SIST EN 62271-107:2006

High-voltage switchgear and controlgear -- Part 107: Alternating current fused circuit-switchers for rated voltages above 1 kV up to and including 52 kV

This part of IEC 62271 applies to three-pole operated units for distribution systems that are functional assemblies of a circuit-switcher and current-limiting fuses designed so as to be capable of: - breaking, at the rated recovery voltage, any load or fault current up to and including the rated short-circuit breaking current; - making, at the rated voltage, circuits to which the rated short-circuit breaking current applies. They are intended to be used for circuits or applications requiring only a normal mechanical and electrical endurance capability. Such applications cover protection of HV/LV transformers for instance, but exclude distribution lines or cables, as well as motor circuits and capacitor bank circuits. Short-circuit conditions with low currents, up to the fused circuit-switcher rated take-over current, are dealt with by supplementary devices (strikers, relays, etc.), properly arranged, tripping the circuit-switcher. Fuses are incorporated in order to ensure that the short-circuit breaking capacity of the device is above that of the circuit-switcher.

Hochspannungs-Schaltgeräte und -Schaltanlagen -- Teil 107: Wechselstrom-Leistungsschalter-Sicherungs-Kombinationen für Bemessungsspannungen über 1 kV bis einschließlich 52 kV

Appareillage à haute tension -- Partie 107: Circuits-switchers fusiblés pour courant alternatif de tension assignée supérieure à 1 kV et jusqu'à 52 kV inclus

La présente partie de la EN 62271 s'applique aux appareils à man uvre tripolaire pour les réseaux de distribution qui sont des ensembles fonctionnels constitués d'un circuit-switcher et de fusibles limiteurs

Visokonapetostne stikalne in krmilne naprave – 107. del: Stikala za izmenični tok z vgrajeno varovalko za naznačene napetosti nad 1kV do vključno 52 kV (IEC 62271-107:2005)

General Information

• Status: Withdrawn
• Publication Date: 30-Nov-2006
• Withdrawal Date: 03-Sep-2012
• ICS: 29.130.10 - High voltage switchgear and controlgear
• Technical Committee: SKA - Switchgear and control gear
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 04-Sep-2012
• Due Date: 27-Sep-2012
• Completion Date: 04-Sep-2012
• Ref Project: EN 62271-107:2005 - High-voltage switchgear and controlgear - Part 107: Alternating current fused circuit-switchers for rated voltages above 1 kV up to and including 52 kV

Relations

• Replaced By: SIST EN 62271-107:2012 - High-voltage switchgear and controlgear - Part 107: Alternating current fused circuit-switchers for rated voltages above 1 kV up to and including 52 kV (IEC 62271-107:2012)
• Effective Date: 28-Jan-2023
• Revised: SIST EN 62271-107:2012 - High-voltage switchgear and controlgear - Part 107: Alternating current fused circuit-switchers for rated voltages above 1 kV up to and including 52 kV (IEC 62271-107:2012)
• Effective Date: 06-May-2014
• Replaced By: SIST EN 62271-107:2012 - High-voltage switchgear and controlgear - Part 107: Alternating current fused circuit-switchers for rated voltages above 1 kV up to and including 52 kV (IEC 62271-107:2012)
• Effective Date: 07-Jun-2022
• Replaced By: SIST EN 62271-107:2012 - High-voltage switchgear and controlgear - Part 107: Alternating current fused circuit-switchers for rated voltages above 1 kV up to and including 52 kV (IEC 62271-107:2012)
• Effective Date: 01-Oct-2012

Standards Content (Sample)

6/29(16., 6,67(1

67$1'$5'
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9LVRNRQDSHWRVWQHVWLNDOQHQDSUDYH±GHO6WLNDOD]DL]PHQLþQLWRN]
YJUDMHQRYDURYDONR]DQD]QDþHQHQDSHWRVWLQDGN9GRYNOMXþQRN9,(&

+LJKYROWDJHVZLWFKJHDUDQGFRQWUROJHDU±3DUW$OWHUQDWLQJFXUUHQWIXVHG
FLUFXLWVZLWFKHUVIRUUDWHGYROWDJHVDERYHN9XSWRDQGLQFOXGLQJN9,(&

,&6 5HIHUHQþQDãWHYLOND

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---------------------- Page: 1 ----------------------

EUROPEAN STANDARD EN 62271-107
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2005

ICS 29.130.10


English version


High-voltage switchgear and controlgear
Part 107: Alternating current fused circuit-switchers for rated voltages
above 1 kV up to and including 52 kV
(IEC 62271-107:2005)


Appareillage à haute tension Hochspannungs-Schaltgeräte und
Partie 107: Circuits-switchers fusiblés -Schaltanlagen
pour courant alternatif de tension Teil 107: Wechselstrom-
assignée supérieure à 1 kV et jusqu'à Leistungsschalter-Sicherungs-
52 kV inclus Kombinationen für
(CEI 62271-107:2005) Bemessungsspannungen über 1 kV
bis einschließlich 52 kV
(IEC 62271-107:2005)



This European Standard was approved by CENELEC on 2005-10-01. 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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and 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


© 2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 62271-107:2005 E

---------------------- Page: 2 ----------------------

EN 62271-107:2005 - 2 -
Foreword
The text of document 17A/732/FDIS, future edition 1 of IEC 62271-107, prepared by SC 17A, High-
voltage switchgear and controlgear, of IEC TC 17, Switchgear and controlgear, was submitted to the
IEC-CENELEC parallel vote and was approved by CENELEC as EN 62271-107 on 2005-10-01.
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) 2006-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2008-10-01
This European Standard should be read in conjunction with EN 60694:1996, to which it refers and
which is applicable, unless otherwise specified. In order to simplify the indication of corresponding
requirements, the same numbering of clauses and subclauses is used as in EN 60694. Additional
subclauses are numbered from 101.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62271-107:2005 was approved by CENELEC as a
European Standard without any modification.
__________

---------------------- Page: 3 ----------------------

- 3 - EN 62271-107:2005
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 Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1)
IEC 60050-441 - International Electrotechnical Vocabulary - -
(IEV)
Chapter 441: Switchgear, controlgear and
fuses

1)
2)
IEC 60265-1 - High-voltage switches EN 60265-1 1998
Part 1: Switches for rated voltages above
1 kV and less than 52 kV

IEC 60282-1 2002 High-voltage fuses EN 60282-1 2002
Part 1: Current-limiting fuses

1)
IEC 60466 - AC insulation-enclosed switchgear and - -
controlgear for rated voltages above 1 kV
and up to and including 38 kV

1) 2)
IEC 60694 - Common specifications for high-voltage EN 60694 1996
switchgear and controlgear standards + corr. May 1999

1)
IEC 60787 - Application guide for the selection of - -
fuse-links of high-voltage fuses for
transformer circuit applications

1) 2)
IEC 62271-100 - High-voltage switchgear and controlgear EN 62271-100 2001
Part 100: High-voltage alternating-current
circuit-breakers

1) 2)
IEC 62271-102 - Part 102: Alternating current EN 62271-102 2002
disconnectors and earthing switches

1) 2)
IEC 62271-105 - Part 105: Alternating current switch-fuse EN 62271-105 2003
combinations

1)
IEC 62271-200 - Part 200: AC metal-enclosed switchgear EN 62271-200 2004
and controlgear for rated voltages above
1 kV and up to and including 52 kV



1)
Undated reference.
2)
Valid edition at date of issue.

---------------------- Page: 4 ----------------------

NORME CEI
INTERNATIONALE
IEC



62271-107
INTERNATIONAL


Première édition
STANDARD

First edition

2005-09


Appareillage à haute tension –
Partie 107:
Circuits-switchers fusiblés pour courant alternatif
de tension assignée supérieure à 1 kV et jusqu'à
52 kV inclus

High-voltage switchgear and controlgear –
Part 107:
Alternating current fused circuit-switchers
for rated voltages above 1 kV up to and
including 52 kV

 IEC 2005 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
CODE PRIX
X
PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

---------------------- Page: 5 ----------------------

62271-107  IEC:2005 – 3 –
CONTENTS
FOREWORD.9
1 General .13
1.1 Scope.13
1.2 Normative references .13
2 Normal and special service conditions .15
3 Terms and definitions .15
3.1 General terms .15
3.2 Assemblies of switchgear and controlgear .15
3.3 Parts of assemblies .15
3.4 Switching devices.17
3.5 Parts of switchgear and controlgear .17
3.6 Operation .17
3.7 Characteristic quantities .17
4 Ratings.21
4.1 Rated voltage (U ).21
r
4.2 Rated insulation level .21
4.3 Rated frequency (f ) .21
r
4.4 Rated normal current and temperature rise.21
4.5 Rated short-time withstand current (I ).23
k
4.6 Rated peak withstand current (I ).23
p
4.7 Rated duration of short circuit (t ) .23
k
4.8 Rated supply voltage of closing and opening devices and of auxiliary and
control circuits (U ) .23
a
4.9 Rated supply frequency of closing and opening devices and of auxiliary circuits .23
4.10 Rated pressure of compressed gas supply for insulation and/or operation.23
5 Design and construction .25
5.1 Requirements for liquids in fused circuit-switchers .25
5.2 Requirements for gases in fused circuit-switchers .25
5.3 Earthing of fused circuit-switchers .25
5.4 Auxiliary and control equipment.25
5.5 Dependent power operation.27
5.6 Stored energy operation .27
5.7 Independent manual operation .27
5.8 Operation of releases .27
5.9 Low- and high- pressure interlocking and monitoring devices .27
5.10 Nameplates .27
5.11 Interlocking devices.29
5.12 Position indication .29
5.13 Degrees of protection by enclosures.29
5.14 Creepage distances.29
5.15 Gas and vacuum tightness .29
5.16 Liquid tightness .29
5.17 Flammability.29
5.18 Electromagnetic compatibility (EMC) .29

---------------------- Page: 6 ----------------------

62271-107  IEC:2005 – 5 –
6 Type tests .31
6.1 General .31
6.2 Dielectric tests .33
6.3 Radio interference voltage (RIV) tests .33
6.4 Measurement of the resistance of circuits.33
6.5 Temperature-rise tests .33
6.6 Short-time withstand current and peak withstand current tests .35
6.7 Verification of the protection.35
6.8 Tightness tests .35
6.9 Electromagnetic compatibility tests (EMC).35
7 Routine tests .51
8 Guide for the selection of fused circuit-switchers .53
8.1 Objective.53
8.2 Short-circuit breaking current .53
8.3 Rated maximum thermal current.55
8.4 Currents between thermal current and I of the fuses .55
3
8.5 Transfer current .55
8.6 Take-over current.55
8.7 Extension of the validity of type tests .55
8.8 Operation .57
8.9 Comparison of performances of fused circuit-switchers with performances of
switch-fuse combinations and circuit-breakers.59
9 Information to be given with enquiries, tenders and orders .61
9.1 Information to be given with enquiries and orders.61
9.2 Information to be given with tenders .61
10 Rules for transport, storage, installation, operation and maintenance .61
11 Safety.61

Annex A (informative) Applicability of the rated take-over current test duty .73

Bibliography.89

Figure 1 – Representation of a specified TRV by a two-parameter reference line and a
delay line .63
Figure 2 – Example of a two-parameter reference line for a TRV .63
Figure 3 – Arrangement of test circuits for test duties TD , TD ,TD and TD .65
Ith Isc Ito Ilow
Figure 4 – Measurement of the power frequency recovery voltage with striker operation.67
Figure 5 – Characteristics for determining the take-over current .69
Figure A.1 – Visualization of the application margin for a given fuse .77

---------------------- Page: 7 ----------------------

62271-107  IEC:2005 – 7 –
Table 1 – Nameplate markings.27
Table 2 – Comparison between switch-fuse combination and fused circuit-switcher .59
Table 3 – Comparison between fused circuit-switcher and circuit breaker .59
Table 4 – Summary of test parameters for test duties .71
Table A.1 – Minimum application margin according to fuse characteristic .83
Table A.2 – Minimum protection time delay.85
Table A.3 – Examples of possible need for time delay .87

---------------------- Page: 8 ----------------------

62271-107  IEC:2005 – 9 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 107: Alternating current fused circuit-switchers
for rated voltages above 1 kV up to and including 52 kV


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 62271-107 has been prepared by subcommittee 17A: High voltage
switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.
The text of this standard is based on the following documents:
FDIS Report on voting
17A/732/FDIS 17A/739/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

---------------------- Page: 9 ----------------------

62271-107  IEC:2005 – 11 –
This standard should be read in conjunction with IEC 60694, second edition, published in
1996, to which it refers and which is applicable, unless otherwise specified. In order to
simplify the indication of corresponding requirements, the same numbering of clauses and
subclauses is used as in IEC 60694. Amendments to these clauses and subclauses are given
under the same numbering, whilst additional subclauses are numbered from 101.
The list of other parts of the IEC 62271 series can be found on the IEC website.
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.

---------------------- Page: 10 ----------------------

62271-107  IEC:2005 – 13 –
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 107: Alternating current fused circuit-switchers
for rated voltages above 1 kV up to and including 52 kV



1 General
1.1 Scope
This part of IEC 62271 applies to three-pole operated units for distribution systems that are
functional assemblies of a circuit-switcher and current-limiting fuses designed so as to be
capable of:
– breaking, at the rated recovery voltage, any load or fault current up to and including the
rated short-circuit breaking current;
– making, at the rated voltage, circuits to which the rated short-circuit breaking current
applies.
They are intended to be used for circuits or applications requiring only a normal mechanical
and electrical endurance capability. Such applications cover protection of HV/LV transformers
for instance, but exclude distribution lines or cables, as well as motor circuits and capacitor
bank circuits.
Short-circuit conditions with low currents, up to the fused circuit-switcher rated take-over
current, are dealt with by supplementary devices (strikers, relays, etc.), properly arranged,
tripping the circuit-switcher. Fuses are incorporated in order to ensure that the short-circuit
breaking capacity of the device is above that of the circuit-switcher.
NOTE 1 In this standard the term "fuse" is used to designate either the fuse or the fuse-link where the general
meaning of the text does not result in ambiguity.
This standard applies to fused circuit-switchers designed with rated voltages above 1 kV up to
and including 52 kV for use on three-phase alternating current systems of either 50 Hz or
60 Hz. Comparison with other existing switching devices is provided in Clause 8.
NOTE 2 Other circuit-switchers exist; see reference [1] of the bibliography.
Fuses are covered by IEC 60282-1.
Earthing switches forming an integral part of a circuit-switcher are covered by IEC 62271-102.
Installation in enclosure, if any, is covered either by IEC 62271-200 or by IEC 60466.
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.

---------------------- Page: 11 ----------------------

62271-107  IEC:2005 – 15 –
IEC 60050(441), International Electrotechnical Vocabulary (IEV) – Chapter 441: Switchgear,
controlgear and fuses
IEC 60265-1: High-voltage switches – Part 1: Switches for rated voltages above 1 kV and less
than 52 kV
IEC 60282-1: 2002, High-voltage fuses – Part 1: Current-limiting fuses
IEC 60466: A.C. insulation-enclosed switchgear and controlgear for rated voltages above 1 kV
and up to and including 38 kV
IEC 60694: Common specifications for high-voltage switchgear and controlgear standards
IEC 60787: Application guide for the selection of fuse-links of high-voltage fuses for
transformer circuit applications
IEC 62271-100: High-voltage switchgear and controlgear – Part 100: High-voltage alternating-
current circuit-breakers
IEC 62271-102: High-voltage switchgear and controlgear – Part 102: Alternating current
disconnectors and earthing switches
IEC 62271-105: High-voltage switchgear and controlgear – Part 105: Alternating current
switch-fuse combinations
IEC 62271-200: High-voltage switchgear and controlgear – Part 200: A.C. metal-enclosed
switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV
2 Normal and special service conditions
Clause 2 of IEC 60694 is applicable.
3 Terms and definitions
For the purposes of this document, the terms and definitions of IEC 60050(441) and
IEC 60694 apply. Some of them are recalled here for ease of reference.
The definitions given below are also applicable. Additional definitions are classified so as to
be aligned with the classification used in IEC 60050(441). The definitions of IEC 60050(441)
are not repeated but reference is made to their specific number.
3.1 General terms
None
3.2 Assemblies of switchgear and controlgear
None.
3.3 Parts of assemblies
None.

---------------------- Page: 12 ----------------------

62271-107  IEC:2005 – 17 –
3.4 Switching devices
3.4.101
circuit-switcher
mechanical switching device suitable for making, carrying and interrupting currents under
normal circuit conditions. It is also suitable for interrupting specified fault currents that may be
less than its short-time withstand current.
NOTE Other circuit-switchers exist; see reference [1] of the bibliography.
3.4.102
fused circuit-switcher
device comprising a three-pole circuit-switcher and three current limiting fuses, capable of
making and breaking any load or fault current up to its short-circuit breaking current, under
TRV and power factor conditions defined in this standard
3.4.103
fused circuit-switcher base (or device base)
fused circuit-switcher without fuse-links mounted
3.4.104
non-sustained disruptive discharge (NSDD)
disruptive discharge associated with current interruption, that does not result in the
resumption of power frequency current or, in the case of capacitive current interruption does
not result in current at the natural frequency of the circuit
3.5 Parts of switchgear and controlgear
3.5.101
release
[IEV 441-15-17]
3.5.102
over-current release
[IEV 441-16-33]
3.5.103
shunt release
[IEV 441-16-41]
3.6 Operation
3.6.101
independent manual operation (of the fused circuit-switcher)
[IEV 441-16-16]
3.6.102
stored energy operation (of the fused circuit-switcher)
[IEV 441-16-15]
3.7 Characteristic quantities
3.7.101
prospective current (of a circuit and with respect to a switching device or a fuse)
[IEV 441-17-01]

---------------------- Page: 13 ----------------------

62271-107  IEC:2005 – 19 –
3.7.102
prospective peak current
[IEV 441-17-02]
3.7.103
maximum prospective peak current
[IEV 441-17-04]
3.7.104
prospective breaking current
[IEV 441-17-06]
3.7.105
breaking current
[IEV 441-17-07]
3.7.106
minimum breaking current
[IEV 441-18-29]
3.7.107
short-circuit making capacity
[IEV 441-17-10]
3.7.108
take-over current
[IEV 441-17-16]
3.7.109
thermal current
I
th
maximum current carried continuously without the temperature rise of the various parts
exceeding the limits specified
3.7.110
fused short-circuit current
[IEV 441-17-21]
3.7.111
applied voltage
[IEV 441-17-24]
3.7.112
recovery voltage
[IEV 441-17-25]
3.7.113
transient recovery voltage (TRV)
[IEV 441-17-26]
3.7.114
power frequency recovery voltage
[IEV 441-17-27]
3.7.115
prospective transient recovery voltage
[IEV 441-17-29]
3.7.116
minimum opening time (of the fused circuit-switcher)
minimum interval of time between the initiation of the opening, from an external source, and
the first instant of the separation of the arcing contacts in any one pole

---------------------- Page: 14 ----------------------

62271-107  IEC:2005 – 21 –
3.7.117
fuse-initiated opening time (of a fused circuit-switcher)
time taken from the instant at which arcing in the fuse commences to the i
...