IEC 61156-14:2025

Multicore and symmetrical pair/quad cables for digital communications - Part 14: Symmetrical single pair cables with transmission characteristics up to 20 MHz - Work area wiring - Sectional specification

IEC 61156-14:2025 specifies cables for work area wiring intended to be used for transmission of 10 Mb/s over a single twisted pair in channels for distances of up to 1 km. The transmission characteristics of these cables are specified up to a frequency of 20 MHz and at a temperature of 20°C. Depending on the MICE environment and the installation conditions, either unscreened or screened cables can be used. Furthermore, to consider different maximum transmission lengths, two sets of requirements are specified. The cable type A-1000W does not have attenuation de-rating compared to the A-1000 type according to IEC 61156-13 and is a design supporting up to 1 km channel length. The cable type A-400W has attenuation de-rating compared to the A-400 type according to IEC 61156-13. A blank detail specification can be found in Annex A.
The cables covered by this document are intended to operate with voltages and currents normally encountered in communication systems. While these cables are not intended to be used in conjunction with low impedance sources, for example the electric power supplies of public utility mains, they are intended to be used to support the delivery of DC low voltage remote powering applications.

General Information

• Status: Published
• Publication Date: 19-May-2025
• ICS: 33.120.20 - Wires and symmetrical cables
• Technical Committee: SC 46C - Wires and symmetric cables
• Drafting Committee: WG 7 - TC 46/SC 46C/WG 7
• Current Stage: PPUB - Publication issued
• Start Date: 20-May-2025
• Completion Date: 24-Jun-2025

Overview

IEC 61156-14:2025 is an international sectional specification for symmetrical single pair cables intended for work area wiring. It defines cables with transmission characteristics up to 20 MHz and is aimed at supporting 10 Mb/s over a single twisted pair in channel distances up to 1 km. Performance is specified at 20 °C and the document covers both unscreened and screened constructions depending on MICE environment and installation conditions. Two product classes are defined: A-1000W (designed to support up to 1 km without attenuation de-rating relative to IEC 61156-13 A-1000) and A-400W (which includes attenuation de-rating relative to IEC 61156-13 A-400). A blank detail specification is provided in Annex A.

Key topics and technical requirements

The standard specifies mechanical, electrical and environmental characteristics and associated tests, including:

• Electrical tests: conductor resistance, resistance unbalance, dielectric strength, insulation resistance, mutual capacitance and capacitance unbalance.
• Transmission parameters: attenuation (to 20 MHz), velocity of propagation/phase delay, impedance, return loss, and attenuation temperature coefficients.
• Crosstalk and coupling: transfer impedance, low-frequency coupling attenuation, unbalance attenuation (TCL and EL TCTL), and alien crosstalk metrics (PS ANEXT, PS AACR‑F).
• Mechanical and dimensional: conductor and insulation tensile/elongation, sheath properties, bending radius, crush/impact, repeated bending and tensile performance.
• Environmental: thermal ageing, cold bend, heat shock, damp heat, UV/solar radiation, solvent resistance, salt mist/sulphur dioxide, water immersion, flame propagation, halogen gas evolution, smoke and toxic gas tests.
• Powering considerations: cables are intended for voltages/currents typical in communications and to support DC low-voltage remote powering (not intended for public mains low‑impedance sources).

Applications

IEC 61156-14:2025 is targeted at work area wiring scenarios requiring long-reach single-pair links (up to 1 km) and predictable performance up to 20 MHz. Typical uses include:

• Long-distance single-pair data links in buildings and industrial facilities
• Work area cabling where low-frequency performance, immunity and environmental robustness are required
• Deployments that require optional screening depending on electromagnetic and mechanical conditions
• Systems that need DC low-voltage remote powering support (PoDL-like applications), not mains power

Who should use this standard

• Cable manufacturers and product designers specifying single-pair cables
• Test laboratories and compliance engineers verifying electrical/mechanical characteristics
• Network designers, systems integrators and specifiers for long-reach work area installations
• Procurement teams and certification bodies referencing a blank detail specification (Annex A)

Related standards

• IEC 61156-13 (reference for A-400 / A-1000 classes and attenuation comparisons)
• Annex A (blank detail specification) for product procurement and type approval

Keywords: IEC 61156-14, symmetrical single pair cables, work area wiring, 20 MHz, 1 km, A-1000W, A-400W, screened/unscreened, transmission characteristics, MICE environment, low-voltage remote powering.

Standards Content (Sample)

IEC 61156-14 ®
Edition 1.0 2025-05
INTERNATIONAL
STANDARD
Multicore and symmetrical pair/quad cables for digital communications –
Part 14: Symmetrical single pair cables with transmission characteristics up to
20 MHz – Work area wiring – Sectional specification
ICS 33.120.20  ISBN 978-2-8327-0451-6

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– 2 – IEC 61156-14:2025 © IEC 2025
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Installation considerations . 8
4.1 General remarks . 8
4.2 Bending radius of installed cable . 8
4.3 Climatic conditions . 8
5 Materials and cable construction . 8
5.1 General remarks . 8
5.2 Cable construction . 8
5.3 Conductor . 8
5.4 Insulation . 9
5.5 Cable element . 9
5.6 Screening of the cable element . 9
5.7 Cable make-up . 9
5.8 Screening of the cable core . 9
5.9 Sheath. 9
5.10 Identification . 9
5.11 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 . 10
6.2.3 Dielectric strength . 10
6.2.4 Insulation resistance . 10
6.2.5 Mutual capacitance . 10
6.2.6 Capacitance unbalance . 10
6.2.7 Transfer impedance . 11
6.2.8 Low frequency coupling attenuation . 11
6.2.9 Current-carrying capacity . 11
6.3 Transmission characteristics . 11
6.3.1 Velocity of propagation (phase velocity) . 11
6.3.2 Phase delay . 11
6.3.3 Attenuation (α) . 12
6.3.4 Unbalance attenuation (TCL and EL TCTL) . 13
6.3.5 Alien (exogenous) near-end crosstalk (PS ANEXT). 14
6.3.6 Alien (exogenous) far-end crosstalk (PS AACR-F) . 14
6.3.7 Impedance . 14
6.3.8 Return loss (RL) . 15
6.4 Mechanical and dimensional characteristics and requirements . 15
6.4.1 Dimensional requirements. 15
6.4.2 Elongation at break of the conductors . 15
6.4.3 Tensile strength of the insulation . 15
6.4.4 Elongation at break of the insulation . 15

6.4.5 Adhesion of the insulation to the conductor . 15
6.4.6 Elongation at break of the sheath . 15
6.4.7 Tensile strength of the sheath . 16
6.4.8 Crush test of the cable . 16
6.4.9 Impact test of the cable . 16
6.4.10 Bending under tension . 16
6.4.11 Repeated bending of the cable . 16
6.4.12 Tensile performance of the cable . 16
6.4.13 Shock test requirements of the cable . 16
6.4.14 Bump test requirements of the cable . 16
6.4.15 Vibration test requirements of a cable . 16
6.5 Environmental characteristics . 16
6.5.1 Shrinkage of insulation . 16
6.5.2 Wrapping test of insulation after thermal ageing . 16
6.5.3 Bending test of insulation at low temperature . 16
6.5.4 Elongation at break of the sheath after ageing . 17
6.5.5 Tensile strength of the sheath after ageing . 17
6.5.6 Sheath pressure test at high temperature . 17
6.5.7 Cold bend test of the cable . 17
6.5.8 Heat shock test . 17
6.5.9 Damp heat steady state . 17
6.5.10 Solar radiation (UV test) . 17
6.5.11 Solvents and contaminating fluids . 17
6.5.12 Salt mist and sulphur dioxide . 17
6.5.13 Water immersion . 17
6.5.14 Hygroscopicity . 17
6.5.15 Wicking . 17
6.5.16 Flame propagation characteristics of a single cable . 18
6.5.17 Flame propagation characteristics of bunched cables . 18
6.5.18 Halogen gas evolution . 18
6.5.19 Smoke generation . 18
6.5.20 Toxic gas emission. 18
6.5.21 Integrated fire test . 18
7 Bundled cables requirements . 18
8 Introduction to the blank detail specification (BDS) . 18

Annex A (informative) Blank detail specification . 19
Annex B (informative) Background information for coupling attenuation and low
frequency coupling attenuation requirements . 24
Bibliography . 25

Table 1 – Transfer impedance . 11
Table 2 – Low frequency coupling attenuation . 11
Table 3 – Attenuation equation constants . 12
Table 4 – Attenuation temperature coefficients . 12

– 4 – IEC 61156-14:2025 © IEC 2025
Table 5 – TCL requirements . 13
Table 6 – EL TCTL requirements. 14
Table 7 – PS ANEXT requirements . 14
Table 8 – PS AACR-F requirements . 14
Table 9 – RL requirements . 15

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MULTICORE AND SYMMETRICAL PAIR/QUAD CABLES
FOR DIGITAL COMMUNICATIONS –
Part 14: Symmetrical single pair cables with transmission characteristics
up to 20 MHz – Work area wiring – Sectional specification

FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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IEC 61156-14 has been prepared by subcommittee 46C: Wires and symmetric cables, of IEC
technical committee 46: Cables, wires, waveguides, RF connectors, RF and microwave passive
components and accessories. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
46C/1296/CDV 46C/1313/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
– 6 – IEC 61156-14:2025 © IEC 2025
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, or
• revised.
MULTICORE AND SYMMETRICAL PAIR/QUAD CABLES
FOR DIGITAL COMMUNICATIONS –
Part 14: Symmetrical single pair cables with transmission characteristics
up to 20 MHz – Work area wiring – Sectional specification

1 Scope
This part of IEC 61156 specifies cables for work area wiring intended to be used for
transmission of 10 Mb/s over a single twisted pair in channels for distances of up to 1 km. The
transmission characteristics of these cables are specified up to a frequency of 20 MHz and at
a temperature of 20 °C. Depending on the MICE environment and the installation conditions,
either unscreened or screened cables can be used. Furthermore, to consider different maximum
transmission lengths, two sets of requirements are specified. The cable type A-1000W does not
have attenuation de-rating compared to the A-1000 type according to IEC 61156-13 and is a
design supporting up to 1 km channel length. The cable type A-400W has attenuation de-rating
compared to the A-400 type according to IEC 61156-13. A blank detail specification can be
found in Annex A.
The cables covered by this document are intended to operate with voltages and currents
normally encountered in communication systems. While these cables are not intended to be
used in conjunction with low impedance sources, for example the electric power supplies of
public utility mains, they are intended to be used to support the delivery of DC low voltage
remote powering applications.
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 60708, Low-frequency cables with polyolefin insulation and moisture barrier polyolefin
sheath
IEC 61156-1, Multicore and symmetrical pair/quad cables for digital communications – Part 1:
Generic specification
IEC TS 61156-1-2, Multicore and symmetrical pair/quad cables for digital communications –
Part 1-2: Electrical transmission characteristics and test methods of symmetrical pair/quad
cables
IEC 61156-6, Multicore and symmetrical pair/quad cables for digital communications – Part 6:
Symmetrical pair/quad cables with transmission characteristics up to 1 000 MHz – Work area
wiring – Sectional specification
IEC 62153-4-3, Metallic communication cable test methods – Part 4-3: Electromagnetic
compatibility (EMC) – Surface transfer impedance – Triaxial method
IEC 62153-4-9:2018, Metallic communication cable test methods – Part 4‑9: Electromagnetic
compatibility (EMC) – Coupling attenuation of screened balanced cables, triaxial method
IEC 62153-4-9:2018/AMD1:2020/
IEC 62153-4-9:2018/AMD2:2024
– 8 – IEC 61156-14:2025 © IEC 2025
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 considerations
4.1 General remarks
Installation area considerations are defined in IEC 61156-1. Other areas may be considered.
4.2 Bending radius of installed cable
The maximum value of the minimum bending radius shall be four times the cable diameter
unless otherwise specified.
4.3 Climatic conditions
Under static conditions, the cable shall operate at least in the temperature range of the
environment from −20 °C to +60 °C.
The attenuation-increase due to the elevated operating temperature (temperature of the
environment) is described in 6.3.3.2.
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.
Extended temperature ranges are permitted but can cause safety issues. It may be specified in
the relevant detail specification.
5 Materials and cable construction
5.1 General remarks
For the purposes of this document, the respective requirements of IEC 61156-6 apply.
The choice of materials and cable construction shall be suitable for the intended application
and installation of the cable, and in line with the requirements of IEC 61156-1. Any additional
requirements for EMC and fire performance (such as burning properties, smoke generation,
volution of halogen gas) shall be met. Regional regulations can apply as well.
5.2 Cable construction
The cable construction shall be in accordance with the details and dimensions given in the
relevant detail specification.
5.3 Conductor
The conductor shall be a stranded or solid annealed copper conductor in accordance with
IEC 61156-1 and should have a nominal diameter between 0,4 mm and 1,3 mm.

5.4 Insulation
The conductor shall be insulated with a suitable material. Examples of suitable materials are:
– polyolefin,
– fluoropolymer, and
– low-smoke halogen-free thermoplastic material.
The colour code shall be in accordance with IEC 60708 if not specified differently in the
respective detail specification.
5.5 Cable element
The cable element shall be a balanced pair and shall be twisted. A third insulated wire may be
twisted together with the pair for earthing and grounding purpose.
5.6 Screening of the cable element
If screened, the screen of the cable element shall be in accordance with IEC 61156-1.
5.7 Cable make-up
Bedding material may be used in the cable element to separate the cable element from other
design elements (e.g. braid, armouring). The cable element and its screen may be covered by
an intermediate jacket. This jacket shall be in accordance with 5.9. The core of the cable may
be wrapped with a protective layer of non-hygroscopic and non-wicking material.
5.8 Screening of the cable core
If screened, the screen of the cable core shall be in accordance with IEC 61156-1.
5.9 Sheath
The sheath material shall consist of a suitable material. Examples of suitable materials are
– polyolefin,
– PVC,
– fluoropolymer, and
– low-smoke 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 non-wicking.
The colour of the sheath is not specified but it should be specified in the relevant detail
specification.
5.10 Identification
Each length of cable shall be identified as to the supplier and, when required, a traceability
code, using one of the following methods:
– appropriately coloured threads or tapes;
– with a printed tape;
– printing on the cable core wrapping;
– marking on the sheath.
Additional markings, such as length marking, are permitted. If used, such markings shall refer
to this document.
– 10 – IEC 61156-14:2025 © IEC 2025
5.11 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, except for the length of the
cable under test which shall be as specified in 6.1. If balunless testing is used, it should be in
accordance with IEC TS 61156-1-2.
The computed requirements in dB, rounded to one decimal place, shall be used to determine
compliance.
The tests for electrical characteristics in accordance with 6.2 shall be carried out on a cable
length of not less than 100 m, unless otherwise specified.
The tests for transmission characteristics in accordance with 6.3 shall be carried out on a cable
length of 100 m, unless otherwise specified.
6.2 Electrical characteristics and tests
6.2.1 Conductor resistance
The maximum conductor resistance at or corrected to 20 °C shall not exceed 23 Ω/km for cable
type A-1000W or 108,75 Ω/km for cable type A-400W.
6.2.2 Resistance unbalance within a pair
The resistance unbalance shall not exceed 2,0 %.
6.2.3 Dielectric strength
There shall be no failures when a test is performed on conductor/conductor and, where
screen(s) are present, a conductor/screen with 1,0 kV DC for 1 min or, alternatively, 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 alternatively 1,7 kV AC for 2 s.
6.2.4 Insulation resistance
The test, immediately after the dielectric strength test, shall be performed on
– conductor/conductor, and
– conductor/screen if screen(s) are present.
The minimum insulation resistance at 20 °C shall be not less than 5 GΩ·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
The maximum capacitance unbalance pair to ground shall not exceed 1 600 pF/km at a
frequency of 800 Hz or 1 000 Hz.

IEC 61156
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