ISO/IEC TS 29125:2017/Amd 1:2020/Cor 1:2025

Overview

ISO/IEC TS 29125:2017/AMD 1:2020/Cor 1:2025 is a technical corrigendum to the ISO/IEC Technical Specification that sets telecommunications cabling requirements for the remote powering of terminal equipment. The corrigendum updates limits and an informative table used to assess temperature rise in 1‑pair cable bundles under remote powering conditions, clarifying that the calculations and table are based on 2 000 mA per conductor.

Key topics and requirements

• Updated current basis: The corrigendum replaces the prior reference of 1 000 mA with 2 000 mA per conductor as the basis for the temperature-rise table.
• Temperature‑rise table: A revised Table 7 shows temperature rise (°C) versus the number of 1‑pair cables in a bundle for several conductor diameters:
  • Conductor diameters included: 0.40 mm, 0.51 mm, 0.57 mm, 0.65 mm, 0.81 mm, 1.02 mm.
  • Installation conditions: Values provided separately for cables in air and in conduit.
  • Safety guidance: Temperature rises above 10 °C are highlighted as not recommended.
• Basis of values: The table’s values are derived from the implicit DC resistance of the listed conductor diameters. The corrigendum advises consulting manufacturers’ or suppliers’ specifications for cable‑specific data.
• Notation: A NOTE clarifies that the temperature rise figures assume 2 000 mA per conductor for all cables in the bundle.

Practical applications

• Assessing thermal performance of powered cabling bundles when delivering remote power to devices such as access points, cameras, IoT terminals and other powered equipment.
• Determining safe bundle sizes and conductor selections to avoid excessive temperature rise in installations (both in air and inside conduits).
• Informing design decisions for systems using remote powering over cabling (e.g., high-current Power over Ethernet variants or proprietary remote power solutions).

Who should use this standard

• Telecommunications and network cabling designers and engineers
• Installation contractors and site planners
• Facility managers and data center engineers
• Cable manufacturers and suppliers preparing technical specifications
• Standards writers and compliance officers evaluating remote power installations

Related standards

• ISO/IEC TS 29125:2017 (original Technical Specification)
• Amendment 1 (2020) and this Corrigendum (2025) as incorporated
• Complementary cabling standards (consult applicable national or international cabling standards for complete design and safety requirements)

This corrigendum is essential when specifying or validating cabling for remote powering scenarios; using the updated 2 000 mA basis and the revised Table 7 helps ensure thermal safety and reliable operation of powered terminal equipment.