Non electrical test methods for low voltage energy cables

EN 50396 contains non-electrical test methods required for the testing of harmonized low voltage energy cables, especially those rated at up to and including 450/750 V. NOTE 1   A description of the origin of these test methods and of the background to the EN are given in the Introduction and Annex A. The particular cable standard dictates the tests which need to be performed on the relevant cable type. It also specifies whether the specific test is a type test (T), a sample test (S) or a routine test (R) for the particular cable type. NOTE 2   T, S and R are defined in the relevant cable standard. The requirements to be met during or after the test are specified for the particular cable type in the relevant cable standard. However, some test requirements are obvious and universal, such as the fact that no cracks shall occur during ozone test, and these are stated in the particular test method. Test methods for use specifically in utility power cables are not covered by this EN. They can be found in HD 605. Test methods for use specifically in communications cables are the responsibility of CENELEC TC 46X. At present such test methods are given in EN 50289 (series).

Nicht-elektrische Prüfverfahren für Niederspannungskabel und -leitungen

EN 50396 enthält nicht-elektrische Prüfverfahren für die Prüfung von harmonisierten Niederspannungskabeln und –leitungen, insbesondere für die mit Nennspannungen bis 450/750 V. ANMERKUNG 1    Eine Beschreibung der Herkunft dieser Prüfverfahren und des Hintergrunds dieser EN findet sich in der Einleitung und im Anhang A. Die jeweilige Kabel- und Leitungsnorm bestimmt die Prüfungen, die an der entsprechenden Kabel- und Leitungsbauart durchgeführt werden müssen. Sie legt ebenfalls fest, ob die spezielle Prüfung eine Typ- (T), Auswahl- (S) oder Stückprüfung (R) für die jeweilige Kabel- oder Leitungsbauart ist. ANMERKUNG 2   T, S und R sind in der zutreffenden Kabel- und Leitungsnorm festgelegt. Die Anforderungen, die während oder nach der Prüfung erfüllt werden müssen, sind für die jeweilige Kabel- oder Leitungsbauart in der zugehörigen Kabel- oder Leitungsnorm festgelegt. Einige Prüfanforderungen sind offensichtlich und allgemeingültig, zum Beispiel die Tatsache, dass während der Ozonprüfung keine Risse auftreten dürfen; diese Anforderungen sind im jeweiligen Prüfverfahren niedergelegt. Prüfverfahren, die speziell bei Energieversorgungskabeln anzuwenden sind, werden durch diese EN nicht abgedeckt. Sie sind in HD 605 zu finden. Prüfverfahren, die speziell bei Kommunikationskabeln anzuwenden sind, liegen im Zuständigkeitsbereich von CENELEC TC 46X. Zur Zeit sind diese Prüfverfahren in EN 50289 (Reihe) angegeben.

Méthodes d'essais non électriques pour les câbles d'énergie basse tension

La EN 50396 contient les méthodes d’essais non électriques prescrites pour l’essai des câbles d’énergie basse tension harmonisés, en particulier ceux de tension assignée au plus égale à 450/750 V. NOTE 1   Une description de l’origine de ces matériaux et du fondement de la EN est donné dans l’introduction et dans l’Annexe A. La norme de câble particulière spécifie les essais qui doivent être effectués sur le type de câble correspondant. Elle précise également si l’essai spécifique est un essai de type (T), un essai sur prélèvements (S) ou un essai individuel (R) pour le type de câble particulier. NOTE 2   T, S et R sont définis dans la norme de câble correspondante. Les exigences à satisfaire pendant ou après l’essai sont indiquées pour le type de câble particulier dans la norme de câble correspondante. Cependant, certaines exigences d’essai sont évidentes et universelles, comme le fait qu’aucune craquelure ne doit se produire pendant l’essai à l’ozone. Ces exigences sont indiquées dans la méthode d’essai particulière. Les méthodes d’essai à utiliser spécifiquement pour les câbles de distribution d’énergie ne sont pas couvertes par la présente EN. Elles figurent dans le HD 605. Les méthodes d’essai à utiliser spécifiquement pour les câbles de communications sont de la responsabilité du CENELEC TC 46X. Actuellement, de telles méthodes sont indiquées dans la EN 50289 (série).

Metode za preskušanje neelektričnih lastnosti nizkonapetostnih energetskih kablov

General Information

Status
Published
Publication Date
30-Nov-2005
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Dec-2005
Due Date
01-Dec-2005
Completion Date
01-Dec-2005

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SLOVENSKI SIST EN 50396:2005

STANDARD
december 2005
Metode za preskušanje neelektričnih lastnosti nizkonapetostnih energetskih
kablov
Non electrical test methods for low voltage energy cables
ICS 29.060.20 Referenčna številka
SIST EN 50396:2005(en)
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

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

EUROPEAN STANDARD EN 50396
NORME EUROPÉENNE
EUROPÄISCHE NORM August 2005

ICS 29.060.20 Partially supersedes HD 21.2 S3:1997 + A1:2002 &
HD 22.2 S3:1997 + A1:2002


English version


Non electrical test methods for low voltage energy cables


Méthodes d'essais non électriques  Nicht-elektrische Prüfverfahren
pour les câbles d'énergie basse tension für Niederspannungskabel und -leitungen









This European Standard was approved by CENELEC on 2005-07-01. 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 Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


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

Ref. No. EN 50396:2005 E

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

EN 50396:2005 - 2 -
Foreword
This European Standard was prepared by the Technical Committee CENELEC TC 20, Electric
cables. In accordance with the decision of TC 20 at its Setubal meeting (June 2004), the text
of the draft was submitted to the formal vote. It was approved by CENELEC as EN 50396 on
2005-07-01.
This European Standard, together with EN 50395:2005, supersedes HD 21.2 S3:1997 +
A1:2002 and HD 22.2 S3:1997 + A1:2002.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2006-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2008-07-01
__________

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– 3 – EN 50396:2005
Contents
Page
1 Scope .5
2 Normative references .5
3 General test requirements.6
3.1 Sampling .6
3.2 Pre-conditioning .6
3.3 Test temperature.6
3.4 Test values.6
4 General test methods for dimensions .6
4.1 Measurement of insulation thickness .6
4.2 Measurement of sheath thickness for circular cables.7
4.3 Measurement of sheath thickness for flat cables .7
4.4 Measurement of overall dimensions and ovality.8
5 Tests relating to marking and colouring .9
5.1 Durability.9
5.2 Green-and-yellow measurement .9
6 Tests for mechanical strength of cables .11
6.1 Static flexibility test .11
6.2 Two pulley flexing test.13
6.3 Three pulley flexing test .18
6.4 Bending test .19
6.5 Kink test.20
6.6 Wear resistance test.23
6.7 Snatch test.24
6.8 Test for separation of cores.25
7 Tests for resistance to heat .25
7.1 Test of the resistance to hot particles .25
7.2 Test for resistance to heat of textile braids .26
8 Chemical and related tests.28
8.1 Ozone resistance test.28
8.2 Solderability test for plain conductors .30
9 Tests specific to extensible leads .32
9.1 Extension test .32
9.2 Endurance test .33
9.3 Tests under fire conditions .35
10 Tests specific to thermoplastic polyurethane sheath.35
10.1 Determination of the saponifìcation value of the polyurethane sheath.35
10.2 Tear resistance test.37
10.3 Water resistance .38
Annex A (informative) Source of non-electrical test methods in EN 50396.40
Annex B (normative) Rounding of numbers .41
Annex C (informative) Table for the calculation of α.42
Annex D (normative) Special national conditions.44

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EN 50396:2005 - 4 -
Bibliography.45

Figure 1 - Measurement of sheath thickness (flat cable) .8
Figure 2a - Measurement of the green-and-yellow proportion.9
Figure 3 - Static Flexibility Test.12
Figure 4 - Flexing apparatus .17
Figure 5 - Modified carrier "C".19
Figure 6 - Bending Test Apparatus.20
Figure 7 - Kink test apparatus .22
Figure 8 - Arrangement for wear-resistance test. .24
Figure 9 - Device for testing resistance to hot particles.26
Figure 10 - Apparatus for the test for resistance to heat of textile braid.27
Figure 11 - Example of a clamping device.30
Figure 12 - Modified flexing apparatus for extensible leads .34
Figure 13 - Modified flexing apparatus for short extensible leads .34
Figure 14 - Test piece.38
Figure 15 - Test piece before being placed in the jaws of the tensile testing machine .38

Table 1a - Mass of weight and diameter of pulleys – thermoplastic cables .14
Table 1b - Mass of weight and diameter of pulleys – Crosslinked cables.16
Table 2a - Current loadings – Thermoplastic cables.17
Table 2b - Current loadings – Crosslinked cables .17
Table 3 - Current loading and diameter of pulley wheels .18
Table 4 - Tensile force exerted by the weight and test currents.21
Table for the calculation of α (continued) .43
Table 1a - Mass of weight and diameter of pulleys – thermoplastic cables .44
Table 1b - Mass of weight and diameter of pulleys – Crosslinked cables.44
Table 2a - Current loadings – Thermoplastic cables.44
Table 2b - Current loadings – Crosslinked cables .44

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– 5 – EN 50396:2005
Introduction
EN 50396 contains the non-electrical test methods that are used for harmonized low voltage
energy cables. These non-electrical test methods include all those previously contained in
HD 21 and HD 22. Annex A gives a comparison between the original location of each test
method and its place in this new EN.
The content of EN 50396 is not, and will not be, restricted only to test methods for cables to
HD 21 and HD 22. Other test methods for harmonized LV cables may be included.
Furthermore, the use of test methods in EN 50396 for cables outside HD 21 and HD 22 is not
prohibited, but it is strongly recommended that expert advice be taken before such use, or
before any proposal for incorporation into another standard.
1 Scope
EN 50396 contains non-electrical test methods required for the testing of harmonized low
voltage energy cables, especially those rated at up to and including 450/750 V.
NOTE 1  A description of the origin of these test methods and of the background to the EN are given in the
Introduction and Annex A.
The particular cable standard dictates the tests which need to be performed on the relevant
cable type. It also specifies whether the specific test is a type test (T), a sample test (S) or a
routine test (R) for the particular cable type.
NOTE 2  T, S and R are defined in the relevant cable standard.
The requirements to be met during or after the test are specified for the particular cable type
in the relevant cable standard. However, some test requirements are obvious and universal,
such as the fact that no cracks shall occur during ozone test, and these are stated in the
particular test method.
Test methods for use specifically in utility power cables are not covered by this EN. They can
be found in HD 605.
Test methods for use specifically in communications cables are the responsibility of
CENELEC TC 46X. At present such test methods are given in EN 50289 (series).
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
Publication Year Title
EN 60332-1-2 2004 Tests on electric and optical fibre cables under fire conditions -
Par1-2: Test for vertical flame propagation for a single insulated
wire or cable - Procedure for 1 kW pre-mixed flame
EN 50395 2005 Electrical test methods for low voltage energy cables
EN 60695-11-5 2005 Fire hazard testing - Part 11-5: Test flames - Needle-flame test
method - Apparatus, confirmatory test arrangement and
guidance

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

EN 50396:2005 - 6 -
EN 60811-1-1 1995 Insulating and sheathing materials of electric and optical cables -
A1 2001 Common test methods - Part 1-1: General application -
Measurement of thickness and overall dimensions - Tests for
determining the mechanical properties
EN 60811-1-2 1995 Insulating and sheathing materials of electric and optical cables -
A2 2000 Common test methods - Part 1-2: General application - Thermal
ageing methods
EN 60811-2-1 1998 Insulating and sheathing materials of electric and optical cables -
A1 2001 Common test methods - Part 2-1: Methods specific to
elastomeric compounds - Ozone resistance test, hot set and
mineral oil immersion test
3 General test requirements
3.1 Sampling
If a marking is indented in the insulation or sheath, the samples used for the tests shall be taken so as to
include such marking.
For multicore cables, except for the test in 5.1, not more than three cores (of different colours, if
available) shall be tested unless otherwise specified.
3.2 Pre-conditioning
All 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.
3.3 Test temperature
Unless otherwise specified in the details for the particular test, tests shall be made at an
ambient temperature of (20 ± 15) °C.
3.4 Test values
Full test conditions (such as temperatures, durations, etc.) and full test requirements are not
specified in this standard; it is intended that they should be specified by the standard dealing
with the relevant type of cable.
Any test requirements which are given in this standard may be modified by the relevant cable
standard to suit the needs of a particular type of cable.
4 General test methods for dimensions
4.1 Measurement of insulation thickness
4.1.1 Procedure
The thickness of insulation shall be measured in accordance with 8.1 of EN 60811-1-1.
Three samples shall be taken from the cable; each sample shall be separated from the next by a
distance of at least 1 m.
Conformity shall be checked on each core.

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– 7 – EN 50396:2005
If withdrawal of the conductor is difficult, it shall be stretched in a tensile testing machine or the piece of
core shall be loosened by stretching or some other suitable means that does not damage the insulation.
The cores of flat non-sheathed cords shall not be separated.
4.1.2 Evaluation of results
The mean of the 18 values (expressed in millimetres) obtained from the three pieces of insulation from
each core shall be calculated to two decimal places and rounded off as given in Annex B, and this shall
be taken as the mean value of the thickness of insulation.
The lowest of all values obtained shall be taken as the minimum thickness of insulation at any place.
4.2 Measurement of sheath thickness for circular cables
4.2.1 Procedure
The thickness of the sheath for circular cables shall be measured in accordance with 8.2 of
EN 60811-1-1.
One sample of cable shall be taken from each of three places, separated by at least 1 m.
For flat cords the measurements shall be carried out in accordance with 4.3.
4.2.2 Evaluation of results
The mean of all the values (expressed in millimetres) obtained from the three pieces of sheath shall be
calculated to two decimal places and rounded off as given in Annex B, and this shall be taken as the
mean value of the thickness of sheath.
The lowest of all values obtained shall be taken as the minimum thickness of sheath at any place.
4.3 Measurement of sheath thickness for flat cables
4.3.1 Measuring equipment
A measuring microscope or a profile projector shall be used, each instrument being capable of at least
10 x magnification. The equipment shall have an accuracy of 0,01 mm. In cases of dispute a microscope
allowing a reading with an accuracy of 0,01 mm or a profile projector of at least 20 x magnification shall
be used.
4.3.2 Preparation of test pieces
One sample of cable shall be taken from each of three places, separated by at least 1 m.
After all materials inside the sheath have been removed, a test piece shall be prepared from each
sample by cutting with a suitable device (sharp knife, razor blade, etc.) a slice of sheath along a plane
perpendicular to the longitudinal axis of the cable. If the sheath carries an indented marking, the test
piece shall be taken so as to include such marking.
4.3.3 Measuring procedure
The test piece shall be placed under the measuring equipment with the plane of the cut perpendicular to
the optical axis.
Measurements shall be taken on lines approximately parallel to the minor axis and on the major axis of
the cross section, at the position of each core, as shown in Figure 1.

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EN 50396:2005 - 8 -
The thinnest place on the sheath shall be measured. Where this does not coincide with one of the
designated measurement points shown in Figure 1, it shall be substituted for the closest such point, to
give a total of six measurements.
The measurements shall be made in millimetres to two decimal places.
4.3.4 Evaluation of results
The mean of all the values (expressed in millimetres) obtained from the three pieces of sheath shall be
calculated to two decimal places and rounded off as given in Annex B, and this shall be taken as the
mean value of the thickness of sheath.
The lowest of all values obtained shall be taken as the minimum thickness of sheath at any place.

1

Key
1 minimum thickness
Figure 1 - Measurement of sheath thickness (flat cable)

4.4 Measurement of overall dimensions and ovality
4.4.1 Overall dimensions
4.4.1.1 Procedure
The measurement of the overall diameter of any circular cable and of the overall dimensions of flat
cables with a major dimension not exceeding 15 mm shall be carried out in accordance with 8.3 of
EN 60811-1-1.
The three samples taken in accordance with 4.1.1, 4.2.1 or 4.3.2 shall be used.
For the measurement of flat cables with a major dimension exceeding 15 mm, a micrometer, a profile
projector or similar equipment shall be used.
4.4.1.2 Evaluation of results
The mean of the values obtained shall be taken as the mean overall dimensions.

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– 9 – EN 50396:2005
4.4.2 Procedure for ovality measurement
For checking the ovality of circular sheathed cables, two measurements shall be made at the same
cross-section of the cable, covering the maximum and minimum values.
5 Tests relating to marking and colouring
5.1 Durability
The durability of printed marking or of colour shall be checked by trying to remove the
marking or colour by rubbing lightly 10 times with a piece of cotton wool or cloth soaked in
water.
5.2 Green-and-yellow measurement
5.2.1 General
This method is not appropriate where the colour marking forms a spiral on the insulation.
5.2.2 Procedure
Two samples of the green-and-yellow core each approximately 100 mm in length, shall be
taken at least 2 m one from the other.
Measure a 15 mm length from each of the samples and cut three sections of insulation from
each 15 mm test piece length, one from each end and one from the centre.
Project a 10 X minimum magnified image of each cross section on to a ground glass screen
and make a visual estimation of the colour boundaries at the outer surface of the core.
Continue the measurement using either of the following methods.
Method 1
Measure the distance d1 and the core diameter D (Figure 2a).

Figure 2a - Measurement of the green-and-yellow proportion

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EN 50396:2005 - 10 -
Calculate the value for sine α using the formula:
d1
sin α =
D
d1 = the chord of the green segment.
D = the mean value of the diameter calculated from three measurements at different angles
Calculate the percentage (G ) of green (or yellow) using the following formula:
p
2× α
G = × 100
p
360
In order to facilitate the calculation, the table in Annex C can be used.
Method 2
Measure to the nearest degree, using a protractor placed on the magnified image, the angle
subtended at the centre of the cross section by each portion of green (or yellow if
appropriate). See Figure 2b.
Key
1 base colour 2 other colour
Figure 2b - Measurement of the green-and-yellow proportion

Calculate the percentage (G ) of green (or yellow) for each cross section using the following
p
equation:
A
T
G = × 100
p
360
A is the total sum of each of the angles of rotation through each of the portions of green (or
T
yellow if appropriate).
5.2.3 Evaluation of results
Calculate the mean of the six measurements and round to the nearest integer.
Compare the results with the requirement specified in the relevant cable standard.

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– 11 – EN 50396:2005
6 Tests for mechanical strength of cables
6.1 Static flexibility test
6.1.1 Apparatus
A sample with a length of (3 ± 0,05) m shall be tested using test apparatus similar to that shown in
Figure 3. Two clamps, A and B, shall be located at a height of at least 1,5 m above ground level.
Clamp A shall be fixed and clamp B shall move horizontally at the level of clamp A.
6.1.2 Procedure
Clamp the ends of the sample vertically so that they remain vertical during the test, one end
in clamp A, the other in the movable clamp B which shall be at a distance L = 0,20 m from
clamp A.
NOTE  The cable should take approximately the shape indicated by Figure 3 (dotted lines).
Move the movable clamp B away from the fixed clamp A until the loop formed by the cable takes the
shape, indicated in Figure 3 by the heavy outline, of the U enclosed wholly between two plumb lines
through the clamps and set up tangentially to the external generatrix of the cable. Measure the new
/
distance, L . The cable shall then be turned in the clamps by 180°, and the test repeated.
/
Calculate the mean value of L .
6.1.3 Pre-conditioning of non-conforming samples
/
Where the cable does not satisfy the requirement for L, or in the case of dispute, the test shall be
repeated after the following pre-conditioning.
Wind the sample four times on and off a reel with a diameter approximately 20 times the outer diameter
of the cable. Each time the sample shall be turned through 90°, for round cables or, in the case of flat
cables, through 180°.
After this pre-conditioning, the sample shall be subjected to the test described in 6.1.2.

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EN 50396:2005 - 12 -
L'
L = 0,20 m
A
B' B
X
X'
1
1

Key
1 plumb line
Figure 3 - Static Flexibility Test

6.1.4 Requirements
/
The requirements for the maximum distance of L shall be given in the relevant cable standard.

1,50 m

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– 13 – EN 50396:2005
6.2 Two pulley flexing test
6.2.1 General
The applicability of this test is given in the relevant cable standard.
NOTE Normally this test should not be applied to:
- tinsel cords;
- single core cables with flexible conductors for fixed wiring;
2
- multi-core flexible cables having conductors of nominal cross-sectional area greater than 2,5 mm for
2
thermoplastic cables, or greater than 4 mm for crosslinked cables;
- cables having more than 18 cores laid up in more than two concentric layers.
6.2.2 Apparatus
This test shall be carried out by means of the apparatus shown Figure 4. This apparatus consists of a
carrier C, a driving system for the carrier and four pulley wheels for each sample of cable to be tested.
The carrier C supports two pulley wheels A and B, which are of the same diameter. The two fixed pulley
wheels, at either end of the apparatus, may be of a different diameter from pulley wheels A and B, but all
four pulley wheels shall be so arranged that the sample is horizontal between them. The carrier makes
cycles of forward and backward movements over a distance of 1 m at an approximately constant speed
of 0,33 m/s between each reversal of the direction of movement.
The pulley wheels shall be made of metal. Pulley wheels with a semi-circular shaped groove shall be
used for testing circular cables and pulley wheels with a flat groove for testing flat cables. The restraining
clamps D shall be fixed so that the pull is always applied by the weight from which the carrier is moving
away. The distance from one restraining clamp to its support, while the other clamp is resting on its
support, shall be a maximum of 50 mm.
The driving system shall be such that the carrier reverses smoothly and without jerks when it changes
from one direction of movement to the other.
6.2.3 Sample preparation
A sample of flexible cable about 5 m long shall be stretched over the pulley wheels, as shown in
Figure 4, each end being loaded with a weight. The mass of this weight and the diameter of pulley
wheels A and B shall be as given for the particular cable type (Table 1a for thermoplastic cables or
Table 1b for crosslinked cables as appropriate).
6.2.4 Current loading of cores
During the flexing test the cable sample shall be loaded with the current specified in Table 2a or Table 2b
for the particular cable type as follows:
- 2 core and 3 core cables: all cores shall be loaded fully
- 4 core and 5 core cables: three cores shall be loaded fully or all cores shall be
loaded with a current of I amps, calculated according to
n
the following formula:


3

=
In I3

n
where n = number of cores
I = full current according to the particular cable type
3

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EN 50396:2005 - 14 -
The current loading shall be applied either through the electrical system used to apply the
voltage between cores specified in 6.2.5, or through a separate current generator system (e.g.
current transformers). On cores which are not loaded, a signal current shall be applied. Cables
having more than five cores shall not be loaded.
6.2.5 Voltage between cores
For two-core cables and for light, sheathed three- and four-core cables, the voltage between the
conductors shall be (230 ± 15) V a.c.
For all other cables having three or more cores, a three-phase a.c. voltage of 400 V ± 15% shall be
applied to three conductors, any additional conductors being connected to the neutral. Three adjacent
cores shall be tested; in the case of a multi-layer construction they shall be taken from the outer layer.
6.2.6 Fault detection
The flexing apparatus shall be constructed so that it will detect and stop if any of the following occur
during the flexing test:
− interruption of the test current;
− short circuit between the cores;
− short circuit between the test sample and the pulley wheels (flexing apparatus).

Table 1a - Mass of weight and diameter of pulleys – thermoplastic cables
Types of flexible cables Number Nominal Mass of Diameter of
(1)
of cross weight pulleys
(2)
cores sectional

area
 mm² kg mm
Divisible, dual-insulated cables 2 0,5 0,5 60
Light polyvinyl chloride sheathed cord 2 0,5 0,5 60
Ordinary polyvinyl chloride sheathed cord 0,75 1,0 80
Oil-resistant polyvinyl chloride sheathed 1 1,0 80
cables
1,5 1,0 80
Heat-resistant polyvinyl chloride sheathed
2,5 1,5 120
cables
3 0,5 0,5 80
0,75 1,0 80
1 1,0 80
1,5 1,0 80
2,5 1,5 120
4 0,5 0,5 80
0,75 1,0 80
1 1,0 80
1,5 1,5 120
2,5 1,5 120

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...

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