Specs from ANSI/TIA-568 & IEEE 802.3 · reviewed · the full Ethernet guide
The category printed on the box is a promise about speed, distance, and interference. Pick the one your run actually needs — under-spec and it will not certify; over-spec and you have paid for headroom you will never use. Answer four questions and this points to the right grade.
Recommended
Cat6a
10 Gigabit — Cat6a is the reliable 10G-to-100 m spec.
- A clean office run can use UTP Cat6a, but it is bulkier — foil (F/UTP) is the safe default.
- Bare copper only — copper-clad aluminum (CCA) will not certify and is a PoE and fire-code risk.
- Match the jacket fire rating to the space: CM (general), CMR (riser), or CMP (plenum), per the NEC.
The categories at a glance
| Category | Max speed & reach | Bandwidth | Typical shielding |
|---|---|---|---|
| Cat5e | 1 GbE to 100 m | 100 MHz | U/UTP |
| Cat6 | 10 GbE to ~55 m; 1 GbE to 100 m | 250 MHz | U/UTP |
| Cat6a | 10 GbE to 100 m | 500 MHz | F/UTP or U/FTP |
| Cat8 | 25/40 GbE to 30 m | 2000 MHz | F/UTP or S/FTP |
The reasoning behind each pick — the 10-Gigabit distance cutoff, why Cat7 is a marketing step, and the copper-vs-CCA problem — is in the full Ethernet guide. This selector is a sourcing starting point, not a substitute for a channel test on the installed link.
Frequently asked
What Ethernet category do I need for 10 Gigabit?
Cat6a — it carries 10GBASE-T the full 100 m channel. Cat6 manages 10 Gigabit only to about 55 m under favorable conditions, so it is a short-run compromise, not a 10-Gigabit standard. For 1 Gigabit, Cat5e to 100 m is fully in spec.
When do I need shielded Ethernet cable instead of UTP?
Two cases: electrically noisy environments (industrial floors, dense EMI) and Cat6a/Cat8 runs where alien crosstalk matters — there F/UTP or U/FTP construction earns its cost. For standard office and commercial runs at Cat5e/Cat6, unshielded (U/UTP) is the normal, in-spec choice.
Is Cat8 worth it for an office network?
No. Cat8 is a data-center, in-rack cable — 25/40 Gigabit to only 30 m over two connectors. For offices and horizontal runs the right ceiling is Cat6a (10 Gigabit to 100 m). Buying Cat8 for an office pays for reach and bandwidth the run can never use.
Sources
- Twisted-pair cabling categories (Cat5e–Cat8)ANSI/TIA-568
- Ethernet physical layers (1000/10G/25G/40GBASE-T, PoE)IEEE 802.3
Sourced to a real channel spec — in bare copper.
Kestner builds Cat5e through Cat6a patch and bulk cable to the category you actually need — bare copper, the right jacket rating, and cable verified to spec — from a US company that stands behind the paper.