IEC 61156-3:2008

Overview

IEC 61156-3:2008 is the sectional specification for work area cables within the IEC 61156 series for multicore and symmetrical pair/quad cables for digital communications. It specifies construction, materials, electrical, transmission, mechanical and environmental requirements for cables intended for work area wiring as defined in ISO/IEC 11801. This third edition (2008) replaces the 2003 edition and introduces requirements for new Cat3 and Cat5 applications and revised numbering to align with the generic specification.

Key topics and requirements

The standard addresses the following technical areas and test parameters:

• Cable construction & materials

  • Screening options: individually screened elements, common overall core screen, or unscreened pairs/quads.
  • Conductors: annealed copper (solid or stranded), plain or tinned; nominal solid diameter 0.3–0.6 mm; stranded preferred as seven strands.
  • Insulation: suitable thermoplastics (examples: polyolefin, PVC, fluoropolymer, low‑smoke zero‑halogen).
  • Sheath, identification and finished cable construction requirements.

• Electrical characteristics

  • Conductor resistance and resistance unbalance
  • Dielectric strength and insulation resistance
  • Mutual capacitance and capacitance unbalance
  • Transfer impedance (for screened elements)

• Transmission performance

  • Velocity/phase propagation, attenuation, unbalance attenuation
  • Near‑end crosstalk (NEXT), power sum NEXT (PSNEXT) considerations
  • Characteristic impedance and Structural Return Loss (SRL)

• Mechanical & dimensional tests

  • Dimensional tolerances, elongation and tensile performance, crush, impact and repeated bending tests

• Environmental & safety

  • Thermal ageing, cold bend, heat shock, flame propagation, smoke generation and acid/toxic gas evolution; includes provisions for low‑smoke zero‑halogen performance where required.

• Operational limits

  • Recommended installation temperature range: 0 °C to +50 °C; normal operating range: −40 °C to +60 °C.
  • Cables are intended for communications voltages and currents and must not be connected to low‑impedance sources (e.g., public mains).

Applications and users

IEC 61156-3 is used to specify and verify work area cabling used in digital communications infrastructures. Typical users include:

• Cable manufacturers (product design and type testing)
• Network designers and system integrators (component selection and compliance)
• Cabling installers and contractors (installation and acceptance testing)
• Procurement and standards writers (specification and tendering)

This standard helps ensure interoperable, safe, and predictable performance of work area cables for LANs and other digital communication systems.

Related standards

• IEC 61156-1 (Generic specification) - IEC 61156-3 is intended to be read in conjunction with this part.
• ISO/IEC 11801 - Defines work area wiring and generic cabling topologies referenced by this document.
• Other referenced IEC documents (e.g., colour codes, conductor resistance calculation) are normative within the standard.

Keywords: IEC 61156-3, work area cable, Cat3, Cat5, multicore cable, screened pairs, unscreened quads, ISO/IEC 11801, NEXT, attenuation, LSZH.