Cabling
Conduit Fill
The code limit on how much of a conduit's cross-section may be occupied by cable, set so cables can be pulled without damage and can dissipate heat.
Fill limits — commonly 40% for multiple conductors — exist for two reasons: an overfilled conduit damages jackets during the pull, and tightly packed PoE bundles run hot enough to degrade insertion loss. Both failures show up later as intermittent links, not as an obvious install fault.
Fill also has to be calculated for the building's future, not just today's count. Sizing pathways with spare capacity is a rounding error during construction and a wall-opening exercise afterwards.
Related terms
- Cat6 vs Cat6A
- Two copper cabling grades: Cat6 supports 10 Gbps to about 55 m, while Cat6A supports 10 Gbps to the full 100 m and resists alien crosstalk in dense bundles.
- PoE
- Delivery of DC power and data over the same Ethernet cable, so cameras, access points, phones, and displays need no local outlet.
- Structured Cabling
- A standards-based cabling system built as an organised hierarchy — entrance facility, backbone, telecom rooms, horizontal runs, work area outlets — rather than point-to-point runs added as needed.
- Firestopping
- Sealing cable penetrations through rated walls and floors with tested assemblies so the barrier's fire rating is restored.
More Cabling terms
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