SIST EN 50306-4:2003

SLOVENSKI STANDARD
SIST EN 50306-4:2003
01-februar-2003
Railway applications - Railway rolling stock cables having special fire performance
- Thin wall - Part 4: Multicore and multipair cables standard wall sheathed
Railway applications - Railway rolling stock cables having special fire performance - Thin
wall -- Part 4: Multicore and multipair cables standard wall sheathed
Bahnanwendungen - Kabel und Leitungen für Schienenfahrzeuge mit verbessertem
Verhalten im Brandfall - Reduzierte Isolierwanddicken -- Teil 4: Mehradrige und
mehrpaarige Leitungen mit Standardmantelwanddicken
Applications ferroviaires - Câbles pour matériel roulant ferroviaire ayant des
performances particulières de comportement au feu - Isolation mince -- Partie 4: Câbles
multiconducteurs et multipaires avec gaine d'épaisseur normale
Ta slovenski standard je istoveten z: EN 50306-4:2002
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
SIST EN 50306-4:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50306-4:2003

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SIST EN 50306-4:2003
EUROPEAN STANDARD EN 50306-4
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2002

ICS 13.220.40; 45.060.01


English version


Railway applications -
Railway rolling stock cables having special fire performance -
Thin wall
Part 4: Multicore and multipair cables standard wall sheathed


Applications ferroviaires -  Bahnanwendungen -
Câbles pour matériel roulant ferroviaire Kabel und Leitungen für
ayant des performances particulières Schienenfahrzeuge mit verbessertem
de comportement au feu - Verhalten im Brandfall -
Isolation mince Reduzierte Isolierwanddicken
Partie 4: Câbles multiconducteurs Teil 4: Mehradrige und mehrpaarige
et multipaires avec gaine d'épaisseur Leitungen mit Standardmantelwanddicken
normale




This European Standard was approved by CENELEC on 2002-06-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

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

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, 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


© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 50306-4:2002 E

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SIST EN 50306-4:2003
EN 50306-4:2002 - 2 -
Foreword

This European Standard was prepared by Working Group 12, Railway cables, of Technical
Committee CENELEC TC 20, Electric cables, as part of the overall programme of work in
CENELEC TC 9X, Electrical and electronic applications for railways.

The text of the draft was submitted to the Unique Acceptance Procedure and was approved
by CENELEC as EN 50306-4 on 2002-06-01.

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) 2003-07-01

- latest date by which the national standards conflicting
 with the EN have to be withdrawn (dow) 2008-07-01

Annexes designated “informative” are given for information only.
In this standard, annexes A and B are informative.
__________

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SIST EN 50306-4:2003
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Contents

Introduction. 4
1 Scope. 4
2 Normative references. 5
3 Multicore cables - sheathed . 6
4 Tests. 9
5 Multicore cables - screened and sheathed. 14
6 Tests. 17
7 Multipair cables - individually screened and sheathed and with an overall sheath. 22
8 Tests. 24
Annex A (informative) Guidance on selection of cables for type approval . 26
Annex B (informative) Bibliography . 26
Table 1 - Requirements for construction of multicore cables - sheathed . 8
Table 2 - Schedule of tests for multicore cables - sheathed . 13
Table 3 - Requirements for the construction of multicore cables - screened and sheathed . 16
Table 4 - Schedule of tests for multicore cables - screened and sheathed. 21
Table 5 - Requirements for the construction of multipair cables - individually screened
and sheathed and with an overall sheath . 24
Table 6 - Schedule of tests for multipair cables - individually screened and
sheathed and with an overall sheath . 25

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SIST EN 50306-4:2003
EN 50306-4:2002 - 4 -
Introduction

EN 50306 covers a range of sheathed and unsheathed cables with thin wall thickness
insulation, based on halogen free materials, for use in railway rolling stock. It is divided into
four parts:
Part 1: General requirements;
Part 2 : Single core cables;
Part 3: Single core and multicore cables (pairs, triples and quads) screened and thin wall
sheathed;
Part 4: Multicore and multipair cables, standard wall sheathed.

Special test methods referred to in EN 50306 are given in EN 50305. A Guide to Use is
1)
given in EN 50355 .

EN 50306-1, General requirements, contains a more extensive introduction to EN 50306,
and should be read in conjunction with this European Standard.
1 Scope

EN 50306-4 specifies requirements for, and constructions and dimensions of, multicore and
multipair cables rated 300 V to earth, of the following types:
- unscreened, sheathed for either exposed or protected wiring
2 2
(0,5 mm to 2,5 mm , number of cores from 2 to 48);
- screened, sheathed for either exposed or protected wiring
2 2
to 2,5 mm , number of cores from 2 to 8);
(0,5 mm
- screened, sheathed for either exposed or protected wiring
2 2
(0,5 mm to 1,5 mm , number of pairs of cores from 2 to 7).

NOTE 1  Not all conductor sizes/number of cores are specified for every type.

All cables have stranded tinned copper conductors, halogen-free, thin wall thickness
insulation and standard wall thickness sheath. Cable types are specified for use in exposed
situations (Class E), and for protected situations (Class P). They are for use in railway rolling
stock as fixed wiring, or wiring where limited flexing in operation is encountered. The
requirements provide for a continuous operational life at temperatures of 90 °C or 105 °C
dependent upon the sheath system type.

NOTE 2  In EN 50306-4 the higher temperature rating of 105 °C is only allowed where sheath type S2 is used,
and where it has been specifically tested for the higher rating (i.e. by long-term thermal endurance testing to
demonstrate a lifetime of at least 20 000 h at 125 °C).

The maximum temperature for short-circuit conditions of 160 °C is based on a duration of
5 s.

The cables specified in EN 50306-4 which have a sheath of type EM 101, EM 103 or S2
material are suitable for operation at temperatures as low as – 25 °C and those with sheath
of type EM 102 or EM 104 material are suitable for operation at temperatures as low as
- 40 °C.

NOTE 3  Where fuel oil is present sheath types EM 101 and EM 102 are not suitable.

NOTE 4  S2 material may also be suitable for operational temperatures as low as –40 °C, but if so must be
tested accordingly to confirm this.

1)
At draft stage.

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SIST EN 50306-4:2003
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Under fire conditions the cables exhibit special performance characteristics in respect of
maximum permissible flame propagation (flame spread) and maximum permissible emission
of smoke and toxic gases. These requirements are specified to permit the cables to satisfy
2)
Hazard Levels 2, 3 or 4 of EN 45545-1 .

NOTE 5  Requirements for the emission of smoke and gases are not specified for cables used for Hazard
Level 1 of EN 45545-1.

NOTE 6  EN 45545-1 is still under development and should be consulted.

EN 50306-4 should be used in conjunction with EN 50306-1, General requirements,
EN 50306-2, Single core cables, and EN 50306-3, Single core and multicore cables.
2 Normative references

This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and
the publications are listed hereafter. For dated references, subsequent amendments to or
revisions of any of these publications apply to this European Standard only when
incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies (including amendments).

2)
EN 45545-1 Railway applications - Fire protection of railway vehicles
Part 1: General
EN 50265-2-1 Common test methods for cables under fire conditions - Test for
resistance to vertical flame propagation for a single insulated
conductor or cable - Part 2-1: Procedures - 1 kW pre-mixed flame
EN 50267-2-1 Common test methods for cables under fire conditions - Tests on
gases evolved during combustion of materials from cables
Part 2-1: Procedures - Determination of the amount of halogen acid
gas
EN 50267-2-2 Common test methods for cables under fire conditions - Tests on
gases evolved during combustion of materials from cables
Part 2-2: Procedures - Determination of degree of acidity of gases for
materials by measuring pH and conductivity
EN 50268-2 Common test methods for cables under fire conditions - Measurement
of smoke density of cables burning under defined conditions
Part 2: Procedure
EN 50305 Railway applications - Railway rolling stock cables having special fire
performance - Test methods
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 60684-2 Flexible insulating sleeving - Part 2: Methods of test
EN 60811-1-1 Insulating and sheathing materials of electric and optical cables -
Common test methods - Part 1-1: General application - Measurement
of thickness and overall dimensions - Tests for determining the
mechanical properties (IEC 60811-1-1)

2)
At draft stage.

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SIST EN 50306-4:2003
EN 50306-4:2002 - 6 -
EN 60811-1-3 Insulating and sheathing materials of electric and optical cables -
Common test methods - Part 1-3: General application - Methods for
determining the density - Water absorption tests - Shrinkage test
(IEC 60811-1-3)
EN 60811-1-4 Insulating and sheathing materials of electric and optical cables -
Common test methods - Part 1-4: General application - Test at low
temperature (IEC 60811-1-4)
EN 60811-2-1 Insulating and sheathing materials of electric and optical cables -
Common test methods - Part 2-1: Methods specific to elastomeric
compounds - Ozone resistance, hot set and mineral oil immersion
tests (IEC 60811-2-1)
3 Multicore cables - sheathed
3.1 General

The completed cables shall conform to the applicable general requirements given in
EN 50306-1 and to the specific requirements of clause 3 and clause 4.

Conformity with the requirements shall be checked by inspection and by the tests given in
Table 2.
3.2 Designation, marking and coding
3.2.1 Code designation

For the purpose of supplying cables to this clause of the standard, the following code
designation shall be used:

- EN reference;
- table number;
- cable class (P or E);
- number of cores and conductor size;
- identifier for the particular Hazard Level (see 3.2.2);
- temperature rating.

For example:

EN 50306-4  1P  4x2,5  CC  90
3.2.2 Code identities for cables suitable for use in particular hazard levels

The following letters shall be used as a code to identify the suitability of a particular cable for
use under one of the Hazard Levels of EN 45545-1, and to indicate performance levels
relating to low temperature and to oil and fuel resistance:

NOTE  For sheathed cables two letters are required, one for the insulation and one for the sheath.

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SIST EN 50306-4:2003
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Hazard Level EN 45545-1 1 2 or 3 4

- low temperature / oil resistance A B C
- extra low temperature / oil resistance D E F
- low temperature / extra oil and fuel resistance G H J
- extra low temperature / extra oil and fuel resistance K L M
3.2.3 Marking on the insulation of cores

The cores shall be marked 1, 2, etc., in accordance with the requirements given in 3.3.2 of
EN 50306-2.

However, the core number one may be marked as the relevant single core in accordance
with the requirements of 3.3.1 of EN 50306-2.

3.2.4 Marking of the cable

The cables shall be marked with the following:

- manufacturer’s name;
- EN reference;
- table number ;
- cable class (P or E);
- voltage rating;
- number of cores and conductor size;
- identifier for the particular Hazard Level (see 3.2.2);
- temperature rating.

For example:

XYZ  EN 50306-4 1P  300 V  4x2,5  CC  90

The marking shall conform to the requirements of clause 5 of EN 50306-1.
3.3 Rated voltage

The rated voltage recognised for the purposes of this standard shall be 300 V to earth.

NOTE  See EN 50355 for further information.
3.4 Construction
3.4.1 Cores

Each insulated single core shall conform to the requirements given in EN 50306-2.
3.4.2 Laying-up of cores

The cores shall be twisted together.

The pitch of lay for the cores shall not be greater than 20 times the diameter of the laid up
cores in the cable.

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SIST EN 50306-4:2003
EN 50306-4:2002 - 8 -
3.4.3 Sheath

The sheath shall be either a compound of type S2, or a compound of type EM 101 to
EM 104, and shall be applied by extrusion. Compounds type EM 101 to EM 104 together
with their requirements are defined in EN 50264-1.

The sheath shall be smooth and uniformly applied; the application shall ensure that cables
with a class E sheath are substantially circular. The thickness of sheath shall conform to the
specified value given in Table 1 according to the class.

The sheath colour shall be black, unless otherwise specified.


Table 1 - Requirements for construction of multicore cables - sheathed

1 2 3 4 5 6 7
Number of Cables class E Cables class P
cores and Minimum Overall diameter Minimum Overall diameter
nominal thickness  thickness
cross-section of sheath  of sheath
of the
conductor min. max. min. max.
2
mm mm mm mm mm mm mm
4 x 0,5 1,0 5,5 6,5 0,42 4,1 5,1
7 x 0,5 1,0 6,3 7,3 0,42 4,9 5,9
13 x 0,5 1,0 8,3 9,3 0,56 7,3 8,3
19 x 0,5 1,0 9,0 10,2 0,56 8,1 9,1
37 x 0,5 1,0 12,3 13,5 0,56 10,8 12,0
4 x 0,75 1,0 6,0 7,0 0,42 4,6 5,6
7 x 0,75 1,0 6,9 7,9 0,42 5,5 6,5
13 x 0,75 1,0 9,1 10,3 0,56 8,2 9,2
19 x 0,75 1,0 10,0 11,2 0,56 9,0 10,2
37 x 0,75 1,0 13,2 14,4 0,56 12,2 13,4
48 x 0,75 1,0 14,8 16,4 0,56 13,9 15,5
4 x 1,0 1,0 6,3 7,3 0,42 4,9 5,9
7 x 1,0 1,0 7,3 8,3 0,42 6,0 7,0
13 x 1,0 1,0 9,7 10,9 0,56 8,7 9,9
19 x 1,0 1,0 10,7 11,9 0,56 9,8 11,0
37 x 1,0 1,0 14,0 15,6 0,56 13,3 14,5
4 x 1,5 1,0 7,4 8,4 0,42 6,0 7,0
7 x 1,5 1,0 8,6 9,8 0,56 7,7 8,7
13 x 1,5 1,0 11,7 12,9 0,56 10,7 11,9
19 x 1,5 1,0 13,0 14,2 0,56 12,0 13,2
37 x 1,5 1,0 17,2 18,8 0,56 16,2 17,8
2 x 2,5 1,0 7,7 8,7 0,56 6,7 7,7
3 x 2,5 1,0 8,1 9,1 0,56 7,7 8,1
4 x 2,5 1,0 8,8 10,0 0,56 7,9 8,9

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4 Tests
4.1 Definitions relating to tests

The definition of Type (T), Sample (S) and Routine (R) tests is as given in clause 3 of
EN 50306-1.

NOTE 1  Tests classified as Sample (S) or Routine (R) may be required as part of any approval schemes.

NOTE 2  Annex A gives guidance on the selection of cables for type approval.
4.2 Voltage test on cable

The test shall be carried out in accordance with 6.2.1 of EN 50305, using an a.c. or d.c.
voltage and the following conditions:

- sample length 20 m
- voltage (a.c.) 2 kV
- voltage (d.c.) 4,8 kV
- duration of application 5 min
- test temperature (20 ± 5) °C

At the conclusion of the test there shall be no breakdown of the insulation.
4.3 Long term ageing - Thermal endurance

NOTE  This test is only applicable to cables sheathed with S2 material rated at 105 °C.

The test shall be carried out in accordance with 7.3 of EN 50305.

The time to reach the end-point of the test shall be not less than 20 000 hours, when
determined by extrapolation to a temperature of 125 °C.
4.4 Hot set test on sheath

The test shall be carried out in accordance with clause 9 of EN 60811-2-1, using the
following conditions:

- temperature (200 ± 3) °C
- time under load 15 min
- mechanical stress 20 N/cm2

The maximum elongation shall be

100 % - under load,
25 %  - after unloading.

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SIST EN 50306-4:2003
EN 50306-4:2002 - 10 -
4.5 Mineral oil resistance of sheath

The test shall be carried out in accordance with clause 10 of EN 60811-2-1, using the
following conditions:

Treatment:
- type of fluid IRM 902
- temperature (100 ± 2) °C
- duration 24 h (72 h when using EM 103 or EM 104)

Requirement:
tensile strength variation ± 30 % maximum
elongation at break 100 % minimum
4.6 Fuel resistance of sheath

The test shall be carried out in accordance with clause 10 of EN 60811-2-1, using the
following conditions:

Treatment:
- type of fluid IRM 903
- temperature (70 ± 2) °C
- duration 168 h

Requirement:
tensile strength variation ± 30 % maximum
elongation at break 100 % minimum
4.7 Acid & alkali resistance of sheath

The test shall be carried out in accordance with clause 10 of EN 60811-2-1, using the
following conditions:

Treatment:
- type of acid bath N-oxalic acid solution
- type of alkali bath N-sodium hydroxide solution
- temperature (23 ± 2) °C
- duration 168 h

Requirement:
tensile strength variation ± 30 % maximum
elongation at break 100 % minimum

NOTE  Two separate tests are required; one in acid solution and one in alkali solution.

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4.8 Pressure at high temperature for S2 sheath

The test shall be carried out in accordance with 8.2 of EN 60811-3-1, using the following
conditions:

temperature (125 ± 2) °C
weight as test method
duration 4 h

At the conclusion of the test the indentation shall not exceed 50 %.
4.9 Tests at low temperature

a) Bending

The test shall be carried out at (- 40 ± 2) °C in accordance with 8.2 of EN 60811-1-4.

At the conclusion of the test there shall be no cracks in the sheath.

NOTE  Where cables with S2 sheaths are not to be used at extra low temperature, the test may be
carried out at (- 25 ± 2) °C.

b) Elongation

The test shall be carried out at (- 40 ± 2) °C in accordance with 8.4 of EN 60811-1-4.

The elongation of the sheath shall be not less than 30 %.

NOTE  Where cables with S2 sheaths are not to be used at extra low temperatures, the test may be
carried out at (- 25 ± 2) °C.

c) Impact

The test shall be carried out at (- 25 ± 2) °C in accordance with 5.1 of EN 50305.

At the conclusion of the test there shall be no cracks in the inside or the outside of the
sheath, nor on the outside of the insulation.
4.10 Ozone resistance of sheath

The test shall be carried out either in accordance with clause 8 of EN 60811-2-1 (for
Method A) or 7.4.2 of EN 50305 (for Method B), using the following conditions:

NOTE  The choice of Method A or Method B may be made by the supplier.

Method A:
-6
concentration (% by volume) (250 to 300) x 10
test temperature (25 ± 2) °C
test duration 24 h
test requirements no cracks

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SIST EN 50306-4:2003
EN 50306-4:2002 - 12 -
Method B:
-8
concentration (% by volume) (200 ± 50) x 10
test temperature (40 ± 2) °C
test duration 72 h
test requirements no cracks
4.11 Water absorption on sheath

The test shall be carried out in accordance with 9.2 of EN 60811-1-3, using samples
prepared as in 9.2.1(b) of that standard. The following test conditions apply:

- water temperature (70 ± 2) °C
- immersion duration 168 h

2
At the conclusion of the test the weight increase shall not exceed 15 mg/cm .

4.12 Compatibility

The test shall be carried out in accordance with 7.1 of EN 50305. Cable shall be aged for
7 days at the following temperatures:

(100 ± 2) °C for cables with a designated operating temperature of 90 °C;
(115 ± 2) °C for cables with a designated operating temperature of 105 °C.

Test requirement:
- tensile strength variation ± 30 % maximum
- elongation at break variation ± 30 % maximum
4.13 Reaction to fire

The completed cable shall conform to the requirements given in 8.1, 8.2.1, 8.2.2 or 8.2.3
(depending upon overall diameter) and 8.3 of EN 50306-1.

The sheath shall conform to the requirements of clause 9 of EN 50306-1.

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Table 2 - Schedule of tests for multicore cables - sheathed

1 2 3 4 5 6
Ref Test Category Test method given in Requirement
No of test EN (Sub)clause given in
a

1 Electrical tests
1.1 Electrical resistance of conductors T,S 50305 6.1 EN 50306-2, Table 1
1.2 Voltage test on complete cable T,S 50305 6.2.1 4.2

2 Provisions covering constructional
and dimensional characteristics
2.1 Checking of conformity and constructional T,S 50306-1 Inspection 3.4 & EN 50306-1, 6
provisions
2.2 Sheath:
(a) Application S 50306-1 Inspection & EN 50306-1, 6.6.2
  manual test
(b) Thickness T,S 50306-1 A.2 Table 1
2.3 Overall diameter T,S 50306-1 6.7 Table 1
2.4 Identification & marking T,S 50306-4 Inspection & 3.2.3 & 3.2.4
  measurement
2.5 Durability of identification T,S 50305 10.1 EN 50306-1, 5.3

3 Tests of sheath material
3.1 Mechanical properties of sheath in state T,S 60811-1-1 9.2 EN 50306-1, Table 1
as delivered  or
   EN 50264-1, Table 4
3.2 Long term ageing T 50305 7.3 4.3
3.3 Hot set test T,S 60811-2-1 9 4.4
3.4 Mineral oil immersion T 60811-2-1 10 4.5
3.5 Fuel resistance T 60811-2-1 10 4.6
3.6 Acid & alkali resistance T 60811-2-1 10 4.7
3.7 Pressure at high temperature T 60811-3-1 8.2 4.8
3.8 Tests at low temperature
 (a) Bending T 60811-1-4 8.2 4.9(a)
 (b) Elongation T 60811-1-4 8.4 4.9(b)
 (c) Impact resistance T 50305 5.1 4.9(c)
3.9 Ozone resistance T 50305 7.4.2 4.10
3.10 Water absorption (Gravimetric) T 60811-1-3 9.2 4.11
3.11 Compatibility test T 50305 7.1 4.12

4 Reaction to fire
4.1 Flame propagation
 (a) single cable T,S 50265-2-1 - 4.13 & EN 50306-1, 8.1
 (b) bunched cable (diameters ≥ 12 mm) T 50266-2-4 - 4.13 &
EN 50306-1, 8.2.1
 (c) bunched cable (diameters > 6 mm < 12 mm) T 50305 9.1.1 4.13 &
EN 50306-1, 8.2.2
 (d) bunched cable (diameters ≤ 6mm) T 50305 9.1.2 4.13 &
EN 50306-1, 8.2.3
4.2 Corrosive and acid gas emission of sheath, and T 50267-2-1 - 4.13 & EN 50306-1, 9
fluorine content 50267-2-2
60684-2
4.3 Smoke emission T 50268-2 - 4.13 & EN 50306-1, 8.3
4.4 Toxicity of sheath T 50305 9.2 4.13 & EN 50306-1, 9
a
According to EN 50306-4 unless otherwise specified.

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SIST EN 50306-4:2003
EN 50306-4:2002 - 14 -
5 Multicore cables - screened and sheathed
5.1 General

The completed cables shall conform to the applicable general requirements given in
EN 50306-1 and the specific requirements of clause 5 and clause 6.

Conformity with the requirements shall be checked by inspection and by the tests given in
Table 4.
5.2 Designation, marking and coding
5.2.1 Code designation

For the purpose of supplying cables to this clause of the standard, the following code
designation shall be used:

- EN reference;
- table number;
- cable class (P or E);
- number of cores and conductor size;
- identifier for the particular Hazard Level (see 3.2.2);
- temperature rating.

For example:

EN 50306-4 3P  8x0,75  CC  90
5.2.2 Marking on the insulation of cores

The cores shall be marked 1, 2, etc. in accordance with the requirements given in 3.3.2 of
EN 50306-2.

However, the core number one may be marked as the relevant single core in accordance
with the requirements of 3.3.1 of EN 50306-2.
5.2.3 Marking on the sheath of the cable

Cables shall be marked with the following:

- manufacturer’s name;
- EN reference;
- table number;
- cable class (P or E);
- voltage rating;
- number of cores and conductor size;
- identifier for the particular Hazard Level (see 3.2.2);
- screening;
- temperature rating.

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For example:

XYZ  EN 50306-4 3P 300 V  8x0,75  CC  S  90

The marking shall conform to the requirements of clause 5 of EN 50306-1.
5.3 Rated voltage

The rated voltage recognised for the purposes of this standard shall be 300 V to earth.

NOTE  Refer to EN 50355 for further information.
5.4 Construction
5.4.1 Cores

Each insulated single core shall conform to the requirements given in EN 50306-2.
5.4.2 Laying-up of cores

The cores shall be twisted together.

The pitch of lay for the cores shall not be greater than 20 times the diameter of the laid up
cores in the cable.

NOTE  An optional tape may be included at the manufacturer’s discretion.
5.4.3 Metallic braid screening

The braid shall consist of tinned, annealed copper wires. There shall be no more than one
splice in any spindle over any 100 mm length of the braid. The braid shall be applied evenly,
and it should neither slip nor leave an imprint in the insulation.

The filling factor Kr shall be according to the formula:
0,5
22
 
m.n.d πφ
Kr=× 1+
 
2
2πφ L
 
The wires of the braid shall be not less than 0,10 mm diameter. The filling factor Kr shall be
0,55 minimum.

The lay angle (the angle of a braid wire and the centreline of the cable) shall be between 15°
and 35°, and shall be checked by application of the following formula:
2 2
 π φ 
1,072 < 1+ ≤ 1,490
 
2
L
 
φ = diameter under the braid + 2d
d = nominal diameter of a wire
m = total number of spindles
n = number of wires per spindle
L = braiding pitch

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SIST EN 50306-4:2003
EN 50306-4:2002 - 16 -
5.4.4 Sheath

The sheath shall be either a compound of type S2, or a compound of type EM 101 to
EM 104, and shall be applied around the braid by extrusion. Compounds type EM 101 to
EM 104, together with their requirements, are defined in EN 50264-1.

The sheath shall be smooth and uniformly applied. The application shall ensure that cables
with a class E sheath are substantially circular. The thickness of sheath shall con
...