-441:2000, 441-18-17, modified – "(see Figure 1)" added.]
3.2.9
striker
mechanical device forming part of a fuse-link which, when the fuse operates, releases the
energy required to cause operation of other apparatus or indicators or to provide interlocking
[SOURCE: IEC 60050-441:2000, 441-18-18]
3.2.10
thermally operated striker
mechanical device forming part of a fuse-link which, when released by fuse operation or
specific thermal conditions in the fuse-link, releases the energy required to cause operation of
other apparatus or indicators or to provide interlocking
3.3 Additional term
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