Cat6 vs Cat6A: bandwidth, 10 gigabit distance, PoE and fire ratings
Published Sep 30, 2026
Cat6 and Cat6A both run gigabit Ethernet to 100 m without trouble. The difference shows up at 10 Gb/s and with high-power PoE. Cat6A carries 10GBASE-T over the full 100 m channel, while Cat6 is only good for about 55 m at that speed. For new horizontal cabling that has to last, Cat6A is the better buy. Cat6 still makes sense for gigabit runs in tight pathways.
The standards behind them
Both categories are defined in ANSI/TIA-568.2-D, the balanced twisted-pair cabling standard.
- Cat6 is specified to 250 MHz.
- Cat6A (augmented Category 6) is specified to 500 MHz, with added limits on alien crosstalk, the noise that couples between neighboring cables in a bundle.
10GBASE-T (IEEE 802.3an) needs that extra bandwidth and crosstalk margin. Over Cat6 it works to about 55 m, and even that depends on how badly the cable is bundled. Over Cat6A it is specified for the full 100 m channel: 90 m of permanent link plus patch cords.
Side by side
| Cat6 | Cat6A | |
|---|---|---|
| Standard | TIA-568.2-D | TIA-568.2-D |
| Bandwidth | 250 MHz | 500 MHz |
| 1000BASE-T | 100 m | 100 m |
| 10GBASE-T | About 55 m | 100 m |
| Alien crosstalk limits | None in the category | Specified |
| Outside diameter | Smaller | Noticeably larger |
| Common conductor size | 23 or 24 AWG | 23 AWG is common |
| Shielding | Mostly unshielded (U/UTP) | U/UTP or F/UTP both common |
| PoE heat in bundles | Runs warmer | Runs cooler at the same current |
| Price per foot | Lower | Higher, and heavier to pull |
Size and pathways
Cat6A is thicker and stiffer. Its extra separation between pairs, or its shield, is what keeps alien crosstalk down. The trade is fill: fewer cables fit in a conduit or on a J-hook, and bend radius needs more room at the rack and the outlet box. Check the outside diameter on the product's spec sheet before you size a conduit or count cables per hook.
Shielded or unshielded
Unshielded Cat6A (U/UTP) meets the category through cable design alone. Shielded Cat6A (F/UTP, with a foil around the four pairs) is thinner than many U/UTP designs and handles noisy spaces well, but it only works as a system. The jacks, patch panels and cords must be shielded too, and the shield must be bonded at the rack under the telecommunications bonding standard, TIA-607. A shielded cable terminated on unshielded jacks gains nothing.
PoE and heat
IEEE 802.3bt Power over Ethernet delivers up to 90 W at the power source equipment, over all four pairs. Current through a large bundle raises its temperature, and hotter cable loses signal. Larger conductors and a larger cable surface help, which is part of why Cat6A bundles run cooler than Cat6 at the same power.
The NEC also has a table for this. In the 2017 and 2020 editions, Table 725.144 limits the current per conductor by conductor size and bundle size when Class 2 or Class 3 power rides on data cable, unless the cable carries a limited-power (-LP) marking. The 2023 edition reorganized Article 725, so look the table up in your edition.
Fire ratings under the NEC
Data cable used in buildings has to carry a listing for the space it runs through. Communications cable types were in NEC Article 800 through the 2017 edition. Since the 2020 edition, communications circuits are in Article 805, with general requirements kept in Article 800.
- Plenum cable, CMP, for ducts, plenums and other air-handling spaces.
- Riser cable, CMR, for vertical runs between floors.
- General-purpose cable, CM, for other runs within a floor.
A higher rating can substitute for a lower one: CMP can go anywhere CMR or CM can, and CMR can replace CM. Not the reverse. Most Cat6 and Cat6A is sold as CMR or CMP.
Where each fits
- New office, school or health care horizontal cabling meant to outlast several rounds of network gear: Cat6A.
- Wireless access point drops, where newer access points want multi-gigabit speed and 802.3bt power: Cat6A.
- Short runs to desks, cameras and phones at gigabit speeds: Cat6.
- Residential and small office jobs with crowded pathways: Cat6, unless the owner wants 10 Gb/s.
Common mistakes
- Mixing categories in one channel. The channel performs to its weakest part, so Cat6A cable on Cat6 jacks is a Cat6 channel.
- Buying riser cable for a plenum ceiling.
- Terminating shielded cable without bonding the shield.
- Buying "Cat6E". TIA defines no such category. Judge that cable by the performance it states.
- Skipping certification. Test finished links with a field tester to TIA-1152-A before you hand the job over.
Shop data cable
- Cat6A riser and Cat6A plenum
- Cat6A shielded plenum and Cat6A shielded riser
- Cat6 riser and Cat6 plenum
- More in low voltage and fiber optic cable for backbone runs
Check the project spec, the equipment maker's cabling requirements and the listing printed on the jacket before you order.