What Is a CAT8 Cable? Types and Selection Criteria
A CAT8 cable is an S/FTP cable with each pair individually screened, made for 25 and 40 Gbit/s Ethernet on short server-to-switch links in data centres.
A CAT8 cable is a twisted-pair network cable that works up to 2000 MHz and is made for 25 and 40 Gbit/s Ethernet (25GBASE-T, 40GBASE-T) on short links between servers, storage and switches in data centres. To prevent crosstalk at high frequency, each pair is screened with foil and all pairs together with a braid (S/FTP). At these speeds the channel length is at most 30 m; longer horizontal cabling uses CAT6A or CAT7.
Cat 8.1 and Cat 8.2
| Class | Connector | Note |
|---|---|---|
| Cat 8.1 (Class I) | Compatible with RJ45 | Backward-compatible use with existing RJ45 infrastructure |
| Cat 8.2 (Class II) | High-performance non-RJ45 connectors | S/FTP cable construction; connector choice depends on the system |
The Reçber SL2000 cables in the catalog are listed as Category 8.2 S/FTP 4x2x22AWG in their names. Choose connectors and patch panels that match the cable's class.
Selection criteria
- Distance and speed: 25/40 Gbit/s is defined only for channels up to 30 m. For long runs within a floor or building, CAT6A or CAT7 is more suitable and economical.
- Reaction to fire (CPR): The class of cable installed permanently in a building is declared according to EN 50575. The three cables in the catalog are Dca-s1a,d2,a1, Cca-s1a,d1,a1 and B2ca-s1a,d1,a1; choose the class your specification requires. B2ca is the highest and Dca the lowest of these.
- Screen and earthing: The screen of an S/FTP cable must be continuous through connectors and patch panels and bonded to the rack earth.
- Sheath and installation: An LSZH sheath gives off no halogen gas when burning. A cable with 22AWG conductors is thicker and stiffer; plan the bending radius and duct fill accordingly.
Common mistakes
- Using CAT8 on a long horizontal run: Beyond 30 m, 25/40 Gbit/s is not achieved; cost rises without benefit.
- Using unscreened connectors or patch panels: Screen continuity breaks and performance drops at high frequency.
- Not checking the CPR class: Cable below the class the specification requires may have to be replaced at inspection.
CAT8 cables at Welibaba
The CAT8 Cables category has 3 active products from the Reçber Kablo SL2000 range: LSZH (Dca), LSZH-Cca and LSZH-B2ca; all are S/FTP 4x2x22AWG, sold by the metre and listed with prices. For a comparison of categories, see the Ethernet LAN cable guide.
Frequently asked questions
Is CAT8 cable needed in a home or office network?
Usually not. Office and home networks commonly run 1 and 10 Gbit/s, for which CAT6 and CAT6A are enough. CAT8 is for short server-to-switch links in data centres.
How long can a CAT8 cable run be?
For 25 and 40 Gbit/s the channel length is at most 30 m. These speeds are not achieved on longer runs.
Can CAT8 cable be used with RJ45?
Cat 8.1 is compatible with RJ45. Cat 8.2 is defined for high-performance non-RJ45 connectors; for the Cat 8.2 cables in the catalog, choose connectors according to your system.