CLC ISO/IEC/FprTS 29125:2024

SLOVENSKI STANDARD
01-februar-2025
Informacijska tehnologija - Zahteve za telekomunikacijske kable za daljinsko
napajanje opreme terminalov
Information technology - Telecommunications cabling requirements for remote powering
of terminal equipment
Informationstechnik - Anforderungen an die die Teleommunikationsverkabelung zur
Fernspeisung von Endgeräten
Technologies de l'information - Exigences de câblage des télécommunications pour
téléalimentation d'équipement terminal
Ta slovenski standard je istoveten z: CLC ISO/IEC/FprTS 29125:2024
ICS:
35.200 Vmesniška in povezovalna Interface and interconnection
oprema equipment
kSIST-TS CLC ISO/IEC/FprTS en
29125:2025
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION FINAL DRAFT
CLC ISO/IEC/FprTS 29125
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
December 2024
ICS 35.200 -
English Version
Information technology - Telecommunications cabling
requirements for remote powering of terminal equipment
(ISO/IEC/TS 29125:2017 + AMD1:2020)
Technologies de l'information - Exigences de câblage des Informationstechnik - Anforderungen an die die
télécommunications pour téléalimentation d'équipement Teleommunikationsverkabelung zur Fernspeisung von
terminal Endgeräten
(ISO/IEC/TS 29125:2017 + AMD1:2020) (ISO/IEC/TS 29125:2017 + AMD1:2020)
This draft Technical Specification is submitted to CENELEC members for vote by correspondence.
Deadline for CENELEC: 2025-03-14.

The text of this draft consists of the text of ISO/IEC/TS 29125:2017 + AMD1:2020.

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

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a Technical Specification. It is distributed for review and comments. It is subject to change without notice
and shall not be referred to a Technical Specification.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Project: 80514 Ref. No. CLC ISO/IEC/FprTS 29125:2024 E

European foreword
This document (CLC ISO/IEC/FprTS 29125:2024) consists of the text of ISO/IEC/TS 29125:2017 and
ISO/IEC/TS 29125:2017/AMD1:2020, prepared by ISO/IEC JTC 1/SC 25 “Interconnection of
information technology equipment” of ISO/IEC JTC 1 “Information technology”.
This document is currently submitted to voting in accordance with the Internal Regulations, Part 2,
Subclause 11.3.3 for acceptance as a CENELEC Technical Specification.
The following date is proposed:
• latest date by which the existence of (doa) dav + 6 months
this document has to be announced at
national level
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
ISO/IEC 11801-1 - Information technology – Generic cabling - -
for customer premises – Part 1: General
requirements
ISO/IEC 14763-2 - Information technology – Implementation - -
and operation of customer premises -
cabling – Part 2: Planning and installation
ISO/IEC TR 24746 - Information technology – Generic cabling - -
for customer premises – Midspan DTE
power insertion
ISO/IEC TS 29125
Edition 2.0 2017-04
TECHNICAL
SPECIFICATION
colour
inside
Information technology – Telecommunications cabling requirements for remote

powering of terminal equipment

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 35.200 ISBN 978-2-8322-4223-0

– 2 –  ISO/IEC TS 29125:2017 © ISO/IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 8
4 Conformance . 8
5 Cabling selection and performance . 9
6 Installation conditions . 9
6.1 General . 9
6.2 Ambient temperature. 9
6.3 Temperature rise and current capacity . 9
6.4 Factors affecting temperature increase . 11
6.4.1 General . 11
6.4.2 Installation near equipment . 11
6.4.3 Cable count within a bundle . 11
6.4.4 Reducing temperature increase . 12
6.4.5 Cable bundle suspended in air . 13
6.4.6 Administration. 14
7 Remote power delivery over balanced cabling . 14
8 Connecting hardware . 15
Annex A (informative) Mitigation considerations for installed cabling . 17
A.1 General . 17
A.2 Minimum cabling class . 17
A.3 Bundle size and location . 17
A.4 Mitigation options . 17
Annex B (informative) Modelling temperature rise for cable types, bundle sizes and
installation conditions . 18
B.1 Model basics . 18
B.2 Power dissipated (P) . 18
B.3 Temperature difference from ambient temperature to bundle surface (∆T ) . 19
u
B.3.1 Model equations . 19
B.3.2 Typical values for constant ρ . 19
u
B.4 Temperature difference from bundle surface to bundle centre (∆T ) . 19
th
B.4.1 Model equations . 19
B.4.2 Typical values for constant ρ . 19
th
B.5 Temperature variation within the bundle (∆T(x)) . 20
B.6 Alternative presentation of the model . 20
B.7 Adaptation model used to derive temperature rise vs. cables in a bundle . 20
B.8 Calculations . 21
B.9 Example. 21
B.10 Coefficients for air and conduit. 22
Annex C (informative) Transmission parameters related to remote powering. 23
C.1 DC loop resistance. 23

ISO/IEC TS 29125:2017 © ISO/IEC 2017 – 3 –
C.2 DC resistance unbalance (within pair) . 23
C.3 DC resistance unbalance (pair to pair) . 24
Annex D (informative) Illustrations of heating of various bundle sizes and
configurations . 26
D.1 Limiting cable bundle size . 26
D.2 Separating into smaller bundles . 27
Annex E (informative) Test protocol . 28
E.1 Background. 28
E.2 Test set-up . 28
Annex F (informative) Detailed test procedure . 30
F.1 General . 30
F.2 Test set-up . 30
F.2.1 Thermocouple placement . 30
F.2.2 Measurement of cable bundle in air . 31
F.2.3 Measurement of cable bundle in conduit . 32
Bibliography . 34

Figure 1 – Examples of end point powering systems using signal pairs (top) and spare
pairs (bottom) . 14
Figure 2 – Examples of mid-span powering systems . 15
Figure B.1 – Temperature rise profile . 18
Figure D.1 – 91-cable bundle . 26
Figure D.2 – Three bundles of 37 cables . 26
Figure D.3 – Three bundles of 37 cables with separation . 27
Figure E.1 – 37-cable bundle and temperature location. 28
Figure E.2 – "Perfect bundle" and thermocouple configuration . 29
Figure E.3 – Conductor configuration . 29
Figure F.1 – Placement of thermocouple . 30
Figure F.2 – Securing of the thermocouple. 31
Figure F.3 – Test set-up for cable bundles in air . 32
Figure F.4 – Test set-up for cable bundles in conduit . 33
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