SIST EN 60077-5:2004
(Main)Railway applications - Electrotechnical equipment for rolling stock -- Part 5: Electrotechnical components - Rules for HV fuses
Railway applications - Electrotechnical equipment for rolling stock -- Part 5: Electrotechnical components - Rules for HV fuses
Gives additional or amended rules for high voltage fuses as a supplement to those given by EN 60077-2. States specifically the characteristics of the fuses, their service conditions, the tests to be performed, and the markings.
Bahnanwendungen - Elektrische Betriebsmittel auf Bahnfahrzeugen -- Teil 5: Elektrotechnische Bauteile - Regeln für Hochspannungssicherungen
Applications ferroviaires - Equipements électriques du matériel roulant -- Partie 5: Composants électrotechniques - Règles pour les fusibles à haute tension
Fournit des prescriptions complémentaires ou modifiées pour les fusibles à haute tension en supplément à celles données dans la EN 60077-2. Définit spécifiquement les caractéristiques des fusibles, leurs conditions de service, les essais à effectuer, et les marquages.
Železniške naprave – Elektrotehnična oprema za vozna sredstva – 5. del: Elektrotehnične komponente – Pravila za visokonapetostne varovalke (IEC 60077- 5:2003)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 60077-5:2004
01-september-2004
äHOH]QLãNHQDSUDYH±(OHNWURWHKQLþQDRSUHPD]DYR]QDVUHGVWYD±GHO
(OHNWURWHKQLþQHNRPSRQHQWH±3UDYLOD]DYLVRNRQDSHWRVWQHYDURYDONH ,(&
Railway applications - Electrotechnical equipment for rolling stock -- Part 5:
Electrotechnical components - Rules for HV fuses
Bahnanwendungen - Elektrische Betriebsmittel auf Bahnfahrzeugen -- Teil 5:
Elektrotechnische Bauteile - Regeln für Hochspannungssicherungen
Applications ferroviaires - Equipements électriques du matériel roulant -- Partie 5:
Composants électrotechniques - Règles pour les fusibles à haute tension
Ta slovenski standard je istoveten z: EN 60077-5:2003
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
29.280 (OHNWULþQDYOHþQDRSUHPD Electric traction equipment
SIST EN 60077-5:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD EN 60077-5
NORME EUROPÉENNE
EUROPÄISCHE NORM September 2003
ICS 45.060
English version
Railway applications -
Electrotechnical equipment for rolling stock
Part 5: Electrotechnical components -
Rules for HV fuses
(IEC 60077-5:2003)
Applications ferroviaires - Bahnanwendungen -
Equipements électriques Elektrische Betriebsmittel
du matériel roulant auf Bahnfahrzeugen
Partie 5: Composants électrotechniques - Teil 5: Elektrotechnische Bauteile -
Règles pour les fusibles à haute tension Regeln für Hochspannungssicherungen
(CEI 60077-5:2003) (IEC 60077-5:2003)
This European Standard was approved by CENELEC on 2003-09-01. 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, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, 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
© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60077-5:2003 E
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EN 60077-5:2003 - 2 -
Foreword
The text of document 9/752/FDIS, future edition 1 of IEC 60077-5, prepared by IEC TC 9, Electrical
equipment and systems for railways, was submitted to the IEC-CENELEC parallel vote and was
approved by CENELEC as EN 60077-5 on 2003-09-01.
This standard should be read in conjunction with EN 60077-1:2002 and EN 60077-2:2002.
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) 2004-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2006-09-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annexes A and ZA are normative and annexes B to D are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60077-5:2003 was approved by CENELEC as a European
Standard without any modification.
__________
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- 3 - EN 60077-5:2003
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
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
IEC 60050-441 1984 International Electrotechnical - -
Vocabulary (IEV)
Chapter 441: Switchgear, controlgear
and fuses
IEC 60050-811 1991 Chapter 811: Electric traction - -
IEC 60077-1 1999 Railway applications - Electric EN 60077-1 2002
(mod) equipment for rolling stock
Part 1: General service conditions and
general rules
IEC 60077-2 1999 Part 2: Electrotechnical components - EN 60077-2 2002
(mod) General rules
IEC 60269-1 1998 Low-voltage fuses EN 60269-1 1998
Part 1: General requirements
IEC 60282-1 2002 High-voltage fuses EN 60282-1 2002
Part 1: Current-limiting fuses
IEC 60850 2000 Railway applications - Supply voltages - -
of traction systems
IEC 61373 1999 Railway applications - Rolling stock EN 61373 1999
equipment - Shock and vibration tests
ISO 3 1973 Preferred numbers - Series of preferred - -
numbers
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NORME
CEI
INTERNATIONALE IEC
60077-5
INTERNATIONAL
Première édition
STANDARD
First edition
2003-07
Applications ferroviaires –
Equipements électriques du matériel roulant –
Partie 5:
Composants électrotechniques –
Règles pour les fusibles à haute tension
Railway applications –
Electric equipment for rolling stock –
Part 5:
Electrotechnical components –
Rules for HV fuses
© IEC 2003 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: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
U
Commission Electrotechnique Internationale PRICE CODE
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
Pour prix, voir catalogue en vigueur
For price, see current catalogue
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60077-5 © IEC:2003 – 3 –
CONTENTS
FOREWORD . 7
1 Scope and object .11
2 Normative references.11
3 Definitions.13
3.1 Components .13
3.2 Operational characteristics.15
4 Classification .19
4.1 Breaking range (see also Annex B) .19
4.2 Utilisation category.19
5 Characteristics.19
6 Product information.21
6.1 Documentation.21
6.2 Marking .21
7 Normal service conditions .21
8 Constructional and performance requirements.23
8.1 Constructional requirements.23
8.2 Performance requirements .23
9 Tests .27
9.1 Kinds of tests.27
9.2 Tests for the verification of constructional requirements .29
9.3 Type tests for the verification of performance requirements .29
9.4 Routine tests for the verification of performance requirements.45
Annex A (normative) Connection diagram for temperature-rise tests .47
Annex B (informative) Comparison between “a” and “g” fuse time current characteristics .49
Annex C (informative) Diagram of the test circuit for breaking capacity tests .51
Annex D (informative) Verification of breaking capacity.53
Figure A.1 – Connection diagram for temperature-rise tests .47
Figure B.1 – Comparison between “a” and “g” fuse time current characteristics .49
Figure C.1 – Diagram of the test circuit for breaking capacity tests.51
Figure D.1 – Test circuit calibration.53
Figure D.2 – Breaking operation when the instant of arc initiation is after the peak value
of the current.55
Figure D.3 – Breaking operation when the instant of arc initiation is prior to the peak
value of the current .55
Table 1 – Conventional times for “g” fuse-links .21
Table 2 – Rated and test voltages for d.c. fuse-links supplied from the contact line .25
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60077-5 © IEC:2003 – 5 –
Table 3 – Sequence of tests for the highest rating of a homogenous series .31
Table 4 – Sequence of tests for the lowest rating of a homogenous series .33
Table 5 – Sequence of tests for intermediate ratings of a homogenous series .35
Table 6 – Tolerances on test values .35
Table 7 – Parameters for breaking capacity tests of d.c. fuse-links.39
Table 8 – Time constant of the test circuit.41
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60077-5 © IEC:2003 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
RAILWAY APPLICATIONS –
ELECTRIC EQUIPMENT FOR ROLLING STOCK –
Part 5: Electrotechnical components –
Rules for HV 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, 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 60077-5 has been prepared by IEC technical committee 9: Electrical
equipment and systems for railways.
This standard shall be read in conjunction with IEC 60077-1 and IEC 60077-2.
The text of this standard is based on the following documents:
FDIS Report on voting
9/752/FDIS 9/762/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.
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60077-5 © IEC:2003 – 9 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 60077 consists of the following parts under the general title Railway applications – Electric
equipment for rolling stock:
Part 1 – General service conditions and general rules
Part 2 – Electrotechnical components – General rules
Part 3 – Electrotechnical components – Rules for d.c. circuit-breakers
Part 4 – Electrotechnical components – Rules for a.c. circuit-breakers
Part 5 – Electrotechnical components – Rules for HV fuses
The committee has decided that the contents of this publication will remain unchanged until 2011.
At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
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60077-5 © IEC:2003 – 11 –
RAILWAY APPLICATIONS –
ELECTRIC EQUIPMENT FOR ROLLING STOCK –
Part 5: Electrotechnical components –
Rules for HV fuses
1 Scopeand object
The purpose of this part of IEC 60077 is to give additional or amended rules for high voltage
fuses as a supplement to those given by IEC 60077-2.
NOTE In this product standard the term high voltage fuses is used in the context of the voltages used in the field
of railway rolling stock.
The high voltage fuses concerned are those to be connected into power and/or auxiliary
circuits. The nominal voltage of these circuits lies between 600 V d.c. and 3 000 V d.c.,
according to IEC 60850. These fuses may also be used in auxiliary a.c. circuits up to a nominal
voltage of 1 500 V.
NOTE Certain of these rules may, after agreement between user and manufacturer, be used for fuses installed on
vehicles other than rail rolling stock such as mine locomotives, trolleybuses, etc.
This product standard together with IEC 60077-2 states specifically:
a) the characteristics of the fuses;
b) the service conditions with which the fuses have to comply with reference to:
– operation and behaviour in normal service;
– operation and behaviour in case of short circuit;
– dielectric properties.
c) the tests intended for confirming the compliance of the fuse with the characteristics under
the service conditions and the methods to be adopted for these tests;
d) the information to be marked on, or given with, the fuse.
This standard does not cover parallel connection of fuses.
During preparation of this product standard, IEC 60269-1 and IEC 60282-1 have been
considered and their requirements have been kept as far as possible.
This product standard makes reference to the general rules for electrotechnical components
given in IEC 60077-2, but for general conditions reference is made directly to IEC 60077-1.
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.
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60077-5 © IEC:2003 – 13 –
IEC 60050(441):1984, International Electrotechnical Vocabulary (IEV) – Chapter 441: Switch-
gear, controlgear and fuses
IEC 60050(811):1991, International Electrotechnical Vocabulary (IEV) – Chapter 811: Electric
traction
IEC 60077-1:1999, Railway applications – Electric equipment for rolling stock – Part 1: General
service conditions and general rules
IEC 60077-2:1999, Railway applications – Electric equipment for rolling stock – Part 2:
Electrotechnical components – General rules
IEC 60269-1:1998, Low-voltage fuses – Part 1: General requirements
IEC 60282-1:2002, High-voltage fuses – Part 1: Current – limiting fuses
IEC 60850:2000, Railway applications – Supply voltages of traction systems
IEC 61373:1999, Railway applications – Rolling stock equipment – Shock and vibration tests
ISO 3:1973, Preferred numbers – Series of preferred numbers
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60077-1 and
IEC 60077-2 together with the following definitions apply.
3.1 Components
3.1.1
fuse
device that, by the fusing of one or more of its specifically designed and proportioned
components, opens the circuit in which it is inserted 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.
[IEV 441-18-01]
3.1.2
fuse-link
part of a fuse (including the fuse-element(s)) intended to be replaced after the fuse has
operated
[IEV 441-18-09]
3.1.3
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
[IEV 441-18-08]
3.1.4
fuse-base
fixed part of a fuse provided with contacts and terminals
[IEV 441-18-02]
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60077-5 © IEC:2003 – 15 –
3.1.5
indicating device
part of a fuse provided to indicate whether the fuse has operated
[IEV 441-18-17]
3.2 Operational characteristics
3.2.1
prospective current
current that would flow in the circuit if the fuse were replaced by a conductor of negligible
impedance
[IEV 441-17-01, modified]
3.2.2
prospective peak current
peak value of a prospective current during the transient period following fault current initiation
[IEV 441-17-02, modified]
NOTE This term is commonly associated with short-circuit conditions.
3.2.3
pre-arcing time
interval of time between the beginning of a current large enough to cause a break in the fuse-
elements and the instant when an arc is initiated
[IEV 441-18-21]
3.2.4
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
[IEV 441-17-37, modified]
3.2.5
operating time
sum of the pre-arcing time and the arcing time
[IEV 441-18-22]
3.2.6
arc voltage
instantaneous value of voltage which appears across the terminals of a fuse during the arcing
time
[IEV 441-18-30]
3.2.7
peak arc voltage
maximum instantaneous value of voltage which under prescribed conditions appears across
the terminals of a fuse during the arcing time
[IEV 441-17-30, modified]
NOTE After extinction of the arc, an overvoltage (transient recovery voltage) may be present across the terminals.
The value of this will depend on the circuit characteristics and the fuse. This overvoltage is not part of the peak arc
voltage (see Figures D.2 and D.3).
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60077-5 © IEC:2003 – 17 –
3.2.8
d.c. or power frequency steady-state recovery voltage
recovery voltage in a circuit after the transient voltage phenomena have subsided, expressed
by the mean value where ripple is present
[IEV 441-17-28, modified]
NOTE This is shown as B and B in Figures D.2 and D.3.
1 2
3.2.9
peak let-through current
maximum instantaneous value of current attained during the operation of a fuse
[IEV 441-17-12, modified]
3.2.10
2
I t; Joule integral
integral of the square of the current over a given time interval
[IEV 441-18-23]
t
1
22
It = i dt
³
t
0
2 2
NOTE 1 The pre-arcing I t is the I t integral extended over the pre-arcing time of the fuse.
2 2
NOTE 2 The operating I t is the I t integral extended over the operating time of the fuse.
NOTE 3 The energy in joules liberated in one ohm 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.
3.2.11
time-current characteristic
curve giving the time, e.g. pre-arcing time or operating time, as a function of the prospective
current under stated conditions of operation
[IEV 441-17-13]
3.2.12
conventional non-fusing current
value of current specified as that which the fuse-link is capable of carrying for a specified time
(conventional time) without melting
[IEV 441-18-27]
3.2.13
conventional fusing current
value of current specified as that which causes operation of the fuse-link within a specified time
(conventional time)
[IEV 441-18-28]
3.2.14
rated value
quantity value, generally assigned by a manufacturer, for a specified operating condition of a fuse
[IEV 811-11-02, modified]
NOTE The rated values usually stated for fuses are voltage, current, breaking capacity and power dissipation.
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60077-5 © IEC:2003 – 19 –
4 Classification
4.1 Breaking range (see also Annex B)
Fuse-links are classified according to whether they are:
“g” fuse-link – with a full range breaking capacity, i.e. capable under specified conditions of
breaking all currents which cause melting of the fuse-element up to its rated breaking capacity;
“a” fuse-link – with a partial range breaking capacity, i.e. capable of breaking under specified
conditions all currents between their minimum breaking capacity and their rated breaking
capacity. They may be used in conjunction with another switching device where protection is
required against over-currents below their minimum breaking capacity.
NOTE Examples of “a” fuse-link protection may be those for protection of semi-conductor devices, motors, etc.
4.2 Utilisation category
Fuse-links may be categorised according to whether they are to be subjected in normal service
to:
– current values which do not exceed their continuous rating;
– current values which briefly exceed their continuous rating on a regular basis, such as when
starting a rotating machine;
– current values which do not exceed their continuous rating but which are switched or
change significantly in a frequently repeated pattern;
or they have to provide a special protection as, for example:
– semi-conductor conditions, where fast action is required in order to limit the peak let-
2
through current and the operating I t;
– provide a time delayed operation.
5 Characteristics
The characteristics of a fuse shall be stated in terms of the following:
– rated voltage(s) d.c. and/or a.c.;
– rated current (I );
n
– rated frequency;
– rated breaking capacity;
– breaking range;
– rated power dissipation;
– time-current characteristics. The conventional times and currents for “g” fuse-links are
given in Table 1;
– overload capability;
2 2 2
– I t characteristics (minimum pre-arcing I t and maximum operating I t);
– peak let-through current related to prospective current and time constant;
– current rating correction factors versus ambient temperature;
– peak arc voltage related to operating voltage;
– rated insulation voltage for fuse-bases.
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60077-5 © IEC:2003 – 21 –
2
When presented graphically, the I t characteristics shall be given with prospective current as
2
abscissa and I t values as ordinate. Logarithmic scales shall be used on both co-ordinate
axes.
Table 1 – Conventional times for “g” fuse-links
Specified time
Rated current
(conventional time)
A
h
I ≤ 63 1
n
2
63 < I ≤ 160
n
3
160 < I ≤ 400
n
4
I > 400
n
6 Product information
6.1 Documentation
This information shall be given in the manufacturer's catalogue or manual.
Subclause 6.1 of IEC 60077-2 applies, supplemented by the following:
– rated voltage;
– rated current;
– rated breaking capacity and time constant;
– suitable applications – see 4.2;
2 2 2
– I t characteristics (minimum pre-arcing I t and maximum operating I t);
– correction factors for current rating versus ambient temperature, varying load and overload;
– physical dimensions;
– special instructions for storage, installation, maintenance, if applicable.
6.2 Marking
Fuse-links and fuse-bases shall possess durable and legible nameplates or engraved markings
in accordance with 6.2 of IEC 60077-2.
The markings of the fuse-link and fuse-base shall include the following data:
– manufacturer's name or trade mark;
– manufacturer's type designation;
– rated voltage (d.c. and/or a.c.);
– rated current.
7 Normal service conditions
These conditions are given in Clause 7 of IEC 60077-1.
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60077-5 © IEC:2003 – 23 –
8 Constructional and performance requirements
8.1 Constructional requirements
In addition to the requirements of 8.1 of IEC 60077-2, the fuse shall comply with the following
requirements.
8.1.1 Fuse-link
The fuse-link shall be sufficiently robust so that there shall be no damage to the surroundings
e.g. by permanent arcing, flashover or any ejection of flames or materials during operation.
It shall be possible to replace the fuse-links easily.
NOTE For further details, see 8.5.8. of IEC 60269-1.
8.1.2 Fuse-base
The fuse-base shall incorporate contacts which ensure that the connections to the fuse-link are
adequate under all conditions of thermal cycling, vibration and shock during normal service and
during the application of the electro-dynamic forces when the fuse-link is rupturing overload or
short-circuit currents up to its rated breaking capacity value.
8.1.3 Spring-loaded contacts
Where the fuse-base incorporates spring-loaded contacts for electrical connection and
mechanical retention of the fuse-link, these contacts shall withstand 100 cycles of insertions
and removals of the fuse-link without deterioration of the electrical and mechanical properties.
8.1.4 External terminals
Terminals for external connection to the fuse-base shall provide a constant clamping force
unaffected by variation in current through them. They shall be capable of enduring multiple
connection and disconnection of the external conductors without deterioration. Terminal screw
thread shall have a minimum size of M5.
Terminals shall be such that they cannot turn or be displaced when the connecting screws are
tightened, and such that the conductors cannot be displaced.
The parts gripping the conductors shall be of metal and shall have a shape such that
...
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