IEC 61156-2:2010

Overview

IEC 61156-2:2010 is the sectional specification for multicore symmetrical pair/quad cables intended for horizontal floor wiring in buildings. It covers individually screened or unscreened pair/quad constructions, with or without an overall screen, and defines transmission characteristics up to 100 MHz. This third edition (2010) supersedes the 2003 edition and explicitly includes Category 3 and Category 5 cable types. IEC 61156-2 is to be read together with IEC 61156-1:2002 (generic specification).

Key topics and technical requirements

• Cable types & construction
  • Individually screened or unscreened pair/quad cables; optional overall common screen.
  • Conductors: annealed copper, normally solid, nominal diameter 0.50–0.65 mm (up to 0.80 mm if compatible with connectors).
  • Insulation: suitable thermoplastic materials; color coding per IEC colour standards.
• Electrical characteristics
  • Conductor resistance and resistance unbalance.
  • Dielectric strength and insulation resistance.
  • Mutual capacitance, capacitance unbalance, and transfer impedance for screened elements.
• Transmission parameters (to 100 MHz)
  • Velocity of propagation (phase velocity), attenuation, NEXT (near-end crosstalk), FEXT (far-end crosstalk), characteristic impedance and structural return loss (SRL).
• Mechanical & dimensional tests
  • Dimensional tolerances, elongation and tensile strength of conductors/insulation/sheath, bending, crush and impact tests.
• Environmental & safety tests
  • Thermal ageing, low-temperature bending, flame propagation (single and bunched), smoke generation, acid/halogen gas evolution and combined air-handling space tests.
• Operational limits
  • Intended for communications voltages/currents only - not to be connected to low-impedance mains supplies.
  • Normal operating temperature range: –40 °C to +60 °C; installation recommended between –10 °C and +60 °C.

Applications

IEC 61156-2 is used for specifying and testing balanced pair/quad cables for:

• Horizontal building cabling in LANs and voice/data systems (structured cabling).
• Premises wiring where transmission performance up to 100 MHz is required.
• Environments requiring specific flame, smoke or halogen performance for safety and regulatory compliance.

Who uses this standard

• Cable manufacturers designing and certifying pair/quad products.
• Test laboratories performing electrical, mechanical and fire/smoke tests.
• System integrators, network designers and building specifiers writing procurement and installation requirements.
• Authorities and compliance teams ensuring cabling meets building and safety codes.

Related standards

• IEC 61156-1:2002 (Generic specification)
• IEC 61156-2-1 (Blank detail specification)
• IEC 60304 (Insulation colour codes)
• ISO/IEC 11801 (structured cabling definitions for horizontal wiring)

Keywords: IEC 61156-2, horizontal floor wiring, symmetrical pair cables, Category 3, Category 5, 100 MHz, structured cabling, cable specification, balanced pair/quad.