Overview
IEC 62255-2:2005 is the sectional specification for unfilled multicore and symmetrical pair/quad outside-plant cables used in broadband digital communications (high bit-rate digital access telecommunication networks). It complements IEC 62255-1 (generic specification) and applies to unfilled cables typically manufactured in 6 to 300 pairs with a metallic screen over the core, a polyethylene jacket, copper conductors, and solid or cellular insulation. Cables are classified by maximum reference frequency (30 MHz, 60 MHz, or 100 MHz) and are intended for duct installation or aerial deployment (lashed or self-supporting).
Key Topics and Requirements
- Cable construction and materials
- Solid annealed copper conductors with diameters between 0.5 mm and 0.9 mm; factory joints allowed (joint breaking strength ≥ 90% of unjointed conductor).
- Insulation: polyolefin-based, either solid or cellular, with optional dielectric skin or multilayer systems.
- Core screening: single aluminium tape (plastic-coated on at least one side) or dual tape system (aluminium + steel armour); minimum metal tape thickness ≥ 0.15 mm.
- Sheath: polyethylene (LLDPE, MDPE or HDPE) with (2.5 ± 0.5)% carbon black; external sheath colour black. Inner PE jacket optional.
- Rip-cord: permitted and required to be non-hygroscopic/non-wicking.
- Strength members: galvanised steel support or glass/synthetic reinforcement for self-supporting aerial designs; Figure-8 messenger construction detailed in the spec.
- Performance domains
- Electrical, transmission, mechanical/dimensional, and environmental characteristics and test requirements are defined (see IEC 62255-1 for generic test methods).
- Not applicable
- Filling and flooding compounds are not applicable for unfilled cables under this part.
Applications and Who Uses It
- Telecommunications equipment manufacturers designing outside plant broadband cables for high-bit-rate access networks.
- Cable designers and OEMs specifying multicore pair/quad cables for duct, lashed aerial or self-supporting aerial deployments.
- Network engineers, procurement teams, and test laboratories validating compliance for cables operating up to 100 MHz reference frequency.
- Regulatory and standards compliance personnel referencing sectional and blank detail specifications for product acceptance.
Related Standards
- IEC 62255-1 - Generic specification (required reading).
- IEC 62255-2-1 - Blank detail specification for unfilled cables.
- IEC 60304, IEC 60708-1 - Colour codes and polyolefin sheath/insulation requirements referenced.
Keywords: IEC 62255-2:2005, unfilled cables, multicore cables, outside plant cables, broadband digital communications, polyethylene jacket, metallic screen, copper conductors, high bit rate access networks.