SIST-TS CLC ISO/IEC/TS 29125:2025

SLOVENSKI STANDARD
01-junij-2025
Informacijska tehnologija - Zahteve za telekomunikacijske kable za daljinsko
napajanje opreme terminalov (ISO/IEC/TS 29125:2017 + AMD1:2020)
Information technology - Telecommunications cabling requirements for remote powering
of terminal equipment (ISO/IEC/TS 29125:2017 + AMD1:2020)
Informationstechnik - Anforderungen an die die Teleommunikationsverkabelung zur
Fernspeisung von Endgeräten (ISO/IEC/TS 29125:2017 + AMD1:2020)
Technologies de l'information - Exigences de câblage des télécommunications pour
téléalimentation d'équipement termina (ISO/IEC/TS 29125:2017 + AMD1:2020)
Ta slovenski standard je istoveten z: CLC ISO/IEC/TS 29125:2025
ICS:
35.200 Vmesniška in povezovalna Interface and interconnection
oprema equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION CLC ISO/IEC/TS 29125

SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION April 2025
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 Technical Specification was approved by CENELEC on 2025-04-21.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to make the TS available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force.

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.

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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC ISO/IEC/TS 29125:2025 E

European foreword
This document (CLC ISO/IEC/TS 29125:2025) 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”.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard ISO/IEC/TS 29125:2017 and ISO/IEC/TS
29125:2017/AMD1:2020 was approved by CENELEC as a European Standard without any
modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60512-2-1:2002 NOTE Approved as EN 60512-2-1:2002 (not modified)
IEC 60603-7 series NOTE Approved as EN 60603-7 series
IEC 61076-3-104 NOTE Approved as EN 61076-3-104
IEC 61076-3-110 NOTE Approved as EN 61076-3-110
IEC 60512-99-002 NOTE Approved as EN IEC 60512-99-002
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
This standard has been withdrawn.
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 .
...