Ethernet Cable Categories: Cat5e vs Cat6 vs Cat6a
Basics4 minInnovialabs editorial team
In short
Cat5e reliably carries 1 Gbps over 100 m, Cat6 handles 10 Gbps only on short runs, and Cat6a delivers 10 Gbps over the full 100 m; for a new office, solid-copper Cat6a or at least Cat6 is the sensible choice.
The short answer
All three categories are twisted-pair cable with RJ45 connectors and a maximum run length of 100 metres. The difference is what speed the cable can sustain over that length:
| Category | Bandwidth | 1 Gbps | 2.5 and 5 Gbps | 10 Gbps |
|---|---|---|---|---|
| Cat5e | 100 MHz | up to 100 m | 2.5G usually up to 100 m | not designed for it |
| Cat6 | 250 MHz | up to 100 m | up to 100 m | short runs only, roughly up to 55 m |
| Cat6a | 500 MHz | up to 100 m | up to 100 m | up to 100 m |
If you're cabling a new office where the cable will sit in the walls for ten years or more, go with Cat6a, and use Cat6 as the minimum for desk runs on a tight budget. Cat5e is fine for small additions to an existing network, but there's no reason to design a new project around it.
Why speed matters already
Most office computers are fine with 1 Gbps. But cabling serves more than computers:
- Newer Wi-Fi access points have 2.5 Gbps ports and faster — gigabit cabling becomes the bottleneck;
- NAS and file servers benefit from 10 Gbps for large files, video and backups;
- links between switches and floors carry the whole office's traffic.
Re-cabling a finished office is expensive and slow. So choosing a category is a decision for the whole lease or building lifetime, not for today.
UTP or FTP: do you need shielding
The label tells you whether the cable is shielded:
- U/UTP — unshielded. The most common option for offices.
- F/UTP (often just called FTP) — an overall foil shield around all pairs.
- S/FTP — each pair in foil plus an overall braid.
Shielding helps when the cable runs next to power lines, motors, elevators or in industrial spaces. But a shielded system only works if it is shielded end to end: shielded jacks, patch panels, connectors and proper grounding. Shielded cable with ordinary connectors and no grounding gives you nothing and can even perform worse than UTP.
For a typical office, good-quality U/UTP Cat6a or Cat6 is enough.
Copper or CCA
CCA (copper-clad aluminium) is an aluminium conductor with a thin copper coating. It's cheaper, but:
- it does not meet category standards, even if the jacket says "Cat6";
- it has higher resistance, so signal quality suffers on long runs;
- it heats up more and wastes power with PoE;
- it breaks when bent and holds poorly in connectors.
How to tell: strip a conductor and scrape it — CCA shows silver aluminium under the thin copper layer. Ask the supplier to confirm solid copper (100% copper).
What to install in a new office
A project checklist:
- Category: Cat6a for access points, NAS, the server room and switch-to-switch links; Cat6a or Cat6 to desks.
- Solid copper, no CCA.
- All components in the same category: jacks, keystone modules, patch panels and patch cords. A link performs at the level of its weakest part.
- Spare ports: several outlets per workstation and dedicated ceiling runs for future access points and cameras.
- Length: permanent link up to 90 m, leaving 10 m for patch cords at both ends.
- Testing every link after installation and labelling outlets and ports.
Common mistakes
- Installing Cat6a cable with Cat5e jacks.
- Buying the cheapest cable without checking the conductor material.
- Using stranded patch cable for in-wall runs — it's meant for short cords.
- Tight bends and over-tightened cable ties, which degrade performance.