Network Cable Chart

Cable is the part of a network you least want to replace, since pulling a new run through walls costs far more than the cable. A chart of the categories, speeds and distances helps you decide what to buy once and what to leave headroom for. The page has three tabs: copper categories, fibre speed and distance, and fibre types.

Copper categories at a glance

Cat 5 (100 MHz) was rated for 100BASE-TX and is obsolete. Cat 5e (100 MHz) supports 1000BASE-T at 1 Gbit/s over 100 m and has stricter crosstalk limits; 2.5GBASE-T and 5GBASE-T also run on it. Cat 6 (250 MHz) carries 1 Gbit/s over 100 m and 10 Gbit/s up to about 55 m. Cat 6A (500 MHz) carries 10GBASE-T over the full 100 m and is the usual choice for new 10 Gbit/s copper runs. Cat 7 (600 MHz) and Cat 7A (1000 MHz) are shielded S/FTP cables defined in ISO/IEC 11801, which TIA does not recognise, and often use non-RJ45 connectors. Cat 8 (2000 MHz) is shielded and meant for 25GBASE-T and 40GBASE-T links of up to 30 m between switches and servers.

The 100 m rule

Twisted-pair Ethernet links are limited to a channel of 100 m: normally up to 90 m of fixed cable in the wall plus patch cords at both ends. Longer runs need a switch, a media converter or fibre. The 55 m figure for 10 Gbit/s on Cat 6 is not a hard limit: it depends on how many cables are bundled together and how much electrical noise is nearby, and shorter distances may also fail in a noisy cable tray. The chart marks this in its notes.

Fibre tabs

The fibre speed and distance tab lists common fibre link standards with the fibre they need and the distance they reach, and the fibre types tab describes the multimode and single-mode types. Multimode is cheaper for short runs inside buildings, single-mode covers kilometres and tens of kilometres and is the default for anything between buildings. Optical loss over a run is calculated by the Fibre Loss Budget Calculator.

How to choose

Pick the cable by the speed you need over the distance you have, then add headroom for the next upgrade: wall cabling lasts decades while switches change every few years. For new office and home runs, Cat 6A is a safe default for copper, Cat 5e is acceptable where 1 Gbit/s will do, and single-mode fibre is the usual choice for backbones. Shielded cable only helps if it is terminated and grounded correctly.

A worked example

Suppose you need 10 Gbit/s to an access point 70 m from the cabinet. The chart shows that Cat 6 reaches only about 55 m at 10 Gbit/s, so it would be risky at 70 m, while Cat 6A is rated for 10GBASE-T over 100 m. A 25 Gbit/s link between two switches 20 m apart falls within Cat 8’s 30 m limit, though fibre or a direct-attach cable is the more common choice.

Limits

The figures are those of the standards, which assume good-quality components and workmanship; a poorly terminated cable can fail below its rating. The chart is a reference, not a test: certify installed links with a cable tester. Power over Ethernet adds a heating effect; see the PoE Power Calculator.

Related tools

• Fibre Loss Budget Calculator checks that an optical run fits its power budget.
• PoE Power Calculator plans the power on those copper runs.
• Server Rack Planner lays out the cabinets the cables run to.
• Link Budget Calculator covers links that replace cables with radio.