IEC 61156-8:2023

IEC 61156-8 ®
Edition 2.0 2023-02
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Multicore and symmetrical pair/quad cables for digital communications –
Part 8: Symmetrical pair/quad cables with transmission characteristics up to
1 200 MHz – Work area wiring – Sectional specification

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: sales@iec.ch.
IEC 61156-8 ®
Edition 2.0 2023-02
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Multicore and symmetrical pair/quad cables for digital communications –
Part 8: Symmetrical pair/quad cables with transmission characteristics up to
1 200 MHz – Work area wiring – Sectional specification
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.120.20 ISBN 978-2-8322-6488-1
– 2 – IEC 61156-8:2023 RLV © IEC 2023
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Installation consideration . 8
4.1 Installation conditions General remarks . 8
4.2 Bending radius of installed cable. 8
4.3 Climatic conditions . 8
5 Material and cable construction . 8
5.1 General remarks . 8
5.2 Cable construction . 8
5.2.1 General . 8
5.2.2 Conductor . 8
5.2.3 Insulation . 9
5.2.4 Cable element . 9
5.2.5 Cable make-up . 9
5.2.6 Screening of the cable core . 9
5.2.7 Sheath . 9
5.2.8 Identification . 10
5.2.9 Finished cable . 10
6 Characteristics and requirements . 10
6.1 General remarks . 10
6.2 Electrical characteristics and tests . 10
6.2.1 Conductor resistance . 10
6.2.2 Resistance unbalance within a pair . 11
6.2.3 Dielectric strength . 11
6.2.4 Insulation resistance . 11
6.2.5 Mutual capacitance . 11
6.2.6 Capacitance unbalance pair to ground . 11
6.2.7 Transfer impedance . 11
6.2.8 Coupling attenuation . 12
6.2.9 Current-carrying capacity . 12
6.2.10 Shield Resistance of the screen . 12
6.3 Transmission characteristics . 12
6.3.1 General remark . 12
6.3.2 Velocity of propagation (phase velocity) . 12
6.3.3 Phase delay and differential phase delay (delay skew) . 12
6.3.4 Attenuation (α) . 13
6.3.5 Unbalance attenuation near-end (TCL, EL TCTL). 14
6.3.6 Near-end crosstalk (PS NEXT, NEXT) . 15
6.3.7 Far-end crosstalk (FEXT) (PS ACR-F, ACR-F) . 15
6.3.8 Alien (exogenous) near-end crosstalk . 16
6.3.9 Alien (exogenous) far-end crosstalk . 16
6.3.10 Alien (exogenous) crosstalk of bundled cables . 16
6.3.11 Impedance . 16
6.3.12 Return loss (RL) . 17

6.4 Mechanical and dimensional characteristics and requirements . 17
6.4.1 Dimensional requirements . 17
6.4.2 Elongation at break of the conductors . 17
6.4.3 Tensile strength of the insulation . 17
6.4.4 Elongation at break of the insulation . 17
6.4.5 Adhesion of the insulation to the conductor . 17
6.4.6 Elongation at break of the sheath . 17
6.4.7 Tensile strength of the sheath . 18
6.4.8 Crush test of the cable . 18
6.4.9 Impact test of the cable . 18
6.4.10 Bending under tension . 18
6.4.11 Repeated bending of the cable . 18
6.4.12 Tensile performance of the cable . 18
6.4.13 Shock-test requirements of the cable . 18
6.4.14 Bump-test requirements of the cable . 18
6.4.15 Vibration-test requirements of the cable . 18
6.5 Environmental characteristics . 18
6.5.1 Shrinkage of insulation . 18
6.5.2 Wrapping test of insulation after thermal ageing . 18
6.5.3 Bending test of insulation at low temperature . 18
6.5.4 Elongation at break of the sheath after ageing . 19
6.5.5 Tensile strength of the sheath after ageing . 19
6.5.6 Sheath pressure test at high temperature . 19
6.5.7 Cold bend test of the cable . 19
6.5.8 Heat Hot shock test . 19
6.5.9 Damp heat steady state . 19
6.5.10 Solar radiation (UV) . 19
6.5.11 Solvent and contaminating fluids . 19
6.5.12 Salt mist and sulphur dioxide . 19
6.5.13 Water immersion . 19
6.5.14 Hygroscopicity . 19
6.5.15 Wicking. 19
6.5.16 Flame propagation characteristics of a single cable . 19
6.5.17 Flame propagation characteristics of bunched cables . 20
6.5.18 Resistance to fire . 20
6.5.19 Halogen gas evolution . 20
6.5.20 Smoke generation . 20
6.5.21 Toxic gas emission . 20
6.5.22 Integrated fire test . 20
7 Introduction to the blank detail specification . 20
Annex A (informative) Blank detail specification . 21
Bibliography . 27

Table 1 – Transfer impedance . 11
Table 2 – Coupling attenuation . 12
Table 3 – Attenuation, constant values . 13
Table 4 – Attenuation values . 14
Table 5 – Near-end crosstalk, power-sum (PS NEXT). 15

– 4 – IEC 61156-8:2023 RLV © IEC 2023
Table 6 – Far-end crosstalk (PS ACR-F) . 16
Table 7 – Return loss . 17

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MULTICORE AND SYMMETRICAL PAIR/QUAD CABLES
FOR DIGITAL COMMUNICATIONS –
Part 8: Symmetrical pair/quad cables with transmission
characteristics up to 1 200 MHz –
Work area wiring – Sectional specification

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 61156-8:2009+AMD1:2013 CSV. A vertical bar appears
in the margin wherever a change has been made. Additions are in green text, deletions
are in strikethrough red text.

– 6 – IEC 61156-8:2023 RLV © IEC 2023
IEC 61156-8 has been prepared by subcommittee 46C: Wires and symmetrical cables, of IEC
technical committee 46: Cables, wires, waveguides, RF connectors, RF and microwave passive
components and accessories. It is an International Standard.
This part of IEC 61156 is to be read in conjunction with IEC 61156-1:2023 and
IEC 61156-7:2023.
This second edition cancels and replaces the first edition published in 2009, and
Amendment 1:2013. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) align clauses with IEC 61156-1:2023;
b) additional reference to IEC 62153-4-9 test method (triaxial) for coupling attenuation
measurement to be consistent with all other parts of the IEC 61156 series;
c) incorporation of blank detail specification.
The text of this International Standard is based on the following documents:
Draft Report on voting
46C/1229/CDV 46C/1234/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 61156 series, published under the general title Multicore and
symmetrical pair/quad cables for digital communications, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

MULTICORE AND SYMMETRICAL PAIR/QUAD CABLES
FOR DIGITAL COMMUNICATIONS –
Part 8: Symmetrical pair/quad cables with transmission
characteristics up to 1 200 MHz –
Work area wiring – Sectional specification

1 Scope
This part of IEC 61156 relates to IEC 61156-1 and IEC 61156-7. The cables described herein
are specified up to 1 200 MHz and are specifically designed to build patch, equipment, and
work area cables as defined in ISO/IEC 11801 and ISO/IEC 15018 work area cords.
It covers a cable having four individually screened (STPS/FTP) pairs. The cable may can be
provided with a common screen over the cable core.
The transmission characteristics are specified for up to a frequency range 4 MHz to of
1 200 MHz and at a temperature of 20 °C.
These cables can be used for various communication channels which use as many as four pairs
simultaneously. In this sense, this sectional specification provides the cable characteristics
required by system developers to evaluate new systems.
The cables covered by this sectional specification are intended to operate with voltages and
currents normally encountered in communication systems and support the delivery of DC low
voltage remote powering applications. These cables are not intended to be used in conjunction
with low impedance sources, for example the electric power supply of public utility mains.
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.
IEC 60304, Standard colours for insulation for low-frequency cables and wires
IEC 61156-1:20072023, Multicore and symmetrical pair/quad cables for digital communications
– Part 1: Generic specification
IEC 62153-4-3, Metallic communication cable test methods – Part 4-3: Electromagnetic
compatibility (EMC) – Surface transfer impedance – Triaxial method
IEC 62153-4-5, Metallic communication cable test methods – Part 4-5: Electromagnetic
compatibility (EMC) –Screening or coupling attenuation − Absorbing clamp method
IEC 62153-4-9, Metallic communication cable test methods – Part 4-9: Electromagnetic
compatibility (EMC) – Coupling attenuation of screened balanced cables, triaxial method
IEC 61156-7, Multicore and symmetrical pair/quad cables for digital communications – Part 7:
Symmetrical pair cables with transmission characteristics up to 1 200 MHz – Sectional
specification for digital and analogue communication cables

– 8 – IEC 61156-8:2023 RLV © IEC 2023
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61156-1 apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
4 Installation consideration
4.1 Installation conditions General remarks
Installation considerations are defined in IEC 61156-1.
4.2 Bending radius of installed cable
The bending radius of the installed cable shall not be less than 4 times the outside diameter of
the cable.
4.3 Climatic conditions
Under static conditions, the cables shall operate in the temperature range from –20 °C to
+60 °C. The temperature dependence of the cables is specified for screened cables and should
be taken into account for the design of actual cabling systems.
The recommended temperature range during installation should be indicated in the relevant
detail specification.
When applications demand remote powering, the maximum temperature of the conductor shall
not exceed the maximum operating temperature of the cable. Dielectric performance can be
changed permanently due to over exposure of high temperatures.
5 Material and cable construction
5.1 General remarks
The choice of materials and cable construction shall be suitable for the intended application
and installation of the cable. Particular care shall should be taken to meet any special
requirements for fire performance (such as burning properties, smoke generation, evolution of
halogen gas, etc.) and remote powering.
5.2 Cable construction
5.2.1 General
The cable construction shall be in accordance with the materials, dimensions and assembly
details given in the relevant detail specification.
5.2.2 Conductor
The conductor shall be a solid or stranded annealed copper conductor, in accordance with
IEC 61156‑1, and shall should have a nominal diameter between 0,4 mm to and 0,65 mm. The
stranded conductor should have preferably seven strands. Higher conductor diameters may be
used if compatible with the connecting hardware.

5.2.3 Insulation
5.2.3.1 Insulation material
The conductor shall be insulated with a suitable thermoplastic material. Examples of suitable
materials are:
– polyolefin;
– fluoropolymer;
– low-smoke zero-halogen-free thermoplastic material.
The insulation may be solid or cellular with or without a solid dielectric skin. The insulation shall
be continuous and shall have a thickness such that the completed cable meets the specified
requirements. The nominal thickness of the insulation shall be compatible with the method of
conductor termination.
5.2.3.2 Colour code of insulation
The colour code is not specified but shall be indicated in the relevant detail specification. The
colours shall be readily identifiable and shall correspond reasonably with the standard colours
shown in IEC 60304.
NOTE It is acceptable to mark or stripe the "a" wire with the colour of the "b" wire to facilitate pair identification.
5.2.4 Cable element
5.2.4.1 Cable element type
The cable element shall be a screened twisted pair or quad adequately twisted.
5.2.4.2 Screening of the cable element
The screen for the cable element shall be in accordance with IEC 61156‑1. If a braid is used,
the minimum braid coverage shall be such as to meet the screening requirements of this
document. The individual components used to screen the cable element shall be in electrical
contact.
5.2.5 Cable make-up
A spacer may be used to separate the cable elements.
The cable elements, including spacers, shall be assembled to form the cable core.
The core of the cable may be wrapped with a protective layer of non-hygroscopic and not-
non‑wicking material.
5.2.6 Screening of the cable core
When required by the relevant detail specification, A screen for the cable core shall may be
provided. The screen shall be in accordance with IEC 61156‑1.
5.2.7 Sheath
The sheath material shall consist of a suitable thermoplastic material.
Examples of suitable materials are:
– polyolefin;
– PVC;
– 10 – IEC 61156-8:2023 RLV © IEC 2023
– fluoropolymer;
– low-smoke zero-halogen-free thermoplastic material.
The sheath shall be continuous, having a thickness as uniform as possible. A non-metallic
ripcord may be provided. When provided, the ripcord shall be non-hygroscopic and not-
non‑wicking.
The colour of the sheath is not specified but it shall should be stated specified in the relevant
detail specification.
5.2.8 Identification
5.2.8.1 Cable marking
Each length of cable shall be identified as to the manufacturer bear the name of the supplier
and the cable type and, when required provided, the year of manufacture, using one of the
following methods:
a) appropriately coloured threads or tapes;
b) with printed tape;
c) printing on the cable core wrapping;
d) marking on the sheath.
Additional markings, such as length marking, etc., are permitted. If used, such markings shall
refer to this should be indicated in the relevant detail specification.
5.2.8.2 Labelling
The following information shall be provided either on a label attached to each length of finished
cable or on the outside of the product package:
a) type of cable;
b) supplier’s name or logo;
c) year of manufacture;
d) length of cable in metres.
5.2.9 Finished cable
The finished cable shall be adequately protected for storage and shipment.
6 Characteristics and requirements
6.1 General remarks
Clause 6 lists the characteristics and minimum requirements of a cable complying with this
document. Test methods shall be in accordance with IEC 61156‑1:2023, Clause 6.
All the tests shall be carried out on a cable length of 100 m, unless otherwise specified.
6.2 Electrical characteristics and tests
The tests shall be carried out on a cable length of not less than 100 m, unless otherwise
specified.
6.2.1 Conductor resistance
The maximum conductor resistance shall not exceed 14,5 Ω/100 m of cable.

6.2.2 Resistance unbalance within a pair
6.2.2.1 Resistance unbalance within a pair
The resistance unbalance within a pair shall not exceed 1,5 2,0 %.
6.2.3 Dielectric strength
There shall be no failures when a test is The test shall be performed on conductor/conductor
and conductor/screen with 1,0 kV DC for 1 min or, alternately, with 2,5 kV DC for 2 s.
An AC voltage may be used. The AC voltage levels in these cases shall be 0,7 kV AC for 1 min
or, alternately, 1,7 kV AC for 2 s.
When installed in conjunction with power cables, local regulations can require a higher test
voltage
6.2.4 Insulation resistance
The test, immediately after the dielectric strength test, shall be performed on
– conductor/conductor;
– conductor/screen.
The minimum insulation resistance at 20 °C shall not be less than 5 000 MΩ∙km.
6.2.5 Mutual capacitance
The mutual capacitance is not specified but may be indicated in the relevant detail specification.
6.2.6 Capacitance unbalance pair to ground
The maximum capacitance unbalance pair to ground shall not exceed 1 200 pF/km at a
frequency of 1 kHz.
6.2.7 Transfer impedance
When measured using the triaxial method (IEC 62153-4-3), the transfer impedance shall not
exceed the values listed in Table 1 at the discrete indicated frequencies.
Table 1 – Transfer impedance
Maximum surface transfer
Frequency
impedance
MHz
mΩ/m
1 10
10 10
30 30
100 60
Frequency range Maximum surface transfer impedance
MHz mΩ/m
1 to 10 10
10 × f 10
10 to 100
– 12 – IEC 61156-8:2023 RLV © IEC 2023

NOTE Values in the range 10 MHz to 100 MHz are equal to IEC 61156-5, Grade 1.
6.2.8 Coupling attenuation
When measured using the absorbing clamp method (IEC 62153-4-5) or the triaxial method
(IEC 62153-4-9), the coupling attenuation in the frequency range from 30 MHz to 1 200 MHz
shall be equal to or greater than the values meet the requirements indicated in
Table 2.
Table 2 – Coupling attenuation
Frequency range Minimum coupling attenuation
MHz dB
30 to 100 ≥85,0
100 to 1 200 ≥ 85,0 - 20×log f 100
( )
NOTE Values in the range 30 MHz to 1 000 MHz are equal to IEC 61156-5, Type I.
6.2.9 Current-carrying capacity
The maximum current-carrying capacity is not specified but may be indicated in the relevant
detail specification. Further guidance with respect to current carrying capacity is provided by
ISO/IEC TS 29125 and the test method described in IEC 61156-1-4.
6.2.10 Shield Resistance of the screen
The maximum longitudinal DC resistance value of the individual screens or an overall screen
shall be less than 20 mΩ/m.
6.3 Transmission characteristics
6.3.1 General remark
All the tests shall be carried out on a cable length of 50 m, unless otherwise specified.
6.3.2 Velocity of propagation (phase velocity)
The requirement is not specified but may be indicated in the relevant detail specification.
6.3.3 Phase delay and differential phase delay (delay skew)
6.3.3.1 Phase delay
The phase delay, τ, shall be less than or equal to not exceed the value obtained from:

τ 500+ [ns / 100 m]
(1)
f
where
τ is the phase delay in ns/100 m;
f is the frequency in MHz.
6.3.3.2 Differential phase delay (delay skew)
Differential phase delay (delay skew) is the difference in phase delay between any two screened
cable elements.
When the phase delay is measured at (10 ± 2) °C 10 °C ± 3 °C and 40 °C ± 1 °C, the maximum
differential phase delay (delay skew between any two pairs) at a given temperature shall not be
greater than 25,0 ns/100 m in the frequency range from 4 MHz to 1 200 MHz.
6.3.3.3 Environmental effects
The differential delay (delay skew) between any two pairs due to temperature shall not vary by
more than ±10 ns/100 m over the temperature range from –20 °C to +60 °C while still meeting
the differential phase delay (delay skew) of 6.3.3.2.
6.3.4 Attenuation (α)
6.3.4.1 General figures Attenuation at 20 °C operating temperature
The maximum attenuation α of any pair in the frequency range indicated in Table 2 shall not
exceed 4 MHz to 1 200 MHz shall be less than, or equal to, the value obtained from Formula
(2) using the corresponding values of the constants given in Table 3.
c
α = a × f + b × f + (dB/100 m) (2)
f
C
α= A× f+×B f+ [dB / 100 m]
(2)
f
Table 3 – Attenuation, constant values
Constants
Frequency range
MHz
a B c
4 – 1 200 2,70 0,015 0,3
Constants
A B C
2,70 0,015 0,3
NOTE Cable performance between 1 MHz and 4 MHz is achieved by design only and it is therefore not necessary
to test for this performance below 4 MHz.
The values in Table 4 are for information only:
=
– 14 – IEC 61156-8:2023 RLV © IEC 2023
Table 4 – Attenuation values
Frequency Maximum attenuation at 20 °C
MHz dB/100 m
4 5,6
10 8,8
16 11,1
31,25 15,6
62,5 22,3
100 28,5
200 41,2
300 51,3
600 75,1
900 94,5
1 000 100,4
1 200 111,5
6.3.4.2 Attenuation at elevated operating temperature ambient temperatures
The increase in maximum attenuation requirement obtained from equation (2) due to elevated
temperature shall be 0,2 %/°C for screened cables.
6.3.5 Unbalance attenuation near-end (TCL, EL TCTL)
The minimum unbalance attenuation near-end (transverse conversion loss or TCL) shall be
equal to, or greater than, the value obtained from Formula (3) for all frequencies, f, in the
frequency range from 1 MHz to 200 250 MHz:
TCL = 40,0 -10×log ( f )  [dB] (3)
NOTE The need for TCL values above 200 MHz is under consideration.
NOTE 1 Values in the range 1 MHz to 30 MHz are equal to IEC 61156-5, Level 1.
TCL requirements for frequencies higher than 250 MHz may be defined in the detail
specification.
NOTE 2 If the intention is to increase the frequency range of balance measurements, IEC TR 61156-1-2 provides
guidance on the respective (e.g., balunless) measurement techniques.
The minimum equal-level far-end unbalance attenuation (equal-level transverse conversion
transfer loss or EL TCTL) shall be equal to, or greater than, the value obtained from Formula (4)
for all frequencies, f, in the range from 1 MHz to 30 MHz.
EL TCTL = 35,0 - 20×log f  [dB]
( ) (4)
NOTE 3 Values in the range 1 MHz to 30 MHz are equal to IEC 61156-5:2020, Level 1.
EL TCTL requirements for frequencies higher than 30 MHz may be defined in the detail
specification.
6.3.6 Near-end crosstalk (PS NEXT, NEXT)
The worst-pair power-sum near-end crosstalk, PS NEXT, of any pair for all frequencies in the
range 4 MHz to 1 200 MHz shall be equal to, or greater than, the value obtained from
Formula (5).
PS NEXT(f) = 103,0 – 15 × log (f)  (dB) (5)
PS NEXT = 103,0 -15×log f  [dB]
( ) (5)
where f is the frequency in MHz.
NOTE The cable performance between 1 MHz and 4 MHz is achieved by design only and it is therefore not
necessary to test for this performance below 4 MHz.
The values given in Table 5 are for information only. For those frequencies where the calculated
value of PS NEXT is greater than 75 dB, the requirement shall be 75 dB.
Table 5 – Near-end crosstalk, power-sum (PS NEXT)
Frequency Minimum PS NEXT
MHz dB
4 75
10 75
16 75
31,25 75
62,5 75
100 73
200 68
300 66
900 59
1 000 58
1 200 57
The minimum pair-to-pair NEXT for any pair combination shall be at least 3 dB better than the
PS NEXT for any pair.
6.3.7 Far-end crosstalk (FEXT) (PS ACR-F, ACR-F)
The worst-pair power-sum equal level far-end crosstalk, PS EL FEXT PS ACR-F, of any pair for
all frequencies in the range 4 MHz to 1 200 MHz shall be not less equal to, or greater than, the
value obtained from Formula (6).
PS EL FEXT(f) = 91,0 – 20 × log (f)  (dB for 100 m) (6)
PS ACR − F =91- 20×log f  [dB]
( ) (6)
where f is the frequency in MHz.

– 16 – IEC 61156-8:2023 RLV © IEC 2023
NOTE The cable performance between 1 MHz and 4 MHz is achieved by design only and it is therefore not
necessary to test for this performance below 4 MHz.
If FEXT loss is greater than 90 dB, calculation of PS ACR-F loss is not required.
The values given in Table 6 are for information only. For those frequencies where the calculated
value of PS EL FEXT PS ACR-F is greater than 75 dB, the requirement shall be 75 dB.
Table 6 – Far-end crosstalk (PS ACR-F)
Frequency Minimum PS ACR-F
MHz dB for 100 m
4 75
10 71
16 67
31,25 61
62,5 55
100 51
200 45
300 41
600 35
900 32
1 000 31
1 200 29
The minimum pair-to-pair EL FEXT ACR-F for any pair combination shall be at least 3 dB better
than the PS EL FEXT PS ACR-F for any pair.
6.3.8 Alien (exogenous) near-end crosstalk
Generally proven by design.
6.3.9 Alien (exogenous) far-end crosstalk
Generally proven by design.
6.3.10 Alien (exogenous) crosstalk of bundled cables
The minimum requirement is not specified but it should be stated in the relevant detail
specification.
Generally proven by design.
6.3.11 Impedance
The mean characteristic impedance shall be within ±5 % of the requested nominal impedance
at 100 MHz.
The impedance requirement is specified as fitted or mean characteristic impedance at a certain
frequency.
The impedance measured in accordance with IEC 61156-1 shall be 100 Ω ± 5 Ω at 100 MHz.

The return loss shall also be measured.
Further background on the measurement of fitted and mean characteristic impedance can be
found in IEC TR 61156-1-2. Recommendations given in IEC TR 61156-1-2 and
IEC TR 61156‑1‑5 for improvement of measurement uncertainty should be considered.
6.3.12 Return loss (RL)
The minimum return loss of any pair in the frequency 1 MHz to 1 200 MHz shall be equal to or
greater than the values obtained from Table 4 range indicated in Table 7 shall be greater than
the values in Table 7.
Table 7 – Return loss (RL)
Frequency range Minimum return loss
MHz dB
4 to10 20,0 + 5,0×log f
( )
10 to 20 25,0
20 to 250 25,0 - 8,6×log f 20
( )
250 to 600 15,6
15,6 -10×log f 600
600 to 1 200 ( )
6.4 Mechanical and dimensional characteristics and requirements
6.4.1 Dimensional requirements
The overall diameter of insulation, the nominal thickness of the sheath and the maximum overall
diameter of the sheath are not specified, but shall be indicated in the relevant detail
specification.
6.4.2 Elongation at break of the conductors
The minimum elongation at break of the conductor shall be not less than 8 %.
6.4.3 Tensile strength of the insulation
The tensile strength of the insulation is not specified, but may be specified indicated in the
relevant detail specification.
6.4.4 Elongation at break of the insulation
The minimum value of the elongation at break of the insulation shall be not less than 100 %.
6.4.5 Adhesion of the insulation to the conductor
The adhesion of the insulation to the conductor is not specified, but may be specified indicated
in the relevant detail specification.
6.4.6 Elongation at break of the sheath
The minimum value of the elongation at break of the sheath shall be not less than 100 %.

– 18 – IEC 61156-8:2023 RLV © IEC 2023
6.4.7 Tensile strength of the sheath
The minimum tensile strength of the sheath shall be not less than 9 MPa.
6.4.8 Crush test of the cable
The minimum force shall be 1 000 N.
6.4.9 Impact test of the cable
The impact resistance of the cable is not specified but shall may be indicated in the relevant
detail specification.
6.4.10 Bending under tension
The bending performance of the cable is not specified but shall be indicated in the relevant
detail specification.
6.4.11 Repeated bending of the cable
The cable shall withstand 500 cycles without cracking of the insulation or sheath or loss of
continuity of the metallic components.
6.4.12 Tensile performance of the cable
The tensile strength of the cable is not specified but may be indicated in the relevant detail
specification.
6.4.13 Shock-test requirements of the cable
Not applicable.
6.4.14 Bump-test requirements of the cable
Not applicable.
6.4.15 Vibration-test requirements of the cable
Not applicable.
6.5 Environmental characteristics
6.5.1 Shrinkage of insulation
When tested at (100 ± 2) °C for 1 h, the shrinkage of the insulation shall not exceed 5 %. The
length of the sample shall be 150 mm, and the shrink-back shall be measured as the sum from
both ends.
6.5.2 Wrapping test of insulation after thermal ageing
Not applicable.
6.5.3 Bending test of insulation at low temperature
The bending test of the insulated conductor shall be carried out at (−20 ± 2) °C. The mandrel
diameter shall be 6 mm. There shall be no cracks in the insulation.

6.5.4 Elongation at break of the sheath after ageing
The ageing regime shall be seven days at (100 ± 2) °C. The tensile strength elongation at break
after ageing shall not be less than 50 % of the unaged value.
6.5.5 Tensile strength of the sheath after ageing
The ageing regime shall be seven days at (100 ± 2) °C. The elongation tensile strength after
ageing shall be not less than 70 % of the unaged value.
6.5.6 Sheath pressure test at high temperature
Not applicable.
6.5.7 Cold bend test of the cable
The bending test shall be carried out at (−20 ± 2) °C. The mandrel diameter shall be eight times
the overall diameter of the cable. There shall be no cracks in the sheath.
6.5.8 Heat Hot shock test
Not applicable.
6.5.9 Damp heat steady state
Not applicable.
6.5.10 Solar radiation (UV)
The requirement resistance to solar radiation is not specified but may be specified in the
relevant detail specification.
6.5.11 Solvent and contaminating fluids
The requirement resistance to solvents and contaminating fluids is not specified but may be
specified in the relevant detail specification.
6.5.12 Salt mist and sulphur dioxide
Not applicable.
6.5.13 Water immersion
Not applicable.
6.5.14 Hygroscopicity
The amount of moisture gained after 3 h shall not exceed 1 % by in weight.
6.5.15 Wicking
The test solution shall not wet the filter paper at the end of 6 h.
6.5.16 Flame propagation characteristics of a single cable
When required If indicated in the relevant detail specifica
...