Most offices need only two kinds of cable: Cat6 or Cat6A copper for desks and devices within 100 metres, and fibre for longer links between floors or buildings. Multimode fibre suits runs inside a building; single-mode suits runs between buildings.
Copper cables
Copper network cable (often called Ethernet or LAN cable) is what runs to desks, phones, printers, cameras and Wi-Fi access points. Each run can be up to 100 metres from the switch.
| Type | Top speed | Where it fits |
|---|---|---|
| Cat5e | 1 Gbps | Older installs. Fine to keep, not worth installing new. |
| Cat6 | 1 Gbps over 100 m; 10 Gbps up to about 37 m | Most desks, phones and cameras. |
| Cat6A | 10 Gbps over 100 m | Wi-Fi access points, switch links, new buildings. |
| Cat7 | 10 Gbps | Rare in offices. Shielded, ISO/IEC rather than TIA. |
| Cat8 | 25 to 40 Gbps up to about 30 m | Short links inside data centres. |
For a typical office the choice is really between Cat6 and Cat6A. Our Cat6 vs Cat6A guide goes into that.
Fibre cables
Fibre carries light instead of electricity. That means it can go much further than copper, and it is not affected by electrical noise. In offices it is used for the backbone: links between floors, between racks, or between buildings.
| Multimode (OM3 / OM4) | Single-mode (OS2) | |
|---|---|---|
| Core size | 50 µm | About 9 µm |
| 10 Gbps distance | About 300 m (OM3), 400 m (OM4) | Up to 10 km |
| Good for | Links between floors or inside a server room | Links between buildings or across a campus |
Copper or fibre?
- Copper (Cat6 or Cat6A): anything that plugs in at a desk, wall or ceiling, up to 100 metres from the switch.
- Multimode fibre: linking switches on different floors of the same building.
- Single-mode fibre: linking two buildings, or any run of several hundred metres or more.
Fibre is also the safer choice between buildings, because copper running outdoors between two structures can carry surges from lightning.
The cable is only part of it
Good cable installed badly still gives a bad network. What makes a cabling job last is clean termination, runs kept within limits, data cable kept away from power lines, and every link labelled and tested. That is the part to ask about when you compare quotes.
Last updated 4 November 2026