Overview
IEC TR 61156-1-6:2016 is a technical report published by the International Electrotechnical Commission (IEC). It provides informative nominal DC-resistance values for multicore and symmetrical pair/quad cables used in digital communications, specifically for floor-wiring and work-area installations. Understanding DC-resistance is essential for assessing cable performance, particularly for parameters influenced by resistance such as thermal heating in digital communication networks.
This technical report is intended for cable designers, system integrators, network planners, and professionals involved in the selection or evaluation of data cabling infrastructure. It contributes to performance analysis-especially important for applications where resistance directly impacts cable heating or power delivery, such as Power over Ethernet (PoE) and remote powering scenarios.
Key Topics
- Nominal DC-Resistance Values: The report details typical (informative) DC-resistance values for both horizontal floor wiring cables and work-area cables, categorized by cable type and category (e.g., Category 5e through Category 8.2).
- Cable Design Considerations: Highlights the dependency of DC-resistance on factors like conductor material, diameter, stranding, insulation, and shielding.
- Performance Impacts: DC-resistance influences cable attenuation and thermal heating. Cables with lower DC-resistance can manage higher performance and reduced temperature rise under load.
- Resistance Unbalance: The standard discusses resistance unbalance within and between cable pairs-a critical parameter for consistent data transmission and network stability.
- Guidance for Analysis: Provides values and calculation methods for resistance and resistance unbalance, aiding further technical analysis and informed decision-making regarding cabling systems.
Applications
IEC TR 61156-1-6:2016 is applicable in various settings where structured cabling systems are deployed, particularly:
- Office Networks and Buildings: For selecting floor-wiring and work-area cables to ensure compliance with thermal and performance requirements.
- Data Centers: Assisting network designers in choosing cables appropriate for high-density installations with considerable thermal load.
- Power over Ethernet (PoE): Vital for installations delivering power and data over the same cables, where excess resistance can limit power delivery or increase cable temperature.
- Remote Powering Applications: Any scenario where devices are powered remotely over data cables, making accurate knowledge of DC-resistance crucial for safety and reliability.
- Cable Manufacturing and Quality Control: Serves as a reference for manufacturing specifications, quality assessments, and R&D for improved cable designs.
Related Standards
The technical report references and complements several key IEC and ISO/IEC standards on digital communications cabling, including:
- IEC 61156-1: Generic specification for multicore and symmetrical pair/quad cables for digital communications.
- IEC 61156-5: Sectional specification for symmetrical pair/quad cables with transmission characteristics up to 1,000 MHz for horizontal floor wiring.
- IEC 61156-6: Sectional specification for work-area wiring cables.
- IEC 61156-9 & 61156-10: Specifications for cables supporting higher frequency channels (up to 2 GHz).
- ISO/IEC 11801: Information technology - Generic cabling for customer premises.
- ISO/IEC TR 29125: Cabling requirements for remote powering of terminal equipment.
Practical Value
Adopting the typical DC-resistance values and related guidance from IEC TR 61156-1-6:2016 helps stakeholders:
- Ensure the correct selection of data cables that support both high-speed communication and power delivery where needed.
- Analyze and predict thermal performance of cable installations, critical for network reliability and safety.
- Support the design and certification of structured cabling systems compliant with international standards.
By referring to the values and recommendations of IEC TR 61156-1-6:2016, organizations can optimize their digital communications infrastructure for both performance and efficiency.