How to Select the Right Telecom Cable

Size the pair count for the design horizon

Specify the pair count against the projected demand at the end of the asset's life, not today's connection list. Re-entering a duct to add capacity typically costs several times the original cable spend.

A common rule for distribution routes is to design for current demand plus 50% growth, then round up to the next standard pair count so you stay on a stocked construction.

Filled, air-core or gel-block

Fully filled (jelly-filled) cables resist longitudinal water migration and are the default for direct-buried and duct routes that may flood. Air-core constructions are lighter and easier to terminate, and suit dry internal or pressurised networks.

Where a route mixes conditions, gel-blocked designs give water blocking at the core without the mess of a fully filled cable through the building entry.

Barrier and armour

An aluminium/polyethylene laminate barrier handles most duct and internal routes. Steel tape adds crush resistance for direct burial, and steel wire armour is the choice where rodent attack or mechanical damage is a genuine risk.

• Duct, dry: air-core, AL/PE barrier
• Duct, flood risk: filled core, AL/PE barrier
• Direct buried: filled core, steel tape armour
• Rodent or high mechanical risk: steel wire armour