IEC 61156-5:2020

Overview - IEC 61156-5:2020 (Horizontal floor wiring)

IEC 61156-5:2020 is the third edition sectional specification for multicore and symmetrical pair/quad cables intended primarily for horizontal floor wiring (as defined in ISO/IEC 11801). It specifies cable designs (individually screened, common screened and unscreened pairs or quads) with transmission characteristics up to 1 000 MHz, measured at 20 °C. The standard addresses cables used at the voltages and currents normally encountered in communication systems and explicitly supports low-voltage remote powering (e.g., Power over Ethernet - IEEE 802.3af/at/bt).

Key topics and technical requirements

IEC 61156-5 defines the practical and test requirements for horizontal cabling, including:

• Cable construction and materials: conductor, insulation, sheath, screening options and identification.
• Electrical characteristics and tests: conductor resistance, resistance unbalance, dielectric strength, insulation resistance, mutual capacitance and capacitance unbalance.
• Transmission performance up to 1 000 MHz: attenuation, velocity of propagation, delay skew, return loss and impedance.
• Crosstalk and alien crosstalk: NEXT, ACR‑F, ANEXT, AACR‑F and bundled-cable alien crosstalk criteria.
• Shielding and transfer impedance: requirements for screened constructions.
• Mechanical and environmental tests: bending radius, tensile/elongation, crush/impact, thermal ageing, damp heat, cold bend, UV, flame propagation and smoke/halogen considerations.
• Power delivery considerations: suitability for remote powering applications and reference to current measurement techniques and reports.
• Category references and blank detail specification: includes category 5e multipair guidance and an Annex A blank detail specification for product descriptions.

Practical applications

This standard is used to specify, manufacture, test and verify horizontal building cables for applications such as:

• Structured enterprise Ethernet cabling (horizontal distribution)
• Office and campus wiring supporting PoE devices (phones, APs, cameras)
• Telecommunications rooms and floor-level cabling trunks
• Environments requiring screened or unscreened pair/quad constructions up to 1 000 MHz

Who uses IEC 61156-5:2020

• Cable manufacturers and R&D teams creating pair/quad products
• Test laboratories and certification bodies performing electrical and environmental tests
• Network designers, integrators and installers specifying horizontal cabling
• Procurement/specification writers and standards committees

Related standards

• ISO/IEC 11801 (structured cabling and definition of horizontal wiring)
• IEEE 802.3af / 802.3at / 802.3bt (Power over Ethernet / remote powering)
• Other parts of the IEC 61156 series and referenced measurement technical reports

IEC 61156-5:2020 is essential when specifying high-performance balanced cables for modern horizontal networks requiring robust transmission to 1 000 MHz and reliable support for remote powering.