SIST EN 50355:2014
(Main)Railway applications - Railway rolling stock cables having special fire performance - Guide to use
Railway applications - Railway rolling stock cables having special fire performance - Guide to use
This European Standard gives guidance on the safe use of rolling stock cables specified in EN 50264, EN 50306 and EN 50382.These cables will only be used for the wiring of railway rolling stock and within the limits given in the manner described in this European Standard. All these cables are for fixed installation where there is no free movement of cable, except for stresses due to typical service. This European Standard will be applied in conjunction with the relevant product and installation standards. Stricter requirements than those given in this standard could be necessary; see in particular EN 50343.
Bahnanwendungen - Kabel und Leitungen für Schienenfahrzeuge mit verbessertem Verhalten im Brandfall - Leitfaden für die Verwendung
Applications ferroviaires - Câbles à comportement au feu spécifié pour matériel roulant ferroviaire - Guide d'emploi
La présente Norme européenne donne des lignes directrices pour l'utilisation en toute sécurité des câbles pour matériel roulant spécifiés dans les EN 50264, EN 50306 et EN 50382. Ces câbles sont uniquement utilisés pour le câblage du matériel roulant ferroviaire et dans les limites données de la manière décrite dans la présente Norme européenne. Tous ces câbles sont destinés à une installation fixe dans laquelle il n'y a aucun déplacement libre du câble, à l’exception de celui lié aux contraintes dues au fonctionnement normal. La présente Norme européenne est appliquée conjointement avec les normes pertinentes de produit et d'installation. Des exigences plus strictes que celles données dans cette norme pourraient être nécessaires ; voir en particulier l'EN 50343. Cette Norme européenne n'est pas applicable aux: – câbles de liaison inter-rames; – câbles soumis à des flexions continuelles; – câbles des pantographes; – câbles coaxiaux, de données et à fibres optiques; – faisceaux de fils; – câbles prévus pour des tensions supérieures à 3,6/6 kV; – applications autres que le câblage du matériel roulant ferroviaire; – câbles nécessitant l'intégrité des circuits. Les exigences légales ou réglementaires sont prioritaires par rapport aux lignes directrices données dans ce document. En l'absence de lignes directrices ou bien si celles-ci ne peuvent pas être déduites des informations générales, il est recommandé de demander conseil au fabricant du câble.
Železniške naprave - Kabli (in ožičenje) s posebno požarno odpornostjo v železniških vozilih - Vodilo za uporabo
Ta evropski standard vsebuje navodila o varni uporabi kablov v železniških vozilih iz standardov EN 50264, EN 50306 in EN 50382. Ti kabli se uporabljajo le za ožičenje železniških vozil in v okviru omejitev, ki so opisane v tem evropskem standardu. Vsi taki kabli so namenjeni stalni napeljavi brez prostega gibanja kablov z izjemo obremenitev, ki jih prinaša običajna uporaba. Ta evropski standard se uporablja v povezavi z ustreznim izdelkom in standardi namestitve. Morda so potrebne strožje zahteve od teh, ki so navedene v tem standardu; glej zlasti standard EN 50343.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 50355:2014
01-maj-2014
1DGRPHãþD
SIST EN 50355:2004
äHOH]QLãNHQDSUDYH.DEOL LQRåLþHQMH VSRVHEQRSRåDUQRRGSRUQRVWMRY
åHOH]QLãNLKYR]LOLK9RGLOR]DXSRUDER
Railway applications - Railway rolling stock cables having special fire performance -
Guide to use
Bahnanwendungen - Kabel und Leitungen für Schienenfahrzeuge mit verbessertem
Verhalten im Brandfall - Leitfaden für die Verwendung
Applications ferroviaires - Câbles à comportement au feu spécifié pour matériel roulant
ferroviaire - Guide d'emploi
Ta slovenski standard je istoveten z: EN 50355:2013
ICS:
13.220.20 3RåDUQD]DãþLWD Fire protection
29.060.20 Kabli Cables
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
SIST EN 50355:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN 50355:2014
---------------------- Page: 2 ----------------------
SIST EN 50355:2014
EUROPEAN STANDARD
EN 50355
NORME EUROPÉENNE
August 2013
EUROPÄISCHE NORM
ICS 13.220.20; 29.060.20; 45.060.01 Supersedes EN 50355:2003
English version
Railway applications -
Railway rolling stock cables having special fire performance -
Guide to use
Applications ferroviaires - Bahnanwendungen -
Câbles à comportement au feu spécifié Kabel und Leitungen für
pour matériel roulant ferroviaire - Schienenfahrzeuge mit verbessertem
Guide d'emploi Verhalten im Brandfall -
Leitfaden für die Verwendung
This European Standard was approved by CENELEC on 2013-07-01. 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 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, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50355:2013 E
---------------------- Page: 3 ----------------------
SIST EN 50355:2014
EN 50355:2013 (E) - 2 -
CONTENTS
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms, definitions and abbreviations.7
4 Requirements for safety .7
5 Fire . 10
6 Limiting conditions . 11
7 Cable designation . 16
8 Initial and periodic inspections . 16
9 Electrical test after installation. 16
Annex A (informative) Recommended current ratings for railway rolling stock cables . 31
Annex B (informative) Recommended short-circuit current ratings for rolling stock
cables of 90 °C maximum conductor temperature . 34
Bibliography . 36
Figure 1 — Definition of internal bending radius . 15
Table 1 - Properties Available .9
Table 2 - Voltages . 11
Table 3 - Temperature for expected lifetime according to reference standard . 14
Table 4 - Single-core cables Standard wall EN 50264-2-1 and reduced wall EN 50264-
3-1 18
Table 5 - Single-core cables Use conditions Standard wall EN 50264-2-1 and reduced
wall EN 50264-3-1 . 19
Table 6 - Multicore cables Standard wall EN 50264-2-2 and reduced wall EN 50264-3-2 . 20
Table 7 - Multicore cables Use conditions Standard wall EN 50264-2-2 and reduced
wall EN 50264-3-2 . 21
Table 8 - Single-core cables EN 50382-2 . 22
Table 9 - Single-core cables Use conditions EN 50382-2 . 23
Table 10 - Single-core cables Thin wall insulation, thin wall sheathed EN 50306-2 and -
3 24
Table 11 - Single-core cables Use conditions Thin wall insulation, thin wall sheathed
EN 50306-2 and -3 . 25
Table 12 - Multicore cables (pairs, triples and quads) Thin wall insulation, thin wall
sheathed EN 50306-3 . 26
Table 13 - Multicore cables (pairs, triples and quads) Use conditions Thin wall
insulation, thin wall sheathed EN 50306-3 . 27
Table 14 - Multicore and Multipair cables Thin wall insulation, Standard wall sheathed
EN 50306-4 . 28
Table 15 - Multicore and Multipair cables Use conditions Thin wall insulation, Standard
wall sheathed EN 50306-4 . 29
---------------------- Page: 4 ----------------------
SIST EN 50355:2014
- 3 - EN 50355:2013 (E)
Table 16 - Minimum bending radii . 30
Table A.1 - Railway applications – Cables for railway rolling stock , for 90 °C
maximum conductor temperature, Current ratings. 32
Table A.2 - Derating factors for other ambient temperatures . 33
Table A.3 - Correction factors for other maximum conductor temperatures. 33
Table B.1 - Recommended short-circuit current ratings for rolling stock cables of 90 °C
maximum conductor temperature EN 50264 and EN 50382 . 34
Table B.2 - Value of K . 35
---------------------- Page: 5 ----------------------
SIST EN 50355:2014
EN 50355:2013 (E) - 4 -
Foreword
This document (EN 50355:2013) has been prepared by CLC/TC 20 "Electric cables" by Working
Group 12 “Railway cables” as part of the overall programme of work in the Technical Committee
CENELEC TC 9X “Electrical and electronic applications for railways”.
The following dates are fixed:
• latest date by which this document has to be
(dop) 2014-07-01
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards
(dow) 2016-07-01
conflicting with this document have to
be withdrawn
This document supersedes EN 50355:2003.
EN 50355:2013 includes the following significant technical changes with respect to EN 50355:2003:
- requirements for additional cable type: EN 50264-3-1, EN 50264-3-2 and EN 50382-2;
- modified voltage table.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
---------------------- Page: 6 ----------------------
SIST EN 50355:2014
- 5 - EN 50355:2013 (E)
Introduction
The railway industry is generally concerned with the movement of people as well as goods. It
is therefore essential that safety is achieved, even when failures occur which may involve fire,
however caused, affecting railway rolling stock.
Hence it is necessary to provide cables for use in railway environments which minimise the
hazard to people when a fire may damage the cable, irrespective of whether the fire is caused
by an external source or from within the electrical system.
The aims of this European Standard are to:
– inform railway vehicle manufacturers, installers of cables and railway operators of the
properties and limiting conditions of rolling stock cables in order to safeguard life and
equipment;
– avoid misuse of rolling stock cables.
The information is given as limiting values and illustrated by examples which cannot be
exhaustive but nevertheless indicate ways by which safety (a tolerable level of risk) can be
obtained.
It has been assumed in the preparation of this guidance document that the execution of its
provisions will be entrusted to appropriately qualified and experienced people, for whose use
it has been produced.
This European Standard should be used in conjunction with:
EN 50264 series, Railway applications — Railway rolling stock power and control cables
having special fire performance
EN 50306 series, Railway applications — Railway rolling stock cables having special fire
performance — Thin wall
EN 50382 series, Railway applications — Railway rolling stock high temperature power
cables having special fire performance
EN 50343, Railway applications — Rolling stock — Rules for installation of cabling
---------------------- Page: 7 ----------------------
SIST EN 50355:2014
EN 50355:2013 (E) - 6 -
1 Scope
This European Standard gives guidance on the safe use of rolling stock cables specified in
EN 50264, EN 50306 and EN 50382.These cables will only be used for the wiring of railway
rolling stock and within the limits given in the manner described in this European Standard. All
these cables are for fixed installation where there is no free movement of cable, except for
stresses due to typical service.
This European Standard will be applied in conjunction with the relevant product and
installation standards. Stricter requirements than those given in this standard could be
necessary; see in particular EN 50343.
This European Standard is not applicable to:
– intercarriage jumpers;
– cables subject to continual flexing;
– pantograph cables;
– coaxial, data and fibre optic cables;
– wire wrap;
– cables rated at voltages greater than 3,6/6 kV;
– applications other than the cabling of railway rolling stock;
– cables requiring circuit integrity.
Legal or statutory requirements do take precedence over the guidance given in this document.
In cases where no guidance exists or where it cannot be derived from general information, it
is recommended that advice be sought from the cable manufacturer.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 50121-1 Railway applications — Electromagnetic compatibility — Part 1: General
EN 50125-1 Railway applications – Environmental conditions for equipment — Part 1:
Equipment on board rolling stock
EN 50163 Railway Applications — Supply voltages of traction systems
EN 50200 Method of test for resistance to fire of unprotected small cables for use in
emergency circuits
EN 50264-2-1 Railway applications — Railway rolling stock power and control cables
having special fire performance — Part 2-1: Cables with crosslinked
elastomeric insulation — Single core cables
EN 50264-2-2 Railway applications — Railway rolling stock power and control cables
having special fire performance — Standard wall — Part 2-2:Cables with
crosslinked elastomeric insulation — Multicore cables
---------------------- Page: 8 ----------------------
SIST EN 50355:2014
- 7 - EN 50355:2013 (E)
EN 50264-3-1 Railway applications — Railway rolling stock power and control cables
having special fire performance — Part 3-1: Cables with crosslinked
elastomeric insulation with reduced dimensions — Single core cables
EN 50264-3-2 Railway applications — Railway rolling stock power and control cables
having special fire performance — Part 3-2: Cables with crosslinked
elastomeric insulation with reduced dimensions — Multicore cables
EN 50306-2 Railway applications — Railway rolling stock cables having special fire
performance — Thin wall — Part 2: Single core cables
EN 50306-3 Railway applications — Railway rolling stock cables having special fire
performance — Thin wall — Part 3: Single core and multicore cables (pairs,
triples and quads) screened and thin wall sheathed
EN 50306-4 Railway applications — Railway rolling stock cables having special fire
performance — Thin wall — Part 4: Multicore and multipair cables standard
wall sheathed
EN 50343 Railway applications — Rolling stock — Rules for installation of cabling
EN 50362 Method of test for resistance to fire of larger unprotected power and control
cables for use in emergency circuits
EN 50382-2 Railway applications — Railway rolling stock high temperature power cables
having special fire performance — Part 2: Single core silicone rubber
insulated cables for 120 °C or 150 °C
EN 60216-1 Electrical Insulating Materials — Thermal endurance properties — Part 1:
Ageing procedures and evaluation of test results.
3 Terms, definitions
For the purposes of this document the definitions given in EN 50264, EN 50306 and EN 50382
apply.
4 Requirements for safety
4.1 Fundamental requirements
4.1.1 Railway rolling stock cables are intended for the transmission and distribution of
electricity in monitoring, control and power circuits. In the case of normal use, they are to be
regarded as safe. Safety of a cable means that the product does not present an unacceptable
risk of danger to life or property whilst being used in its intended manner.
4.1.2 Unless otherwise stated in the appropriate part of EN 50264, EN 50306 or EN 50382,
cables shall not be used for any other purpose than the transmission and distribution of
electricity in control, monitoring and power circuits.
4.1.3 The test parameters and requirements described in EN 50264, EN 50306 and
EN 50382, and the test methods in EN 50305, are only for the purposes of checking with
respect to safety and quality assurance. They shall not be regarded as providing guidance
that the cables are suitable for service under conditions equivalent to the test conditions.
---------------------- Page: 9 ----------------------
SIST EN 50355:2014
EN 50355:2013 (E) - 8 -
4.2 General requirements
4.2.1 All cables shall be selected so as to be suitable for the voltages and currents likely to
occur under all conditions which are or shall have been anticipated in the equipment or rolling
stock or that part thereof in which they are used.
Care shall be taken when selecting cables that will be subject to traction line voltages due to
transient voltages that may occur (see EN 50163).
4.2.2 Cables shall be constructed, installed, protected, used and maintained so to prevent
danger so far as it is reasonably practical.
4.2.3 All cables shall be selected so as to be suitable for both standard or special ambient
conditions encountered in rolling stock (see EN 50125-1).
The limiting conditions under which the cables can be reasonably expected to operate under
normal circumstances are given in Tables 4 to 14.
These conditions are those considered capable of ensuring an expected period of use which
has been accepted as reasonable by experience of the particular type of cable and in
particular conditions of use. The duration of acceptable performance of a particular type of
cable depends upon the type of use, installation or electrical apparatus and on the particular
combination of influences relating thereto. For example, the acceptable period of use
considered as reasonable for a cable used in a fixed installation, for the distribution of
electricity in rolling stock, is more than that for a cable subject to continual flexing.
For further information on operational life of cables see 6.4 e).
EN 50264, EN 50306 and EN 50382 contain cables with different properties with respect to
temperature, mineral oil and fuel resistance.
---------------------- Page: 10 ----------------------
SIST EN 50355:2014
- 9 - EN 50355:2013 (E)
Table 1 — Properties Available
a b
Low temperature Fuel resistance Code
Normal Normal C
Extra Normal F
c
Normal Extra J
c
Extra Extra M
a
Normal low temperature cables are subject to test at –25 °C, extra low temperature cables at
-40 °C.
b
Normal fuel resistance cables are tested in the test fluid (IRM902). Extra fuel resistance cables
are tested in two test fluids (IRM902 & IRM903) for longer periods of time, at increased temperature.
c
This test is not applicable for EN 50382 cables.
Although the sheaths of cables may be considered resistant to certain fluids, the insulation
used may not be, and this shall be taken into account where cables will be subject to
prolonged exposure to fluids. Care shall also be exercised where fluid can gain access to the
cores at the termination. These cables are not suitable for continuous immersion in fluids; for
this application the advice of the manufacturer shall be sought.
4.2.4 Cables shall be selected so that they are suitable for the operating conditions.
Examples of operating conditions are:
– voltage,
– current,
– protective measures,
– grouping of cables,
– method of installation,
– accessibility.
4.2.5 Cables shall be selected so that they are suitable for any external influences which may
exist. Examples of external influences are:
– ambient temperature,
– presence of rain, steam or accumulation of water,
– presence of corrosive, chemical or polluting substances,
– mechanical stresses (such as through holes or sharp edges in metal work),
– radiation (such as sunlight or luminaires or any sources of ultra violet emission).
In respect to solar radiation, it shall be noted that colour is important, black giving a higher
degree of protection against degradation but higher heat absorption.
It shall be noted that:
– Sheathed cables of EN 50264 and EN 50382, as well as textile braided cables of
EN 50382 and cables of EN 50306-4 class E, are intended for use where the cable is
installed such that it may be subject to mechanical stress and appropriate protection, in
general, is not provided.
– Unsheathed cables of EN 50264, EN 50382, EN 50306-2 and sheathed cables of
EN 50306-3 and EN 50306-4 class P are intended for use in locations where once
installed the cable will be protected so that mechanical stress is unlikely to occur.
---------------------- Page: 11 ----------------------
SIST EN 50355:2014
EN 50355:2013 (E) - 10 -
4.2.6 Consideration shall be given to protection against aggressive agents other than those
for which the cables are designed.
4.2.7 Green-and-yellow coloured cores shall be used for protective earthing purposes only.
4.3 Requirements for installation of cables
4.3.1 Cables shall not be installed in contact with or close to hot surfaces unless the cables
are intended for such conditions.
4.3.2 Cables shall be adequately supported. Recommended maximum spacing of supports is
given in EN 50343.
In deciding the actual spacing, the weight of the cable between the supports shall be taken
into account so that the limiting value of mechanical tension is not exceeded.
The cable shall not be damaged by any mechanical restraint used for its support
4.3.3 Cables which have been in use for long periods may be damaged if they are disturbed.
This can arise from the effect of natural ageing on the materials used for cable insulation and
sheathing, which ultimately results in deterioration of the physical properties of these
materials.
4.3.4 Cables shall not be subject to excessive abrasion, crushing, kinking, and tensile load
(see 6.4) particularly at the point of connection to the fixed equipment. Any strain relief or
clamping device shall not damage the cable.
4.3.5 An earthing core in multicore cables, if present, shall be of such a length that in case of
cable breakage due to tension applied to the cable this core breaks after all other cores.
4.3.6 It should be noted that the use of a class 5 conductor in cables to EN 50264, EN 50306
and EN 50382 does not indicate that the cable is suitable for repeated flexing.
4.4 Electromagnetic compatibility (EMC)
If essential circuits are liable to be subject to electromagnetic interference, screens or
shielding shall be provided and connected using an appropriate method. (See also
EN 50121-1 and EN 50343).
5 Fire
5.1 General
Attention shall be given to the application for which the rolling stock will be used when
assessing requirements of testing for fire.
Rolling stock cables for power, control and associated circuits will, in the event of fire, limit
the risk to people and improve the safety on railways in general. These cables are designed
with halogen free materials. In the event of a fire, they will have limited flame spread and
limited emission of toxic gases. In addition, these cables when burnt produce limited amounts
of smoke. This last characteristic will minimise loss of visibility in the event of a fire and will
aid reduced evacuation times.
5.2 Resistance to fire
Where in the event of a fire, the integrity of a circuit is essential for personnel and equipment
safety, fire resisting (limited circuit integrity) cable shall be used.
---------------------- Page: 12 ----------------------
SIST EN 50355:2014
- 11 - EN 50355:2013 (E)
Cables to EN 50264, EN 50306 and EN 50382 are not specifically designed for this purpose.
Therefore, cables requiring circuit integrity are to be installed according to the instructions of
the cable manufacturer.
It is recommended that such cables shall, in addition to the requirements of EN 50264,
EN 50306 and EN 50382, meet the requirements of EN 50200 or EN 50362.
The voltages to be used for testing should reflect those used in the specific application.
Specific testing methods for cable to EN 50264, EN 50306 and EN 50382 are being developed
for incorporation in EN 50305.
5.3 Reaction to fire
The insulating and sheathing materials referred to in EN 50264, EN 50306 and EN 50382 are
specifically selected to limit the spread of flame, emission of smoke and toxicity consistent
with the required performance of the cable.
6 Limiting conditions
6.1 General
The influence of all factors as outlined in this section shall be considered in combination, not
separately.
6.2 Voltage
The rated voltage of a cable is the reference voltage for which the cable is designed and
which serves to define the electrical tests (see Table 2).
Table 2 — Voltages
Maximum permissible operating voltage
Rated Voltage
AC DC
[U /U]
o
Conductor to Conductor to Conductor to Conductor to
earth conductor earth conductor
[U ] [V ]
m o
a
320 V 320 V 410 V 410 V
300/300 V
b
320 V 550 V 410 V 820 V
300/500 V
0,6/1 kV 0,7 kV 1,2 kV 0,9 kV 1,8 kV
1,8/3 kV 2,1 kV 3,6 kV 2,7 kV 5,4 kV
3,6/6 kV 4,2 kV 7,2 kV 5,4 kV 10,8 kV
NOTE For specific railway rolling stock applications, cables manufactured to EN 50264 and EN 50382, rated at
1,8/3 kV can be used on 3 kV DC systems V with the agreement of the customer.
o
a
Only for EN 50306-2.
b
Multicore cables only.
The rated voltage is expressed by the combination of the following values:
U is the rms. value between any insulated conductor and ‘earth’, i.e. metal covering of
o
the cable or the surrounding medium, e.g. U =600 V;
o
U is the rms. value between any two phase conductors of a multicore cable or of a
system of single core cables, e.g. U= 1 000 V;
---------------------- Page: 13 ----------------------
SIST EN 50355:2014
EN 50355:2013 (E) - 12 -
U is the maximum rms. value of the ‘highest system voltage’ for which the equipment
m
may be used e.g. U =1 200 V.
m
In an alternating current system, the rated voltage of a cable shall be at least equal to the
nominal voltage of the system for which it is intended.
In a direct current system, the cables shall have a maximum voltage to earth (V ) not
o
exceeding 1,5 times the ac rated voltage(U ) of the cable’ where:
o
V is the dc value between any insulated conductor and earth, i.e. metal covering of the
o
cable or the surrounding medium, e.g. V = 900 V.
o
The rated voltage is given in Table 2.
NOTE In the railway industry it is common practice to identify cables and systems by the value of U , not the more
o
usual practice of U.
6.3 Current carrying capacity
6.3.1 The cross sectional area of every conductor size shall be such that its current carrying
capacity is not less than the maximum sustained current which will normally flow through it.
For the purpose of this European Standard, the operating temperature to which the current
carrying capacity is related shall not exceed that appropriate to the type of cable insulation or
sheath concerned.
6.3.2 The recommended basis for continuous current carrying capacities for railway rolling
stock wiring is given in Annex A. Those tabulated in Table A.1 for cables of 90 °C maximum
conductor temperature are derived from IEC 60287. These ratings are based on an ambient
temperature of 45 °C. Table A.2 contains derating factors for other ambient temperatures.
Table A.3 contains correction factors for the other maximum conductor temperatures covered
by this guide to use.
Use of the tabulated values of current rating given will cause a rise in conductor temperature
from that of the ambient air temperature to that of the stated operating temperature. Care
shall be taken to ensure the heat generated can be dissipated and does not cause an
unacceptable rise in the ambient air temperature.
6.3.3 Recommended short circuit current ratings for railway rolling stock wiring are given in
Annex B. For cables of 90 °C maximum conductor temperature these are given in Table B.1.
Table B.2 gives correction factors for the other conductor temperatures covered by this guide
to use. The insulation on these cables is thermally capable of withstanding a short circuit
current condition of 200 °C for 5 s.
Consideration shall be given to the mechanical forces that can be generated in a cable during
a short circuit.
6.3.4 The use of soft soldered joints or terminations is not recommended, and in some
countries not allowed, because the limiting temperature for the conductor under short circuit
conditions is reduced to 160 °C.
6.3.5 Account shall be taken of the installation and operating conditions in determining the
current carrying capacity of a cable (see EN 50343).
Correction factors to be applied to the recommended current carrying capacities may be
available for particular conditions such as:
– type of overcurrent protection;
---------------------- Page: 14 ----------------------
SIST EN 50355:2014
- 13 - EN 50355:2013 (E)
– presence of thermal insulation;
– frequency of supply (if different from 50 Hz etc.);
– effect of harmonics.
These correction factors shall be obtained directly from the manufacturer of the particular
cable.
6.3.6 If cables are operated for any prolonged periods at temperatures above those given in
Annex A then they may be seriously damaged, leading to premature failure, or their properties
significantly reduced.
In special cases, where agreed between a manufacturer and purchaser, cables may be rated
at higher temperatures for a reduced expected lifetime; however, it cannot be assumed that
all cables can be treated in this manner
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.