SIST EN 50305:2020
(Main)Railway applications - Railway rolling stock cables having special fire performance - Test methods
Railway applications - Railway rolling stock cables having special fire performance - Test methods
This document specifies special test methods applicable to cables, and their constituent insulating and sheathing materials, for use in railway rolling stock. Such cables are specified in the various parts of the EN 50264 series, EN 50306 series and EN 50382 series.
Other test methods required for railway rolling stock cables and their insulating and sheathing materials are listed in Annex A.
Bahnanwendungen - Kabel und Leitungen für Schienenfahrzeuge mit verbessertem Verhalten im Brandfall - Prüfverfahren
Applications ferroviaires - Câbles pour matériel roulant ferroviaire ayant des performances particulières de comportement au feu - Méthodes d'essais
Le présent document définit les méthodes d'essais spéciaux relatives aux câbles et à leurs matériels d'isolation et de gainage constitutifs, utilisés dans le matériel roulant ferroviaire. Ces câbles sont spécifiés dans les différentes parties de la série EN 50264, de la série EN 50306 et de la série EN 50382.
D'autres méthodes d’essai exigées pour les câbles de matériel roulant ferroviaire et leurs matériels d'isolation et de gainage correspondants sont indiquées à l’Annexe A.
Železniške naprave - Kabli v železniških vozilih s posebno požarno odpornostjo - Preskusne metode
General Information
Relations
Overview
EN 50305:2020 - Railway applications: Railway rolling stock cables having special fire performance - Test methods - is a CENELEC/CLC standard that defines the specialized test methods used to assess cables and their insulating and sheathing materials for use in railway rolling stock. It updates and supersedes EN 50305:2002 and centralizes test procedures needed for cables covered by the EN 50264, EN 50306 and EN 50382 product series. The standard is focused on ensuring safety in fire scenarios by specifying how to evaluate mechanical, electrical, thermal and fire-related behaviour, including halogen content and toxicity.
Key topics and technical requirements
EN 50305:2020 organizes practical test methods and requirements across the full lifecycle of cable assessment:
- Sampling and test-piece preparation - applicability, classification of tests and pre-conditioning requirements.
- Mechanical tests - impact at low temperature, abrasion resistance, notch propagation, pliability, strippability, adhesion and dynamic cut-through.
- Electrical tests - conductor resistance, voltage tests for completed cables and sheaths, insulation resistance (ambient and elevated), spark testing, surface resistance, DC stability and dielectric strength.
- Ageing and thermal tests - compatibility, long-term ageing (improved and adapted in 2020 revision), ozone resistance, high-temperature pressure tests, shrinkage and stress cracking.
- Fluid resistance - mineral/fuel oil, acid/alkali resistance and sheath water absorption.
- Fire performance - flame propagation tests by cable diameter class, toxicity analysis (qualitative and quantitative), and calculation of toxicity indices.
- Halogen and marking - methods for halogen determination, halogen-free definition (moved into EN 50305 in this edition), durability of marking and blocking of cores.
- Normative and informative annexes - detailed procedures for spark-test efficacy, toxicity analysis, halogen elemental testing, long-term ageing interpretation and a list of other applicable test methods (Annex A).
Practical applications and users
EN 50305:2020 is used by:
- Cable manufacturers for product development, type testing and demonstrating compliance with railway fire-safety requirements.
- Test laboratories implementing standardized mechanical, electrical, thermal and fire tests.
- Rolling-stock OEMs and system integrators specifying cables for new vehicles or refurbishments to meet safety and regulatory expectations.
- Procurement and compliance teams evaluating suppliers and ensuring products meet halogen-free and low-toxicity criteria.
- Regulators and safety engineers assessing fire risk mitigation measures for passenger and freight rolling stock.
Related standards
Key referenced standards and series related to EN 50305:2020:
- EN 50264 series (railway power and control cables)
- EN 50306 series (thin-wall rolling stock cables)
- EN 50382 series (high-temperature rolling stock cables)
- EN 60216, EN 60332-3-25, EN 60754-1/-2, EN 60811, EN 62230
EN 50305:2020 provides the consolidated test-method backbone needed to verify that railway rolling stock cables meet stringent fire performance, ageing and safety expectations.
Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2020
Nadomešča:
SIST EN 50305:2002
Železniške naprave - Kabli v železniških vozilih s posebno požarno odpornostjo -
Preskusne metode
Railway applications - Railway rolling stock cables having special fire performance - Test
methods
Bahnanwendungen - Kabel und Leitungen für Schienenfahrzeuge mit verbessertem
Verhalten im Brandfall - Prüfverfahren
Applications ferroviaires - Câbles pour matériel roulant ferroviaire ayant des
performances particulières de comportement au feu - Méthodes d'essais
Ta slovenski standard je istoveten z: EN 50305:2020
ICS:
13.220.40 Sposobnost vžiga in Ignitability and burning
obnašanje materialov in behaviour of materials and
proizvodov pri gorenju products
29.060.20 Kabli Cables
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 50305
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2020
ICS 29.060.20; 45.060.01 Supersedes EN 50305:2002 and all of its amendments
and corrigenda (if any)
English Version
Railway applications - Railway rolling stock cables having
special fire performance - Test methods
Applications ferroviaires - Câbles pour matériel roulant Bahnanwendungen - Kabel und Leitungen für
ferroviaire ayant des performances particulières de Schienenfahrzeuge mit verbessertem Verhalten im
comportement au feu - Méthodes d'essais Brandfall - Prüfverfahren
This European Standard was approved by CENELEC on 2019-12-30. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50305:2020 E
Contents Page
European foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .7
4 Applicability, sampling, test-piece preparation and test conditions .7
4.1 Applicable tests .7
4.2 Classification of tests .7
4.3 Sampling .7
4.4 Test-piece preparation .7
4.5 Test conditions .7
4.5.1 Ambient temperature .7
4.5.2 Tolerance on temperature values .7
4.5.3 Frequency and waveform of power frequency test voltages .8
4.5.4 Pre-conditioning .8
5 Mechanical tests .8
5.1 Impact test at low temperature .8
5.2 Abrasion resistance .8
5.3 Notch propagation .9
5.4 Pliability (only applicable for cable in according to EN 50306 series) . 10
5.5 Strippability and adhesion of insulation (only applicable for cable in according to
EN 50306 series) . 11
5.5.1 Strippability . 11
5.5.2 Adhesion . 11
5.6 Dynamic cut-through (only applicable for cable in according to EN 50306 series) . 11
6 Electrical tests . 12
6.1 Electrical resistance of conductors . 12
6.2 Voltage test on completed cable . 12
6.2.1 Cable without metallic layer. 12
6.2.2 Cable with one or more metallic layers . 12
6.3 Voltage test on sheath . 12
6.4 Insulation resistance . 13
6.4.1 Test at ambient temperature . 13
6.4.2 Test at elevated temperature . 13
6.5 Spark test. 13
6.5.1 General . 13
6.5.2 Method. 13
6.6 Surface resistance . 13
6.7 DC stability. 14
6.8 Dielectric strength . 15
7 Ageing and thermal tests. 15
7.1 Compatibility . 15
7.2 Long term ageing . 15
7.2.1 General . 15
7.2.2 Summary of test method . 15
7.2.3 Apparatus . 16
7.2.4 Method. 16
7.3 Long term ageing for sheath and insulation where winding test is not possible . 18
7.4 Ozone resistance . 18
7.4.1 Electrical test . 18
7.4.2 Non-electrical test . 18
7.5 Pressure test at high temperature . 20
7.6 Shrinkage test for insulation . 20
7.7 Stress cracking test . 20
7.7.1 General . 20
7.7.2 Preparation of test assemblies . 20
7.7.3 Determination of the 168 h thermal ageing test temperature . 21
7.7.4 Test method . 22
8 Tests in fluids, including water . 22
8.1 Mineral and fuel oil resistance . 22
8.2 Acid and alkali resistance . 22
8.3 Water absorption of sheath . 22
9 Fire performance tests . 23
9.1 Flame propagation . 23
9.1.1 Cables with overall diameter greater than 6 mm and less than 12 mm . 23
9.1.2 Cables with overall diameter not greater than 6 mm . 23
9.2 Toxicity . 23
9.2.1 General . 23
9.2.2 Qualitative analysis for nitrogen and sulfur using molten sodium . 24
9.2.3 Quantitative analysis . 24
9.2.4 Index calculation . 26
10 Miscellaneous tests . 27
10.1 Durability of marking . 27
10.2 Blocking of cores . 27
10.3 Determination of halogen content . 27
Annex A (informative) List of other test methods applicable to rolling stock cables . 28
Annex B (normative) Procedure for checking the efficacy of the method of spark testing (with
reference to 6.5) . 29
Annex C (informative) Long term ageing test – Significance and use . 31
Annex D (informative) Illustration of an Arrhenius plot . 32
Annex E (normative) Analysis methods for toxicity . 33
Annex F (normative) Halogen-Free . 39
Annex G (normative) Determination of halogens – Elemental test . 41
Bibliography . 43
European foreword
This document (EN 50305:2020) has been prepared by CLC/TC 20, “Electric cables”.
The following dates are fixed:
• latest date by which this document has (dop) 2020-12-30
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2022-12-30
standards conflicting with this document
have to be withdrawn
This document supersedes EN 50305:2002 and all of its amendments and corrigenda (if any).
— a new cable standard EN 50382 series has been added to EN 50305;
— the long term ageing test part is improved and adapted to the whole range of products;
— the requirements are now clearly described and give more information for the test laboratories;
— the definition of “halogen free” in Annex F and the determination of halogens element test in
Annex G are moved from the product standard (EN 50306 series) to EN 50305.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Introduction
The railway industry is generally concerned with the movement of people as well as goods. It is
therefore essential that a high level of safety is achieved, even when failures occur which could
involve fire, howsoever caused, affecting railway rolling stock.
Hence, it is necessary to provide cables for use in railway environments which minimize 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.
European Standard series EN 50264, EN 50306 and EN 50382 specify cables, which, in the event of
fire, will limit risk to people and improve the safety on railways in general. They cover cables based on
halogen free materials, for use in railway rolling stock.
A separate European Standard, the EN 50264 series covers cables for similar applications up to
3,6/6 kV rating with a conductor temperature at 90 °C, but with standard wall and medium wall
thicknesses of both insulation and sheath, and provides for a maximum conductor size of 400 mm .
A separate European Standard, the EN 50382 series covers cables for similar applications up to
3,6/6 kV rating with a conductor temperature at 120°C and 150°C, and provides for a maximum
conductor size of 400 mm .
The EN 50306 series covers a range of sheathed and unsheathed cables with thin wall insulation, and
is restricted to a rating of 300 V to earth and a maximum conductor size of 2,5 mm .
This document gives particular test methods applicable to the cables at present covered by the
EN 50264 series, EN 50306 series and EN 50382 series.
1 Scope
This document specifies special test methods applicable to cables, and their constituent insulating and
sheathing materials, for use in railway rolling stock. Such cables are specified in the various parts of
the EN 50264 series, EN 50306 series and EN 50382 series.
Other test methods required for railway rolling stock cables and their insulating and sheathing
materials are listed in Annex A.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
EN 50264-1, Railway applications - Railway rolling stock power and control cables having special fire
performance - Part 1: General requirements
EN 50306-1, Railway applications - Railway rolling stock cables having special fire performance - Thin
wall - Part 1: General requirements
EN 50382-1, Railway applications - Railway rolling stock high temperature power cables having
special fire performance - Part 1: General requirements
EN 60216-1, Electrical insulating materials - Thermal endurance properties - Part 1: Ageing
procedures and evaluation of test results
EN 60228, Conductors of insulated cables
EN 60332-3-25, Tests on electric and optical fibre cables under fire conditions - Part 3-25: Test for
vertical flame spread of vertically-mounted bunched wires or cables - Category D
EN 60754-1, Test on gases evolved during combustion of materials from cables - Part 1:
Determination of the halogen acid gas content
EN 60754-2:2014, Test on gases evolved during combustion of materials from cables - Part 2:
Determination of acidity (by pH measurement) and conductivity
EN 60811 (all parts), Electric and optical fibre cables - Test methods for non-metallic materials
EN 62230, Electric cables - Spark-test method
ISO 6349:1979, Gas analysis - Preparation of calibration gas mixtures - Permeation method
ISO 8458-2, Steel wire for mechanical springs — Part 2: Patented cold-drawn non-alloy steel wire
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 50264-1, EN 50306-1 and
EN 50382-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
4 Applicability, sampling, test-piece preparation and test conditions
4.1 Applicable tests
Tests applicable to each type of cable are given in the particular cable standard.
4.2 Classification of tests
The classification of tests is given in the general requirements of the relevant cable standard.
4.3 Sampling
The size and number of samples for each particular test is given either in this document or the
relevant cable standard.
4.4 Test-piece preparation
The preparation of test pieces shall be as described in the particular test method or in the cable
standard.
NOTE Attention is drawn to the fact that some insulation systems used for railway cables are composites
(multilayer). In such cases special preparation techniques and requirements are given in the particular cable
standard.
4.5 Test conditions
4.5.1 Ambient temperature
Tests shall be made at an ambient temperature within the range 5 °C to 35 °C, unless otherwise
specified in the details for the particular test.
4.5.2 Tolerance on temperature values
The tolerances which shall apply to the temperature values are given in Table 1.
Table 1 — Tolerances for temperature values
Specified Tolerance
temperature (T)
°C °C
−40 ≤ T ≤ 0 ±2
0 < T ≤ 50 According to relevant clause
50 < T ≤ 150 ±2
T > 150 ±3
4.5.3 Frequency and waveform of power frequency test voltages
Unless otherwise specified, the test voltage shall be a.c. 49 Hz to 61 Hz of approximately sine-wave
form; the ratio peak value/r.m.s. value being equal to √2 with a tolerance of ± 7 %.
The values quoted are r.m.s. values.
4.5.4 Pre-conditioning
Unless otherwise stated the tests shall be carried out not less than 16 h after the extrusion or cross-
linking, if any, of the insulating or sheathing compounds.
5 Mechanical tests
5.1 Impact test at low temperature
The impact test in accordance with EN 60811-506:2012, 8.5 shall be used except that the mass of
hammer, intermediate test piece and height of drop shall be as given in Table 2.
Table 2 — Parameters for impact test at low temperature
Cable Mass of Mass of intermediate Height of
diameter (D) hammer test piece drop
mm g g mm
D ≤ 15 1 000 200 100
15 < D ≤ 25 1 500 200 150
D > 25 2 000 200 200
The inside and outside of the sheath and the insulation of unsheathed cables shall then be examined
with normal or corrected vision, without magnification. The insulation of sheathed cables shall be
examined on the outside only.
5.2 Abrasion resistance
The test shall be carried out at a temperature of (20 ± 5) °C, using a machine similar to that shown in
Figure 1.
The cutting edge shall be either a polished steel spring wire needle of (0,45 ± 0,01) mm diameter of
material according to ISO 8458-2, held in a suitable support (Figure 1 b)), or a rectangular shaped
steel blade (Figure 1 a)) mounted at 90° to the axis of the cable. The setting shall be arranged so as to
wear the surface of the core or cable lengthwise over a distance of 10 mm to 20 mm, with a frequency
of (55 ± 5) cycles per minute. The machine shall be fitted with a counter which shall stop automatically
when the cutting edge touches the conductor or electrical screen.
For cables of diameter less than or equal to 6 mm the needle shall be used, and for cables with
diameter greater than 6 mm the steel blade shall be used, unless otherwise specified in the particular
cable standard.
The load on the cutting edge shall be defined in the cable standard.
The test specimen shall consist of a single 0,75 m sample of core or cable.
The test specimen shall be held securely on the plate by 2 cable clamps.
Each test specimen shall undergo four tests. After each single test it shall be moved approximately
100 mm and turned by a 90° angle, clockwise.
In the case of 2 core cables, 3 core cable or those cables not substantially circular, the cutting edge
should be applied to the highest points on the circumference of the cable.
Each test is finished when the cutting edge touches the conductor or electrical screen.
The measure of abrasion resistance shall be the average value of the number of cycles in the four
tests.
Dimensions in millimetres
a) Detail X b) Detail Y
(edges not rounded; free of burr)
Key
1 Stroke generator 7 Fastening screw
2 Stroke 8 Blade reamer
3 Loading weight 9 Shoulder of sufficient depth to
clear insulation
4 Clamp
5 Test specimen 10 Cutting edge - needle
6 Supporting plate 11 Cable under test
Figure 1 — Test arrangement for abrasion of insulation and sheath
5.3 Notch propagation
Three samples of the cable shall be notched, to a depth of 0,05 mm of the insulation or sheathing, at
four points equally spaced with respect to one another around the circumference and 25 mm apart
along the length, and in a plane mutually perpendicular to the conductor.
In the case of 2 core cable, 3 core cable or those cables not substantially circular, the notches should
be made at the highest points on the circumference of the cable.
One of the samples shall be conditioned at −15 °C, one at ambient temperature and one at 85 °C, in
all cases for 3 h, after which time they shall be wound on to a mandrel, (3 ± 0,3) times the minimum
specified diameter of the cable, whilst at the conditioning temperature. The notched sample shall be
wrapped around the mandrel such that at least one notch is on the outside of the wrapped cable.
The sample shall be allowed to return to ambient temperature and then subjected to the voltage test
given in 6.2 but at half the rated voltage U .
5.4 Pliability (only applicable for cable in according to EN 50306 series)
From a single coil of cable cut consecutive test specimen lengths, each of approximately 200 mm.
Suspend each specimen vertically for 24 h in an oven with a mass attached to its free end. The
applied mass and oven temperature shall be as stated in the cable specification. Immediately after
removal from the oven, store the specimens at the temperature, relative humidity and period of time
specified in the cable specification.
Test each specimen using the test rig shown in Figure 2; the diameter of the mandrel in the test rig
shall be as the minimum bend diameter unless specified in the cable specification. Gradually apply a
mass to the cable, at the position shown in Figure 2, sufficient to bend the cable downwards through
(90 ± 1)°.
Ensure that the specimen remains in this position for 5 min and record the mass. After this time,
remove the mass and allow the specimen to recoil towards its original position. At a time 5 min after
removal of the mass, record the recoil angle.
Dimensions in millimetres / scale in degrees
Key
1 Clamp
2 Mandrel
3 Test specimen
4 Mass container
5 Recoil angle
Figure 2 — Pliability test rig
5.5 Strippability and adhesion of insulation (only applicable for cable in according to
EN 50306 series)
5.5.1 Strippability
Stripping of 5 mm of insulation from each end of a 50 mm sample shall be easily carried out with
normal stripping pliers.
5.5.2 Adhesion
Three test specimens, each of 50 mm length, shall be cut at regular intervals from a test sample of
3 m of core or cable.
On each specimen the insulation shall be cut 5 mm and 30 mm from one end. The insulation shall be
stripped from the cuts to each end, so that insulation is left intact in-between the two cuts. The
conductor shall then be passed through a calibrated hole the diameter of which is that of the conductor
+ 0,05 mm (see Figure 3).
Using a pulling speed of (100 ± 10) mm/min a force shall be applied to the conductor until it slips
inside the insulation. The force (F) required to produce the slippage shall be recorded.
Dimensions in millimetres
Figure 3 — Assembly for adhesion test
5.6 Dynamic cut-through (only applicable for cable in according to EN 50306 series)
A tensile tester (or equivalent apparatus) shall be operated in a compression mode and shall be
equipped with a means to record the force necessary to drive the needle cutting edge (see
Figure 1 b)) through the insulation or sheath of a finished sample of cable. A low voltage detection
circuit, designed to stop the tester when the edge cuts through the cable insulation or sheath and
contacts the conductor or electrical screen, shall be attached.
Carry out the test at the temperature specified in the individual cable specification. The force on the
cutting edge driving it through the insulation or sheath shall be increased at the constant rate as
specified in the product standard until contact with the conductor or metallic screen occurs. Perform
four tests on each test sample, and record the force measured at electrical contact. Move the sample
forward a minimum of 25 mm and rotate 90° clockwise between each test.
In the case of 2 core cables, 3 core cable or those cables not substantially circular, the cutting edge
should be applied to the highest points on the circumference of the cable.
The average of the four results shall not be less than the specified minimum.
6 Electrical tests
6.1 Electrical resistance of conductors
The electrical resistance of each conductor shall be measured on a sample of cable of at least 1 m in
length, and the length of this sample shall be measured.
If necessary a correction to 20 °C and to a length of 1 km shall be obtained by the formula:
1 000
254, 5
RR=××
20 t
234, 5+ t L
Where
t = temperature of the sample at the moment of measurement, in degrees Celsius;
R = resistance at 20 °C, in ohm/kilometre;
Rt = resistance of L metres of cable at t °C in ohm;
L = measured length of the cable, in metres
The measured resistance shall not exceed the value in EN 60228 or the relevant cable standard.
6.2 Voltage test on completed cable
6.2.1 Cable without metallic layer
If the cable has no metallic layer, a sample of the cable as delivered shall be immersed in water for a
minimum period of 1 h. The length of the sample, the temperature of the water and the duration of
application of voltage shall be as given in the cable specification.
The voltage shall be applied in turn between each conductor and all the others connected together
and to the water.
6.2.2 Cable with one or more metallic layers
a) If the cable has a metallic layer, a sample of the cable shall be taken of the length defined in the
cable specification.
The voltage shall be applied in turn between each conductor and all the others connected
together and to the metallic layer.
The voltage and the duration of its application are given for each case in the cable specification.
b) If the cable has more than one screened and sheathed unit a sample of the complete cable shall
be taken of the length defined in the cable specification.
The voltage shall be applied in turn between each screen and all other screens and conductors
connected together.
The voltage and the duration of its application are given for each case in the cable specification.
6.3 Voltage test on sheath
The test shall be made on sheathed cable where there is a metallic screen or braid under the sheath.
A length of complete cable shall be immersed in water, and an AC or a DC voltage applied between
the metallic screen or braid and the water.
The sample length, test temperature, voltage level and duration of its application shall be as given in
the particular cable standard.
6.4 Insulation resistance
6.4.1 Test at ambient temperature
The test shall be made on the core samples, 5 m long, previously submitted to the test described in
6.2.1.
The sample shall be immersed in water at ambient temperature; a length about 0,25 m at each end of
the sample being kept above the water. The duration of immersion shall be a minimum of 1 h.
A DC voltage of between 80 V and 500 V shall be then applied between the conductor and the water.
The insulation resistance shall be measured one minute after application of the voltage and this value
shall be corrected to 20 °C and related to 1 km.
6.4.2 Test at elevated temperature
The test shall be made on the core samples, 5 m long.
The sample shall be immersed in water previously heated to 90 °C; a length of about 0,25 m at each
end of the sample being kept above the water. The duration of immersion shall be a minimum of 1 h.
A DC voltage of between 80 V and 500 V shall then be applied between the conductor and the water.
The insulation resistance shall be measured one minute after application of the voltage and this value
shall be related to 1 km.
6.5 Spark test
6.5.1 General
This test shall be carried out as a routine test with equipment according to EN 62230 on delivery
lengths or on manufacturing lengths before cutting them into delivery lengths.
The test shall be carried out either on insulated cores or on the sheath of cable where there is a
metallic screen or braid under the sheath.
6.5.2 Method
Test requirements: The cable shall withstand the test voltage specified in the particular cable
standard without failure of the insulation or sheath as appropriate. The spark test equipment shall
detect a puncture in the insulation or sheath having a diameter equal to or greater than half of the
specified insulation or sheath thickness. The recovery time of the spark tester shall be not greater than
one second.
Test voltage: The voltage applied by the spark tester may be power frequency AC, DC, high
frequency or of other form.
The magnitude and the presence of the voltage shall be such that with the electrode system employed
and at the speed employed for the passage of the cable through the spark tester the test requirements
are effectively met.
The reference method to be used to establish the efficacy of the spark testing equipment is given in
Annex B.
6.6 Surface resistance
The test specimen shall be prepared as follows.
Each specimen shall have two annular electrodes fitted as shown in Figure 4. The two electrodes shall
consist of copper wire with a diameter of about 1,8 mm and they shall be arranged in the centre part of
the specimen with their internal windings about 50 mm from each other. When positioning the
electrodes it is essential to avoid any serious indentation of the wire into the protective cover.
The specimens, fitted with their electrodes, shall be immersed in water held at (20 ± 5) °C for 4 h with
the ends of the specimen protruding by about 50 mm above the level of the water.
Upon completion of this operation, the specimens shall be removed from the water and excess water
removed from their surfaces.
The specimens prepared in this way shall be immediately subjected to 2,0 kV AC applied between the
electrodes. The leakage current shall be measured, using an appropriate ammeter, between the two
electrodes after 30 s voltage application.
Immediately after the determination of the leakage current, the voltage applied between the electrodes
shall be increased at a constant rate of 100 V/s until breakdown occurs or the voltage limit given in the
particular specification is exceeded.
Dimensions in millimetres
Key
1 Copper wire
2 Test specimen
3 Water level
Figure 4 — Arrangement of electrodes for test sample
6.7 DC stability
A test specimen of minimum length of 5 m of cable shall be immersed in distilled water containing 3 %
NaCl. At least 300 mm of additional cable shall protrude at each end. The salt solution shall be
maintained at an elevated temperature of (85 ± 2) °C for (240 ± 2) h, and the specified voltage applied
between the conductor and the salt solution with the conductor at the negative potential. The test shall
then be repeated, using a new test specimen, with the conductor at the positive potential.
The current flowing in the circuit shall be measured periodically throughout the test at intervals not
greater than 24 h. Continuous measurement is preferred, if possible.
The current measurement data shall be plotted in the form of a current versus time curve and shall
indicate an approach to a period of stability.
NOTE A period of stability is, for instance, less than 10 % increase in current leakage averaged over any
24 h period (this is subject to review in the light of practical experience).
On completion of the immersion, the cables shall be removed from the salt solution and subjected to
the voltage test specified in 6.2 except that the test voltage shall be the rated voltage (U) of the cable,
unless otherwise specified.
6.8 Dielectric strength
5 m of cable sample shall be immersed in water for a period as given in the cable standard,
maintained at a temperature of (20 ± 5) °C with at least additional lengths of 150 mm protruding at
each end. The voltage test specified in 6.2 shall be applied for 1 min between the conductor and the
water. The test voltage shall be as specified in the cable specification. Immediately afterwards the
voltage shall be increased by 500 V every 30 s until a disruptive discharge occurs.
The recorded value shall exceed the specified minimum.
7 Ageing and thermal tests
7.1 Compatibility
Samples of completed cables shall be aged in accordance with the time and temperatures given in the
appropriate cable specification. The testing shall be in accordance with EN 60811-401 for single layer.
For multi-layer insulating systems special techniques are given in the particular cable standard (see
4.4).
7.2 Long term ageing
7.2.1 General
This test method provides a standardized test and procedure for determining the 20 000 h lifetimes of
insulation and sheath materials. The end point selected is 50 % elongation at break. A brief
explanation of the significance and use of the test is given in Annex C.
To give a value representative of supplied cables, and to provide comparative data, tests for insulation
shall be carried out on samples of insulated cores. Sheath shall be taken from a cable of sufficient size
so that, after buffing to remove any indentations, the sample conforms to the requirements of
EN 60811-501 (multi-layered systems will therefore require large cross-sections to be tested). This
allows customers, if required, to confirm performance on supplied cables. Ageing performance
demonstrated on small cross section cables it is deemed to be representative cables with the same
design and materials.
7.2.2 Summary of test method
Three or four sets of test specimens of a given sample of insulated wire are exposed to several fixed
temperatures. From time to time a set of samples is removed and each specimen is wrapped on a 1
D
mandrel to simulate a flexing stress equal to 50 % and then immersed in a water bath where it is
subject to a voltage test. A 6 D or values of Table 3 mandrel may be used as an alternative, as this
represents the minimum bending radius allowed for installation. Specimens are removed until such
time that failure occurs.
The life data at different temperatures are analysed on the basis of the Arrhenius equation which
relates exposure time to failure to the reciprocal of the absolute temperature of exposure. The method
is based on EN 60216-1.
An initial screening test at 180°C ± 2°C is used to determine the approximate rating of the cable. 45
Samples are placed in the oven, after 4 days the first 3 samples are tested. Each day 3 samples are
removed and tested until failure occurs or 50 % elongation is no longer achieved. Based on the results
of the screening test sufficient sets of test specimens of a given sample of insulated wire or sheath are
exposed at several fixed temperatures with the lowest temperature selected such that at least 5000 h
will be needed for the end point to be reached. At appropriate intervals samples are removed and
tested, either by wrapping the sample around a 1D mandrel or around itself to induce 50 % strain,
followed by electrical tests, or in the case of sheathing by tensile testing. Using the methods described
in EN 60216-1 the time to failure at different temperatures are used to create an Arrhenius plot to
determine the 20000h / 50 % elongation at break rating. Previous convention dictates that at least
20°C higher rating is needed than the designated continuous use temperature. Cable in accordance
with EN 50264-1 designated for 90°C continuous use requires insulation and sheath to achieve at
least 110°C/20000 h.
7.2.3 Apparatus
The ageing shall be carried out in a circulating air oven, meeting the general requirements of
EN 60811-401 and capable of operating at the required temperature. The vertical internal dimension
of the oven shall be at least 500 mm.
A rack shall be provided for holding insulated wire specimens. A simple one can consist of 6 mm rods
located horizontally approximately 25 mm below the top of the chamber. These can be mounted as a
part of the chamber or as a removable rack carrying the specimens.
Stabilizing weights, each with a hook, shall be provided for holding insulated wire specimens straight
in the oven during ageing. The appropriate weight size is about one-half of the wrapping test weight
shown in Table 3. It is suggested that this weight also has a hook on the bottom so that the additional
weight required for the mandrel wrap can be added without removing the stabilizing weight.
The ageing shall be carried out in a circulating air oven, meeting the general requirements of
EN 60811-401 and capable of operating at the required temperature.
7.2.4 Method
7.2.4.1 Test specimens
Each specimen shall be a 300 mm to 400 mm length of insulated wire whose insulation is free from
visible imperfections. It is convenient to strip approximately 6 mm of insulation at each end and apply
a lug from which the weights can be suspended. The lug shall be of a type that not only contacts the
conductor but also clamps the insulation to prevent shrinkage with temperature exposure. The initial
selection shall be using a mandrel of the same diameter as the cable being tested to introduce 50 %
strain. The test after ageing may be performed with values of Table 3, or at the minimum specified
bending radius allowed for installation. The Report shall state on which size of mandrel the ageing was
carried out.
NOTE This would allow some currently conforming products to be tested.
7.2.4.2 Temperature selection and exposure
The selection of temperatures for test shall be achieved by adding 20 °C to the expected 20 000 h
temperature as determined by the initial screening test for the lowest temperature and two further
temperatures at 10 °C to 20 °C successive steps. If the average life at the highest test temperature is
found to be less than 100 h, too high a test temperature has been selected and the data should be
discarded. The test should be repeated at a lower temperature.
Extrapolation to a temperature should not exceed 25 °C below the lowest ageing test temperature. If
extrapolation beyond 25 °C is required, an additional series of tests shall be made at an even lower
temperature. If, in addition, the average life found at the lowest test temperature is less than 5000 h,
tests shall be made at lower temperatures until at least 5000 h average life data are achieved.
The initial screening test will determine how many days are required to drop the elongation at break
below 50 % at 180°C. Assuming the halving interval is 10°C a cable having the required
110°C/20000h/50 % will take approximately 6,5 days to fail. Cables having higher temperature ratings
will take longer to fail.
7.2.4.3 Wrapping procedure
After each period of exposure remove the gro
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Frequently Asked Questions
SIST EN 50305:2020 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Railway applications - Railway rolling stock cables having special fire performance - Test methods". This standard covers: This document specifies special test methods applicable to cables, and their constituent insulating and sheathing materials, for use in railway rolling stock. Such cables are specified in the various parts of the EN 50264 series, EN 50306 series and EN 50382 series. Other test methods required for railway rolling stock cables and their insulating and sheathing materials are listed in Annex A.
This document specifies special test methods applicable to cables, and their constituent insulating and sheathing materials, for use in railway rolling stock. Such cables are specified in the various parts of the EN 50264 series, EN 50306 series and EN 50382 series. Other test methods required for railway rolling stock cables and their insulating and sheathing materials are listed in Annex A.
SIST EN 50305:2020 is classified under the following ICS (International Classification for Standards) categories: 13.220.40 - Ignitability and burning behaviour of materials and products; 29.060.20 - Cables; 45.060.01 - Railway rolling stock in general. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN 50305:2020 has the following relationships with other standards: It is inter standard links to SIST EN 50305:2002, SIST EN 50305:2002. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase SIST EN 50305:2020 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of SIST standards.
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