EN 50343:2003

SLOVENSKI STANDARD
01-december-2003
Železniške naprave – Vozna sredstva – Pravila za inštaliranje kablov
Railway applications - Rolling stock - Rules for installation of cabling
Bahnanwendungen - Fahrzeuge - Regeln für die Installation von elektrischen Leitungen
Applications ferroviaires - Matériel roulant - Règles d'installation du câblage
Ta slovenski standard je istoveten z: EN 50343:2003
ICS:
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50343
NORME EUROPÉENNE
EUROPÄISCHE NORM May 2003
ICS 45.060.01
English version
Railway applications -
Rolling stock -
Rules for installation of cabling

Applications ferroviaires -  Bahnanwendungen -
Matériel roulant - Fahrzeuge -
Règles d'installation du câblage Regeln für die Installation von
elektrischen Leitungen
This European Standard was approved by CENELEC on 2002-12-03. 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, 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 50343:2003 E
Foreword
This European Standard has been prepared by the Working Group B8 of SC 9XB "Electromechanical material
on board of rolling stock" of the Technical Committee CENELEC TC 9X, Electrical and electronic applications for
railways. As the subjects „Cabling“ and „Cables“ have much in common, a close co-operation between the
above Working Group and Working Group 12 „Railway cables“ of CENELEC TC 20 „Electric cables“ has
been maintained during preparation.

The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50343 on
2002-12-03.
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) 2003-12-01

- latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2005-12-01

Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, Annexes A, C, D, E, H and J are normative and Annexes B, F, G, and I are informative.

- 3 - EN 50343:2003
Contents
1 Scope.5
2 Normative references.5
3 Definitions .7
4 Abbreviations .8
5 Technical requirements .9
5.1 General requirements.9
5.2 Selection of type and size of cables .9
5.3 Bundling of cables .15
5.4 Flexibility of cables .15
5.5 Minimum cross-sectional area of conductors .15
5.6 Use of green and yellow colour .16
5.7 Bending radii and other mechanical requirements .16
5.8 Re-termination.16
5.9 Busbars.16
5.10 Connections to busbars .16
5.11 Separation of cables with different voltage ratings or power levels for safety reasons .16
5.12 Provisions for refurbishment and maintenance, including inspection and repair.18
5.13 Fire prevention, cable laying and cabling behaviour in case of fire .18
5.14 Provision of spares for control cabling.19
5.15 Requirements for fixing .19
5.16 Clearances and creepage distances.20
5.17 Requirements for terminating conductors .20
5.18 Use of heat-shrinkable sleeves .22
5.19 Connections for return current.23
6 EMC requirements.23
6.1 General.23
6.2 Cable categories.23
6.3 Separation of cables .23
6.4 Return conductor.24
6.5 Use of conductive structure.24
6.6 Shielding and earthing .24
6.7 Supply connection from battery .25
6.8 Databus lines.25
7 Marking.25
7.1 General.25
7.2 Marking of cables.25
7.3 Marking of terminal blocks, individual terminals, plugs and sockets, busbars .26
7.4 Marking of insulators.26
7.5 Marking for warning against electrical shock .26
7.6 Marking using heat-shrinkable sleeves.26
8 Testing.26
8.1 General concerning testing .26
8.2 Electrical insulation tests .26
Annex A (normative) Cable sizing - Calculation of load current under short time load conditions .30
Annex B (informative) Cable sizing - Examples of current ratings.31
Annex C (normative) Cable sizing - Calculating current ratings for temperature classes other t
han 90 °C .32
Annex D (normative) Cable sizing - Correction factor k for expected ambient temperature .33
Annex E (normative) Cable sizing - Prediction of cable lifetime .34
Annex F (informative) Cable sizing - Calculation examples .35
Annex G (informative) Termination methods.37
Annex H (normative) Tests on marking when using heat-shrinkable sleeves .39
Annex I (informative) Effects of the number of earth connections to a cable screen .40

Annex J (normative) Items to be agreed between manufacturer and purchaser .41
Bibliography.42

Figures
Figure 1 - Example of short circuit condition where cable size will have influence on
protection device behaviour .10
Figure 2 - Cable grouping and installation conditions .14
Figure 3 - Locations in rolling stock, concerning use of minimum cross-sectional areas for conductors .15
Figure 4 - Separation of cables by required distance: D > 2 d and D > 0,1 m.17
Figure 5 - Examples of separation of cables by barriers or by insulation .18
Figure 6 - Dimensions for calculating the effective area of a contact .22
Figure 7 - Examples of cable or plug constructions where identification is done by configuration .25
Tables
Table 1 - Modification factor k for installation type (grouping and installation conditions) .13
Table 2 - Selection of cable conductor size on the basis of rating of protection device .14
Table 3 - Example of division of cables into three categories for safety reasons .17
Table 4 - Examples for allowed and forbidden numbers of contact interfaces.21
Table 5 - Cable categories with respect to EMC.23
Table 6 - Minimum distances between cables of different EMC categories .24
Table 7 - Test voltages according to on-board voltages.28
Table 8 - Test voltages according to supply line voltages.28
Table A.1 - Modification factor k .30
Table B.1 - Examples of current ratings for standard wall cables, with 90 °C maximum
conductor operating temperature .31
*
Table C.1 - Factor k , used when comparing current ratings for 90 °C maximum conductor
operating temperature with other temperature classes .32
Table D.1 - Modification factor k .33
Table E.1 - Examples of values of correction factor k to allow for decrease in
predicted cable lifetime .34
Table G.1 - Methods of terminating cables, conductor side .37
Table G.2 - Methods of terminating cables, terminal side .38
Table H.1 - Preparation of heat-shrinkable sleeve for test of marking quality.39
Table I.1 - Effects of shielding .40

- 5 - EN 50343:2003
1 Scope
This European Standard specifies requirements for the installation of cabling on railway vehicles and within
electrical enclosures on railway vehicles, including magnetic levitation trains and trolley buses.
NOTE With respect to trolley buses, this standard applies to the whole electric traction system, including current collecting circuits,
power converters and the respective control circuits. The installation of other circuits is covered by street vehicle standards for example
those for combustion driven buses.
This standard covers cabling for making electrical connections between items of electrical equipment,
including cables, busbars, terminals and plug/socket devices. It does not cover special effect conductors like
fibre optic cables or hollow conductors (waveguides).
The material selection criteria given here are applicable to cables with a copper conductor.
This standard is not applicable to the following:
- special purpose vehicles, such as track-laying machines, ballast cleaners and personnel carriers;
- vehicles used for entertainment on fairgrounds;
- vehicles used in mining;
- electric cars;
- funicular railways.
As the field of cabling in rolling stock is also dealt with in the cable makers’ standard, references are made to
EN 50264, EN 50306 and EN 50355.
This European Standard applies in conjunction with the relevant product and installation standards. Stricter
requirements than those given in this standard may be necessary.
2 Normative references
This European Standard incorporates by dated or undated references, provisions from other publications.
These normative references are cited at the appropriate place 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.
1)
EN 45545-1 Railway applications - Fire protection on railway vehicles - Part 1: General
1)
EN 45545-5 Railway applications - Fire protection on railway vehicles - Part 5: Fire safety
requirements for electrical equipment including that of trolley buses, track guided
buses and magnetic levitation vehicles
EN 50121-3-1 Railway applications - Electromagnetic compatibility - Part 3-1: Rolling stock - Train
and complete vehicle
EN 50121-3-2 Railway applications - Electromagnetic compatibility - Part 3-2: Rolling stock -
Apparatus
EN 50124-1 Railway applications - Insulation coordination - Part 1: Basic requirements -
Clearances and creepage distances for all electrical and electronic equipment
EN 50125-1 Railway applications - Environmental conditions for equipment - Part 1: Equipment on
board rolling stock
EN 50153 Railway applications - Rolling stock - Protective provisions relating to electrical hazards
EN 50200 Method of test for resistance to fire of unprotected small cables for use in emergency
circuits
1)
At draft stage.
EN 50215 Railway applications - Testing of rolling stock after completion of construction and
before entry into service
EN 50264-1 Railway applications - Railway rolling stock cables having special fire performance -
Standard wall - Part 1: General requirements
EN 50264-2 Railway applications - Railway rolling stock cables having special fire performance -
Standard wall - Part 2: Single core cables
EN 50264-3 Railway applications - Railway rolling stock cables having special fire performance -
Standard wall - Part 3: Multicore cables
EN 50306-1 Railway applications - Railway rolling stock cables having special fire performance -
Thin wall - Part 1: General requirements
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
1)
EN 50355 Railway applications - Railway rolling stock cables having special fire performance -
Thin wall and Standard Wall - Guide to use
EN 60352-1 Solderless connections - Part 1: Wrapped connections - General requirements, test
methods and practical guidance (IEC 60352-1)
EN 60352-7 Solderless connections - Part 7: Spring-clamp connections - General requirements,
test methods and practical guidance (IEC 60352-7)
EN 60684-3-212 Flexible insulating sleeving - Part 3: Specifications for individual types of sleeving -
Sheet 212: Heat-shrinkable polyolefin sleeving, flame retarded, shrink ratio 2:1
(IEC 60684-3-212)
1)
EN 60684-3-216 Flexible insulating sleeving - Part 3: Specifications for individual types of sleeving -
Sheet 216: Heat-shrinkable, flame retarded, limited fire-hazard sleeving
(IEC 60684-3-216)
EN 60684-3-217 Flexible insulating sleeving. Part 3: Specifications for individual types of sleeving -
Sheet 217: Heat-shrinkable polyolefin sleeving, flame retarded shrink ratio 3:1
(IEC 60684-3-217)
EN 60684-3-271 Flexible insulating sleeving - Part 3: Specifications for individual types of sleeving -
Sheet 271: Heat-shrinkable elastomer sleeving, flame retarded, fluid resistant, shrink
ratio 2:1 (IEC 60684-3-271)
EN 60947-7-1 Low-voltage switchgear and controlgear - Part 7-1: Ancillary equipment - Terminal
blocks for copper conductors (IEC 60947-7-1)
EN 60947-7-2 Low-voltage switchgear and controlgear - Part 7-2: Ancillary equipment - Protective
conductor terminal blocks for copper conductor (IEC 60947-7-2)
EN 60998-2-2 Connecting devices for low-voltage circuits for household and similar purposes -
Part 2-2: Particular requirements for connecting devices as separate entities with
screwless-type clamping units (IEC 60998-2-2)
1)
EN 60999-2 Connecting devices - Electrical copper conductors - Safety requirements for screw-
type and screwless-type clamping units - Part 2: Particular requirements for clamping
units for conductors above 35 mm² up to 300 mm² (included) (IEC 60999-2)
EN 61210 Connecting devices - Flat quick-connect terminations for electrical copper conductors -
Safety requirements (IEC 61210, modified)
EN 61310-1 Safety of machinery - Indication, marking and actuation - Part 1: Requirements for
visual, auditory and tactile signals (IEC 61310-1)
HD 383 S2 Conductors of insulated cables – First supplement: Guide to the dimensional limits of
circular conductors (IEC 60228:1978 + IEC 60228A:1982, modified)

- 7 - EN 50343:2003
HD 384.4.43 S2 Electrical installations of buildings -- Part 4: Protection for safety -- Chapter 43:
Protection against overcurrent (IEC 60364-6-43:1977 + A1:1997, modified)
HD 384.5.54 S1 Electrical installations of buildings - Part 5: Selection and erection of electrical
equipment - Chapter 54: Earthing arrangements and protective conductors
(IEC 60364-5-54:1980, modified)
HD 588.1 S1 High-voltage test techniques - Part 1: General definitions and test requirements
(IEC 60060-1:1989 + corrigendum March 1990)
IEC 60050-461 International Electrotechnical Vocabulary - Chapter 461: Electric cables
ISO 1302 Geometrical Product Specifications (GPS) – Indication of surface texture in technical
product documentation
3 Definitions
For the purposes of this standard, the following definitions apply. Reference is made to IEC 60050-461.
3.1
cable
assembly consisting of
- one or more cores (screened or unscreened),
- their individual covering(s) (if any),
- assembly protection (if any),
- screen(s) (if any),
- sheath (if any)
[461-06-01, mod.]
3.2
conductor (of a cable)
part of a cable which has the specific function of carrying current
[461-01-01]
3.3
core
assembly comprising a conductor with its own insulation (and screens if any)
[461-04-04]
3.4
solid conductor
conductor consisting of a single wire
[461-01-06, mod.]
3.5
stranded conductor
conductor consisting of a number of individual wires or strands all or some of which generally have a helical
form
[461-01-07, mod.]
3.6
busbar
conductor consisting of a rigid metal profile

3.7
screen (of a cable)
conducting layer(s) having the function of control of the electro magnetic field within the cable and/or to
protect the cable from external electro magnetic influences
[461-03-01, mod.]
3.8
bundle
group of cables tied together
3.9
bolted connection
connection in which the pressure to the conductor is applied by bolting
[461-19-05]
3.10
crimp
cable termination in which a permanent connection is made by applying pressure, inducing the deformation
or reshaping of a barrel part of the termination around the conductor
[461-19-01, mod.]
3.11
spring-clamp connection
terminal connection in which the pressure between the conductor and terminal is applied by a spring
3.12
penetration (connection)
terminal connection in which the contact with the conductor is achieved by jaws which penetrate the insulation
3.13
plug
connector intended to be coupled at the free end of an insulated conductor or cable, to be inserted into a
matching socket, or readily removed when required
3.14
socket
connector intended to be mounted on a rigid surface and to hold a matching plug, such that the conductors
contained within the socket make electrical contact individually with those in the plug
3.15
heat-shrinkable sleeve
plastic tube that on exposure to heat during installation, will at a critical temperature, permanently reduce in
diameter, while increasing in wall thickness
3.16
manufacturer
organisation that has the responsibility for the supply of vehicle(s), equipment or groups of equipment to the
purchaser
3.17
purchaser
organisation that orders the vehicle or equipment or groups of equipment and has the responsibility for direct
negotiations with the manufacturer
4 Abbreviations
EMC Electromagnetic compatibility

- 9 - EN 50343:2003
5 Technical requirements
5.1 General requirements
Cables and installation materials shall be type tested, selected for size and installed so as to be suitable for
their function under their operating conditions. Size and installation of cables (or busbars) shall take into
account the particular stresses to be expected in rolling stock. The materials used and methods of cabling
shall be such as to prevent strain or chafing and excessive lengths of unsupported cable shall be avoided.
Cables on rolling stock shall not be used for any purpose other than for transmission, distribution and
collection of electrical energy, electrical controls or monitoring systems. All components of cabling shall be
selected, installed, protected, used and maintained so as to prevent danger (e.g. electrical or fire hazard,
EMC problems).
The electrical connections shall be made in such a way that they can not be unintentionally disconnected or
interrupted during service by thermal effects, dynamic loads as shock, vibration, car body motions, etc. that
are to be expected.
Where ambient conditions are considered, EN 50125-1 shall apply.
For protection against electrical hazard, the cabling installed shall be in accordance with EN 50153.
5.2 Selection of type and size of cables
5.2.1 General
When selecting cables or busbars the expected operating conditions should be taken into account. These
should include but are not limited to the following parameters:
- voltage;
- current;
- overload current;
- voltage drop;
- short circuit current;
- shape and frequency of current;
- fusing characteristic of the protection device;
- grouping of cables;
- ambient temperature and temperature due to load current;
- methods of installation;
- predicted cable lifetime;
- presence of rain or steam or snow or accumulation of condensing water;
- presence of corrosive, polluting or damaging substances;
- mechanical stresses;
- radiation such as sunlight.
Consideration should be given to the expected lifetime of the cabling compared with the expected lifetime of
the vehicle.
The cable type (i.e. cable family) shall be selected in accordance with EN 50264 or EN 50306 etc, as
applicable.
Once the cable type has been selected, the selection of conductor size when the cable is intended for power
distribution shall be based on either load current and current carrying capacity calculated in accordance with
5.2.3, or based on protection device size in accordance with 5.2.4.

Short circuit conditions should additionally be checked according to HD 384.4.43 S2. Recommended short
circuit ratings for rolling stock cables are given in EN 50355. Short circuit conditions and overload conditions
should be checked with respect to the fusing characteristic of the protection device and the resistance of the
chosen cable. See example in Figure 1.

NOTE 1 This short circuit or overload case should be checked according to
Normal load < nominal switching level of protection device < current carrying capacity of the cable (I , see definition in 5.2.3 b) ).
corr
+
Power supply
Protection device
Short circuit Impedance of complete current path
Load
0V
Figure 1 – Example of short circuit condition where cable size will have influence on protection
device behaviour
The cross-sectional area of any conductor shall be not less than the value specified in 5.5.

Only cabling which conforms to the fire safety requirements specified in Clause 6 of EN 45545-1 and
EN 45545-5 shall be used.
NOTE 2 The number of different types of cables installed on any one type of vehicle should be minimized for practical reasons.

5.2.2 Selection of cable size for control cables
Control cables, which are intended to carry control signals only, shall have a minimum conductor cross-
sectional area as specified in 5.5. This is also valid if the load current would make a smaller cross-sectional
area possible.
NOTE It is not necessary for the conductor size of these cables to be selected according to 5.2.3.
5.2.3 Selection of cable size for cables for power distribution, on the basis of load current
This subclause specifies a method for calculation of continuous maximum load current of different cable
sizes dependent on their method of installation and ambient temperature, to enable cables to be selected so
as to ensure that the predicted lifetime is achieved.

The continuous maximum conductor temperature for the cable types defined in the various parts of
EN 50264 and EN 50306 is either 90 °C or 105 °C. This is based either on proven experience and reliability
over many years or in the case of newer, less well defined, insulations upon an acceptance test, using long-
term thermal endurance ageing to demonstrate a lifetime of at least 20 000 h at 110 °C and 125 °C
respectively (i.e. 20 °C above the continuous rating). Data from this thermal testing can, with care, be
extrapolated to the conductor temperature to provide a predicted lifetime of the cable when continuously
loaded. This predicted lifetime may be used in conjunction with the known duty cycle of the vehicle, and its
predicted time out of service, to estimate the ability of the cable to function reliably for the predicted lifetime of
the whole vehicle.
NOTE 1 Because the cable standards allow a variety of solutions for insulation type, it is important to confirm lifetime extrapolations
with the cable manufacturer.
NOTE 2 A predicted lifetime of cable of 100 000 h may be used as a theoretical basis value.

NOTE 3 This subclause only deals with thermal degradation of insulation material and it should be noted that mechanical stresses
(wear, etc.) and other environmental factors (such as presence of fluids such as cleaning detergents, aggressive atmosphere) may be
the limiting factor determining predicted cable lifetime.

For cables intended for power distribution, the cable size shall be selected on the basis of the load current
and the current carrying capacity in accordance with the following procedure (i.e. the three steps a), b)
and c)).
- 11 - EN 50343:2003
a) The load current
The load current I , in amperes (A) which a cable has to carry for sustained periods during normal service
load
shall be a basic value for cable sizing.

When the circuit(s) being supplied by the cable is in continuous or sustained cyclic operation, I shall be
load
calculated according to the following equation:

I = i dt
load
∫
t
where
t is the duration of a typical duty cycle during service, in minutes (min)
i is the instantaneous current – including overload, if any - in amperes (A).

NOTE 4 For continuous direct current operation, the above equation has the simple form I = i .
load
When operation is not continuous or sustained cyclic, I shall be calculated according to Annex A.
load
b) The current carrying capacity

The permissible continuous current carrying capacity I in amperes (A) of a single-core cable being
cable
operated in free air shall be another basic value for cable sizing. A particular value of I is valid for a
cable
particular reference ambient temperature T and for a particular maximum conductor temperature in
ref
service, T .
c(max)
The values I , T and T to be used, shall be those provided by the cable manufacturer, however,
cable ref c(max)
some examples are presented in Annex B.

I for maximum conductor temperatures other than T = 90 °C, shall be calculated according to
cable c(max)
Annex C.
The current carrying capacity of the cable in service, I , in amperes (A) shall be calculated from I using
corr cable
correction factors to take into account the expected ambient temperature, the installation type, etc., in
accordance with the following equation.

I = I × k × k × k × k
corr cable 1 2 3 4
where
k is a correction factor for the expected ambient temperature. It shall be calculated according to the following
formula:
T -T
c(max)
k =
T -T
c(max) ref
where
T is the maximum conductor temperature, in degrees Celsius (°C), in service, which will allow the
c(max)
predicted lifetime of the cable to be achieved.

T is the estimated value of the actual ambient temperature, in degrees Celsius (°C) during operation, on the
outside of the bundle or of the tube - if any. T is an average value.

T is the reference ambient temperature, in degrees Celsius (°C), for which the I value is valid.
ref cable
Examples of k values are given in Annex D, Table D.1.
k is a correction factor for installation type (grouping and installation conditions).
Values for k given in Table 1 shall be used. Interpolation between the different numbers of cables in
Table 1 is allowed.
k is a correction factor to allow for a decrease in predicted cable lifetime, calculated according to the
formula in Annex E. In all cases where the standard predicted cable lifetime shall be used, the value of k
shall be 1,0.
k is a correction factor to take into account short time current when operation is not continuous, calculated
according to the procedure in Annex A. When operation is continuous, the value of k shall be 1,0.
c) Selection of cable size
The cable size shall be selected such that the current carrying capacity of the cable in service, calculated in
accordance with item b) is greater than or equal to the predicted load current, calculated in accordance with
item a) i.e.
I ≤ I
load corr
The minimum cross-sectional area of the conductor shall be as specified in 5.5.

NOTE 5 Combining the formulas and equations from 5.2.3 a) and b) and c), would lead to the following equation:

I
load
I ≥
cable
k × k × k × k
1 2 3 4
This equation will in practice be more easy to use, because in cases with defined cable type and defined load conditions the last term
will be constant and so it is easy to find the right cable size I in the current ratings table (see examples in Annex B, Table B.1).
cable
Some calculation examples are given in Annex F.

- 13 - EN 50343:2003
Table 1 - Modification factor k for installation type (grouping and installation conditions)
Installation type
Number of cables being
Cable in Cables on Cables on Cables in
simultaneously loaded
free air trays, in trays, in closed tube
one layer several layers
Type a) Type b) Type c) Type d)
1 single cable 1,0 1,0 - 0,76
4 cables together - 0,78 0,71 0,56
8 cables together - 0,74 0,52 0,40
12 cables together - 0,73 0,45 0,34
16 cables together - 0,72 0,41 0,31
17 cables and above - 0,71 0,38 0,29
together
NOTE 1 Details of installation types are as follows:

Type a) One single cable in free air with heat dissipation into the surrounding air ensured by all the following
measures:
- distance between the cable and adjacent walls over, under or beside: At least equal to the cable diameter;
- distance between the cable and any other cable lying beside it in any direction: At least equal to the sum of the
adjacent cable diameters;
- cable lying in an open tray or ladder support with perforations, the total area of the perforations being at least 15 %
of the total supporting area in case of metallic tray or support with good thermal contact to carbody (otherwise at
least 30 %), and without any cover.

Type b) Cables lying in one layer, touching each other, on an open tray or ladder support, with perforations as for
type a).
Type c) As for type b) but cables in several layers over each other.

Type d) Cables lying in bundles in closed tubes or boxes without significant air flow.

NOTE 2 Installation types a), b), c) and d) are illustrated in Figure 2.

a)
b)
min.D min.(D+d)
D
d
minimum value
minimum value
see NOTE 1 in Table 1
c)
d)
minimum
value
Figure 2 - Cable grouping and installation conditions

5.2.4 Cables intended for power distribution – Selection on the basis of rating of protection
device
In cases where the load current I is not exactly defined, the rating of the protection device may be chosen
load
according to the maximum load current that can be expected. The conductor size shall then be selected
according to the rating of protection device in accordance with Table 2. This applies to all cable types with
T of at least 90 °C, at an ambient temperature of maximum 45 °C.
c(max)
NOTE This method is simple but has disadvantages (weight, required space and costs of cables may increase).

Table 2 - Selection of cable conductor size on the basis of rating of protection device
Rating of Nominal cross-sectional area of
protection conductor
device
mm²
A
Up to 4-core Up to 4 cables in
cables, or a closed tube
bundles of max. 4
cables, on open
trays or in free air
6 1,0 1,0
10 1,0 1,5
16 1,5 2,5
20 2,5 4,0
25 4,0 6,0
- 15 - EN 50343:2003
5.2.5 Motor cables
Traction motor cables shall be sized according to the procedure specified in 5.2.3. Higher flexibility of cables
should be considered when selecting cable type (i.e. class 6, see 5.4).
5.2.6 Cables for protective bonding
Cables for protective bonding shall be sized and installed according to HD 384.5.54 S1.
NOTE Cables for protective bonding should be marked according to EN 50153.
5.3 Bundling of cables
If several cables are to be laid together as a bundle, the following factors should at least be taken into
consideration:
- thermal requirements (see 5.2.3);
- EMC requirements (see 6.2);
- insulation levels (see 5.11);
- mechanical aspects, such as strength of bundle, weight of bundle and available space.

If cables with different cross-sectional area are to be bundled together, the mechanical stresses should be
considered.
5.4 Flexibility of cables
If high flexibility is required, stranded conductors of class 6 in accordance with HD 383 S2 should be used. In
all other cases, stranded conductors of class 5 in accordance with HD 383 S2 shall be used (see also 5.7).
NOTE 1 Internal connections of, for example, electronic devices, may use single solid conductors of class 1 in accordance with
HD 383 S2 (e.g. for wire wrap connections) if there is no risk of fatigue failure or if precautions have been taken to avoid this risk.
NOTE 2 When higher flexibility of a bundle is required, the nominal cross-sectional area of each individual cable should be selected
with respect to its individual load current. In many cases, the smaller the cross-section of a conductor, the more flexible the cable is.
5.5 Minimum cross-sectional area of conductors
Single-core cables laid separately, or cables laid side by side, connecting electrical components in different
locations inside rolling stock vehicles (e.g. for connections between locations A, B and C as shown in
Figure 3) shall have a nominal conductor cross-sectional area of at least 1,0 mm².
NOTE Higher minimum cross-sections may be necessary due to voltage drop or load current or other effects, or to provide the
necessary mechanical strength.
Smaller cross-sectional areas shall be allowed under the following conditions:
- for internal wiring in racks or assemblies or in electronic equipment or precabled devices, if the circuit is
protected against overload and if the mechanical strength is given (e.g. inside A or B or C as shown in
Figure 3);
- for multi-core cables, bundled cables, databus connections etc., if the mechanical strength is provided and
if the load current in all operational cases allows this;
- for devices specified and tested as a complete unit for use in rolling stock.

Figure 3 - Locations in rolling stock, concerning use of minimum cross-sectional areas
for conductors
5.6 Use of green and yellow colour
When the protective earth conductor in rolling stock is identified by colour, a green/yellow combination shall
be used (general abbreviation GNYE).
The green/yellow core of a multi-core cable - if any - shall not be used for purposes other than earthing or
protective bonding.
NOTE In multi-core cables, individual cores may be either green or yellow.
5.7 Bending radii and other mechanical requirements
Cables shall be installed so that the minimum bending radii for fixed-installation cables and cables which are
flexing during service are not less than those given in the relevant product information or cable standard.
The cable material should be considered carefully with respect to its ability to resist the effects of dynamic
movement. Excessive forces on the installation devices used – e.g. fastening clamps and termination points -
should be avoided as far as possible, for example by using extra fixing means or more flexible cables.
NOTE 1 Mechanical stresses are detailed in EN 50355.
NOTE 2 The bending radius can have influence on the EMC effects of screened cables.
5.8 Re-termination
Single- and multi-core cables with a nominal conductor cross-sectional area of 16 mm² or less installed on
rolling stock should have sufficient spare length at each termination to allow for at least 3 re-terminations.
NOTE When cables are terminated by a plug, it may be impractical to provide any spare length.
5.9 Busbars
Busbars should be made of copper or aluminium. On contact surfaces, precautions shall be taken to prevent
contact resistance values from increasing with time in particular due to corrosion effects or creep.
Busbars shall conform to the relevant international, European or national standard. The selection of the type
and dimensions of busbars shall be at the discretion of the vehicle manufacturer. The sizing procedure shall
include the influence of ambient temperature.
5.10 Connections to busbars
Electrical connections between busbars and equipment or between different bar sections or between different
devices shall be flexible if relative movement can be expected.
Bolted connections shall be used, with suitable locking arrangement, that will retain their mechanical forces
nearly constant over the lifetime of the equipment, including any material creepage.
5.11 Separation of cables with different voltage ratings or power levels for safety reasons
Measures in order to prevent electrical hazards to persons shall be according to EN 50153.
EN 50153 specifies the use of measures like bonding, insulat
...