IEC 61156-14:2025

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
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
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...