ISO/IEC TS 29125:2017/Amd 2:2024/Cor 1:2025

Information technology — Telecommunications cabling requirements for remote powering of terminal equipment — Amendment 2 — Technical Corrigendum 1

Technologies de l'information — Exigences de câblage des télécommunications pour téléalimentation d'équipement terminal — Amendement 2 — Rectificatif technique 1

General Information

• Status: Published
• Publication Date: 21-Dec-2025
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Drafting Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Current Stage: 6060 - International Standard published
• Start Date: 22-Dec-2025
• Completion Date: 22-Dec-2025

Relations

• Corrects: ISO/IEC TS 29125:2017/Amd 2:2024 - Information technology — Telecommunications cabling requirements for remote powering of terminal equipment — Amendment 2
• Effective Date: 27-Dec-2025

Overview

ISO/IEC TS 29125:2017/Amd 2:2024/Cor 1:2025 is an essential technical specification published by ISO for the information technology sector, focusing on telecommunications cabling requirements for remote powering of terminal equipment. This amendment and corrigendum update provides vital corrections and refinements to support safe and efficient remote powering, particularly addressing temperature rise in cabling systems under different installation and operational conditions. Adhering to these updated telecommunications cabling standards helps ensure safe deployment of remote power technologies such as Power over Ethernet (PoE) across diverse IT and telecom environments.

Key Topics

• Temperature Rise in Cables: The updated tables and figures provide revised data on temperature increases in different cable types and sizes, crucial when designing and installing remote powering systems.
  • Conduit vs. Air Installations: Separate data sets are presented for cables installed in air and in conduit, acknowledging their different heat dissipation characteristics.
  • Conductor Diameter and Bundle Size: The standard highlights how factors like conductor diameter (0.57 mm and 1.02 mm) and bundle size (from 7 to 91 cables) influence temperature rise.
  • Maximum Recommended Temperatures: Guidance is provided on when temperature thresholds (e.g., 10 K rise) should not be exceeded, ensuring cable performance and safety in environments possibly reaching 50°C.
• Corrections to Calculation Factors: The corrigendum clarifies and corrects previous calculation methods for certain cable installations, promoting accuracy in thermal management calculations.
• Deleted Paragraphs: Removal of statements about default assumptions (such as the ρ-factor for conductor tables), ensuring clarity and compliance with flexible real-world scenarios.

Applications

• Remote Powering of Equipment: Ensures reliable and safe powering of various terminal devices over structured cabling, such as IP cameras, wireless access points, industrial sensors, and networked building control systems.
• System Design and Engineering: Provides cable manufacturers, telecommunication engineers, and infrastructure designers with scientifically-backed tables and recommendations to assess temperature rise and select appropriate cabling options.
• Risk Management: Supports the identification and mitigation of potential overheating risks in cable bundles, helping organizations comply with both performance and health & safety requirements.
• Upgrading Existing Installations: Assists in evaluating existing telecommunication infrastructure for compatibility with higher power remote powering systems, ensuring compliance with latest international standards.

Related Standards

• ISO/IEC 11801 Series: General standards for generic cabling for customer premises, directly related to network infrastructure planning and installation.
• ISO/IEC 14763-2: Addresses planning and installation practices for information technology cabling, providing practical guidance complementing ISO/IEC TS 29125 requirements.
• IEEE 802.3 (Power over Ethernet): Defines PoE requirements, which rely on compliant structured cabling as specified by ISO/IEC TS 29125.
• ISO/IEC TS 60603-7: Standards for connectors used in cabling that is leveraged for remote powering applications.

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By following the updated guidelines and technical corrections presented in ISO/IEC TS 29125:2017/Amd 2:2024/Cor 1:2025, stakeholders in telecommunications can design and implement safer, more efficient, and fully compliant remotely powered systems for a wide range of IT applications.

Keywords: remote powering, telecommunications cabling, temperature rise, ISO/IEC TS 29125, structured cabling, Power over Ethernet, cable installation standards, IT infrastructure.

Standards Content (Sample)

ISO/IEC TS 29125:2017/AMD2:2024/COR1:2025 © ISO/IEC 2025
ISO/IEC TS 29125
Edition 1.0  2017-04
Information technology - Telecommunications cabling requirements
for remote powering of terminal equipment

AMENDMENT 2
CO RRI G E NDUM 1
6.4.4 Reducing temperature increase
Replace Table 9, Figure 4, Table 10, Figure 6, Table 11 and Figure 7 with the following new
Table 9, Figure 4, Table 10, Figure 6, Table 11 and Figure 7.

ISO/IEC TS 29125:2017-04/AMD2:2024-10/COR1:2025-12(en)

ISO/IEC TS 29125:2017/AMD2:2024/COR1:2025 © ISO/IEC 2025
Table 9 – Temperature rise for a 0,57 mm conductor diameter
1-pair cable versus current for different bundle sizes in conduit
Bundle Current
size
mA
200 400 600 800 1 000 1 200 1 400 1 600 1 800 2 000
∆T
K
7 0,2 0,6 1,4 2,4 3,8 5,4 7,4 9,6 12,2 15,0
19 0,3 1,0 2,3 4,1 6,4 9,3 12,5 16,3 20,7 25,5
37 0,4 1,5 3,3 5,9 9,2 13,2 18,0 23,5 29,7 36,7
61 0,5 1,9 4,4 7,8 12,1 17,5 23,8 31,0 39,3 48,5
91 0,6 2,4 5,5 9,8 15,2 22,0 29,9 39,0 49,4 61,0
Temperature rise above 10 K shown in grey background is not recommended for cables installed in an environment
that can reach 50 °C.
The values in this table are based on the DC resistance of the cable conductors. Manufacturers' and/or suppliers'
specifications give information relating to a specific cable.
NOTE The temperature rise for a particular cable is also dependent on the cable construction.

Figure 4 – Temperature rise for a 0,57 mm conductor diameter
1-pair cable versus current for different bundle sizes in conduit

ISO/IEC TS 29125:2017/AMD2:2024/COR1:2025 © ISO/IEC 2025
Table 10 – Temperature rise for a 1,02 mm conductor diameter
1-pair cable versus current for different bundle sizes in air
Bundle Current
size
mA
200 400 600 800 1 000 1 200 1 400 1 600 1 800 2 000
∆T
K
7 0,0 0,1 0,3 0,5 0,8 1,2 1,6 2,1 2,6 3,2
19 0,1 0,2 0,5 0,9 1,4 2,0 2,8 3,6 4,6 5,6
37 0,1 0,3 0,7 1,3 2,
...