SIST-TS CLC ISO/IEC/TS 29125:2025/A2:2026

• Abstract:

  This document a) addresses the support of safety extra low voltage (SELV) and limited power source (LPS) applications that provide remote power over: - 4-pair balanced cabling in accordance with the reference implementations of EN 50173 series using currents per conductor of up to 500 mA; - 1-pair balanced cabling using currents per conductor of up to 2 000 mA; and targets the support of applications that provide remote power over balanced cabling to terminal equipment, b) covers the transmission and electrical parameters needed to support remote power over balanced cabling, c) covers various installation scenarios and how these may impact the capability of balanced cabling to support remote powering, d) specifies design and configuration of cabling as specified in EN 50173-1. NOTE SELV requirements specify a maximum voltage of 60 V DC and LPS is understood in the applications referenced to be up to 100 W supplied within cabling. This document includes a mathematical model to predict the behaviour of different bundle sizes, various cabling constructions, and installation conditions for different current capacities.

• Status: Published
• Publication Date: 08-Nov-2026
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: ELI - Electrical and communication installations
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 03-Nov-2026
• Due Date: 08-Jan-2027
• Completion Date: 09-Nov-2026
• Ref Project: CLC ISO/IEC/TS 29125:2025/A2:2026 - Information technology - Telecommunications cabling requirements for remote powering of terminal equipment

• Amends: SIST-TS CLC ISO/IEC/TS 29125:2025 - Information technology - Telecommunications cabling requirements for remote powering of terminal equipment (ISO/IEC/TS 29125:2017 + AMD1:2020)
• Effective Date: 01-Dec-2026

SLOVENSKI STANDARD
01-december-2026
Informacijska tehnologija - Zahteve za telekomunikacijske kable za daljinsko
napajanje opreme terminalov - Dopolnilo A2
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/TS 29125:2025/A2:2026
ICS:
35.200 Vmesniška in povezovalna Interface and interconnection
oprema equipment
SIST-TS CLC ISO/IEC/TS en
29125:2025/A2:2026
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION CLC ISO/IEC/TS 29125:2025/A2

SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION October 2026
ICS 35.200
English Version
Information technology - Telecommunications cabling
requirements for remote powering of terminal equipment
(ISO/IEC/TS 29125:2017/AMD2:2024)
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/AMD2:2024) (ISO/IEC/TS 29125:2017/AMD2:2024)
This Technical Specification was approved by CENELEC on 2026-10-12.

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
© 2026 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/A2:2026 E

European foreword
This document (CLC ISO/IEC/TS 29125:2025/A2:2026) consists of the text of document
ISO/IEC/TS 29125:2017/AMD2:2024, prepared by 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 Technical Specification ISO/IEC/TS 29125:2017/AMD2:2024 was approved
by CENELEC as a European Technical Specification without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60512-99-003 NOTE Approved as EN IEC 60512-99-003
IEC 61076-3-110 NOTE Approved as EN 61076-3-110
IEC 61076-3-104 NOTE Approved as EN 61076-3-104
IEC 61076-3-110 NOTE Approved as EN 61076-3-110

ISO/IEC TS 29125
Edition 1.0 2024-10
Corrected version
INTERNATIONAL
2025-12
STANDARD
AMENDMENT 2
Information technology – Telecommunications cabling requirements for remote

powering of terminal equipment

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 35.200 ISBN 978-2-8322-9893-0

– 2 – ISO/IEC TS 29125:2017/AMD2:2024
© ISO/IEC 2024
INFORMATION TECHNOLOGY –
TELECOMMUNICATIONS CABLING REQUIREMENTS
FOR REMOTE POWERING OF TERMINAL EQUIPMENT

AMENDMENT 2
FOREWORD
1) ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)
form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC
participate in the development of International Standards through technical committees established by the
respective organization to deal with particular fields of technical activity. ISO and IEC technical committees
collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental,
in liaison with ISO and IEC, also take part in the work.
2) The formal decisions or agreements of IEC and ISO 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 and ISO National bodies.
3) IEC and ISO documents have the form of recommendations for international use and are accepted by IEC and
ISO National bodies in that sense. While all reasonable efforts are made to ensure that the technical content of
IEC and ISO documents is accurate, IEC and ISO 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 and ISO National bodies undertake to apply IEC and ISO
documents transparently to the maximum extent possible in their national and regional publications. Any
divergence between any IEC and ISO document and the corresponding national or regional publication shall be
clearly indicated in the latter.
5) IEC and ISO do not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC and ISO marks of conformity. IEC and ISO are not
responsible for any services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this document.
7) No liability shall attach to IEC and ISO or their directors, employees, servants or agents including individual
experts and members of its technical committees and IEC and ISO National bodies 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 ISO/IEC document or any
other IEC and ISO documents.
8) Attention is drawn to the Normative references cited in this document. Use of the referenced publications is
indispensable for the correct application of this document.
9) IEC and ISO draw attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC and ISO take no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, IEC and ISO had not received notice of
(a) patent(s), which may be required to implement this document. However, implementers are cautioned that this
may not represent the latest information, which may be obtained from the patent database available at
https://patents.iec.ch and www.iso.org/patents. IEC and ISO shall not be held responsible for identifying any or
all such patent rights.
Amendment 2 to IEC ISO/IEC TS 29125:2017 has been prepared by subcommittee 25:
Interconnection of information technology equipment, of ISO/IEC joint technical committee 1:
Information technology.
The text of this Amendment is based on the following documents:
Draft Report on voting
JTC1-SC25/3272/DTS JTC1-SC25/3289/RVDTS

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 Amendment is English.

ISO/IEC TS 29125:2017/AMD2:2024 – 3 –
© ISO/IEC 2024
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1, and the ISO/IEC Directives, JTC 1 Supplement
available at www.iec.ch/members_experts/refdocs and www.iso.org/directives.
The content of the corrigendum 1 (2025-12) has been included in this copy.

___________
INTRODUCTION to the amendment
This amendment incorporates changes necessary to extend the current for remote powering
using single pair cabling up to 2 000 mA.
Introduction
Insert the following after the first bullet of the fourth paragraph:
• guidance on wire diameter and bundling on heating;
1 Scope
Replace the second bullet of list item a), added by Amendment 1, with:
• 1-pair balanced cabling using currents per conductor of up to 2 000 mA;
In the NOTE, delete "4-pair".
6.3 Temperature rise and current capacity
Replace the last sentence of the first paragraph with the following sentence:
The standards in the ISO/IEC°11801 series specify this temperature up to 60 °C in MICE C
environments and 70 °C in MICE C and C environments.
2 3
– 4 – ISO/IEC TS 29125:2017/AMD2:2024
© ISO/IEC 2024
Replace the existing Table 5, added by Amendment 1, with the following new Table 5:
Table 5 – Maximum current per conductor versus temperature rise
in a 37 1-pair cable bundle in air and conduit
Temperature
Current per conductor
rise
0,57 mm wire diameter 0,40 mm stranded wire 1,02 mm stranded wire
diameter (cords) diameter (cords)
K mA mA mA
air conduit air conduit air conduit
5 866 738 608 518 1 550 1 320
7,5 1 061 904 744 634 1 900 1 620
10 1 225 1 044 860 732 2 190 1 870
12,5 1 370 1 167 961 819 - 2 090
15 1 501 1 278 1 053 897 - -
17,5 1 621 1 381 1 137 969 - -
20 1 733 1 476 1 216 1 036 - -
Temperature rise above 10 K shown in grey background is not recommended for cables installed in an environment
that can reach 50 °C.
NOTE 1 These values are based on conductor temperature measurement of typical cables and cords.
NOTE 2 Currents above 2 000 mA are for information only.

In Table 6, added by Amendment 1, delete column "0,32 mm diameter", as follows:
Table 6 – Calculated worst case current per conductor versus temperature rise
in a bundle of 37 1-pair cables of different conductor diameters in air and conduit
0,40 mm 0,51 mm 0,57 mm 0,65 mm 0,81 mm 1,02 mm
diameter diameter diameter diameter diameter diameter

∆T mA mA mA mA mA mA
°C air conduit air conduit air conduit air conduit air conduit air conduit
2 384 327 490 417 548 466 624 532 779 663 981 835
4 543 463 693 590 775 660 883 753 1 101 938 1 387 1 181
6 666 567 849 723 949 808 1 082 922 1 349 1 149 1 699 1 446
8 769 655 981 835 1 096 933 1 249 1 065 1 558 1 327 1 962 1 670
10 860 732 1 096 934 1 225 1 044 1 397 1 190 1 742 1 484 2 194 1 867
12 942 802 1 201 1 023 1 342 1 143 1 530 1 304 1 908 1 625 2 403 2 046
14 1 017 867 1 297 1 105 1 450 1 235 1 653 1 409 2 061 1 755 2 596 2 210
16 1 087 926 1 387 1 181 1 550 1 320 1 767 1 506 2 203 1 877 2 775 2 362
18 1 153 983 1 471 1 253 1 644 1 400 1 874 1 597 2 337 1 991 2 943 2 506
20 1 216 1 036 1 551 1 321 1 733 1 476 1 976 1 684 2 463 2 098 3 102 2 641
Temperature rise above 10 °C shown in grey background is not recommended.
The values in this table are based on the implicit DC resistance derived from the insertion loss of the various
conductor diameters of cable. Manuf
...