The right Ethernet cable supports the application, route and equipment you actually have, with room for a realistic upgrade. A higher category can provide useful headroom, but it cannot make a gigabit switch deliver 10 Gb/s or increase the speed of your internet connection. Start by separating a replaceable patch lead from permanent wiring: the latter deserves more planning because changing it may mean reopening walls, ceilings or occupied work areas.
Compare the application, not just the category name
Ethernet performance depends on the whole installed channel: cable, connectors, patch leads, length and workmanship, together with the equipment at both ends. The following references help narrow a specification; they are not a guarantee for an untested run.
Swipe sideways to view all columns
| Category | Useful planning reference | Typical reason to choose it |
|---|---|---|
| Cat5e | 1 Gb/s over a compliant channel up to 100 m | Maintaining an existing gigabit network or making a straightforward equipment connection |
| Cat6 | 1 Gb/s to 100 m; 10 Gb/s on shorter suitable channels, often described as up to 55 m | New general-purpose wiring where full-distance 10 Gb/s is not specified |
| Cat6A | 10 Gb/s over a compliant channel up to 100 m | Defined 10 Gb/s requirements and permanent routes that are difficult to replace |
Some equipment supports 2.5 or 5 Gb/s over suitable existing Cat5e or Cat6. Check the exact equipment and installed channel rather than assuming every intermediate rate is supported.
Technical references: Cisco: Catalyst 9200 multigigabit cabling guidance · Fluke Networks: 10GBASE-T field testing requirements
Understand a permanent link and a complete channel
A permanent link is the fixed cabling between its termination points, usually a patch panel and an outlet. The channel adds the cords used to connect equipment at either end. For a conventional design, plan no more than 90 m of permanent link within the usual 100 m total channel allowance.
That is a planning model, not permission to add any ten metres of cords. Small-diameter patch leads, longer flexible cords and temperature conditions can require different allowances. Follow the cable-system guidance and applicable test limits. Measure the managed route, including vertical rises and service lengths, rather than the straight-line distance between rooms.
A Cat6A drum alone does not create a Cat6A channel. Lower-rated jacks, unsuitable patch leads, poor terminations or damaged cable can prevent the finished installation meeting the intended performance.
Technical references: Leviton: Guide to small-diameter patch cords · ISO: ISO/IEC 11801-1 generic cabling: scope and current amendments
Three buying scenarios
These are illustrative decisions rather than universal product prescriptions. In the office example, the extra material cost of Cat6A may be easier to justify while routes are open than after occupation. Conversely, replacing every accessible patch lead with a higher category will achieve little if the equipment and fixed cabling already meet the requirement.
Swipe sideways to view all columns
| Situation | A sensible starting point | Check before buying |
|---|---|---|
| Replace a 2 m lead between a gigabit router and a computer | A suitable factory-terminated Cat5e or Cat6 patch lead | Both ports, managed length, connector clearance and whether the fault is actually the lead |
| Install new office outlets for gigabit devices | Compare a complete Cat6 system with Cat6A against the upgrade plan | Route access, planned speeds, PoE devices, containment, termination and testing requirements |
| Install a permanent copper link that must support 10 Gb/s | A compatible Cat6A channel designed for the actual route | Endpoint support, total channel length, environment, system components and acceptance testing |
Why the Cat6 55 m figure needs care
Cat6 offers more crosstalk margin than Cat5e, but 10GBASE-T introduces another concern: interference from neighbouring cables, called alien crosstalk. Bundle layout, component performance and installation quality matter alongside length. The often-quoted 55 m figure is conditional, not a universal pass/fail boundary.
Fluke's guidance describes different expectations within the 37–55 m range and the need to assess the installed channel. A short run is not automatically a certified 10 Gb/s link. If an existing Cat6 installation is to carry 10 Gb/s, have the relevant performance assessed. For a new installation with a firm full-distance 10 Gb/s requirement, Cat6A avoids designing around that conditional Cat6 reach.
Technical references: Fluke Networks: 10GBASE-T field testing requirements
Category and shielding are separate choices
Cat6A is available in different constructions; the category does not automatically mean a shielded cable. Read the letters around the slash to identify the overall screen and the individual pair screens. Do not substitute a different construction solely because both products say Cat6A.
A screened design needs compatible connectivity and an appropriate bonding arrangement. It also has physical consequences: cable diameter, bend radius, termination space and pathway fill vary between products. A correctly designed unshielded system can be appropriate; adding a screen is not a substitute for sound routing and installation.
Swipe sideways to view all columns
| Marking | Overall screen | Individual pair screen |
|---|---|---|
| U/UTP | None | None |
| F/UTP | Foil | None |
| U/FTP | None | Foil |
| F/FTP | Foil | Foil |
| S/FTP | Braid | Foil |
Technical references: Belden: Cable shielding constructions explained
Conductor, sheath and fire classification: read all three
Use suitable solid-conductor installation cable for fixed runs and purpose-made flexible patch leads for equipment connections. Check the conductor size, insulation diameter and solid/stranded compatibility of the actual termination hardware. A plug that physically accepts a cable is not necessarily specified for that construction.
Confirm conductor material. CCA means copper-clad aluminium; it is not the same material as copper and its increased resistance is a particular concern for power delivery. Do not treat an inexpensive CCA lead as an equivalent replacement for a specified copper channel, especially for PoE.
Cca, when used as a reaction-to-fire class, means something entirely different from CCA conductor material. Likewise, an LSZH description concerns smoke and halogen behaviour and is not itself a complete fire-classification specification. Confirm the full required classification with the project designer and check the product documentation.
Choose the sheath for the actual route. An indoor cable does not become UV-resistant, water-resistant or suitable for direct burial because it has a higher category or an LSZH jacket. For outdoor transitions or other demanding environments, establish the installation requirements before choosing a product.
Technical references: Fluke Networks: Copper-clad aluminium cable and resistance · Leviton: Cable fire classification and product documentation
Common questions before placing an order
- Will Cat6A make my internet faster? Only replacing a limiting part of the connection can improve performance. The internet service, router, switch and device can each be the bottleneck.
- Can a Cat6A patch lead connect to a Cat5e outlet? A suitable RJ45 lead can physically connect, but it does not upgrade the fixed link or guarantee Cat6A channel performance.
- Should working Cat5e be removed? First identify the required speed, power and condition. If it supports the application, replacement may offer no immediate benefit.
- Is a reel the same as a long patch lead? No. Installation cable is selected and terminated as part of a fixed system; a patch lead is a finished flexible assembly for its stated use.
- Does a higher category guarantee PoE suitability? No. Power type, channel resistance, connections, bundle temperature and manufacturer guidance still matter.
Turn the requirement into an accurate order
Record the required application before choosing a part number, then confirm the route, compatible components and acceptance test. Keep installation cable, patch leads and termination hardware on separate lines so quantities and specifications are not confused. For a repeat order, use the existing product reference as well as its description; similar names can hide different shielding, sheath or pack sizes.
For a small replacement, the correct connector, length and listed specification may settle the choice. For a project, resolve missing design information before treating an alternative as equivalent. That keeps both modest purchases and larger orders tied to the actual requirement.
Explore the components covered in this guide
Compare the listed specifications with your equipment and installation requirements before choosing.
Before you buy or send a project enquiry
For a replacement lead or a larger installation, keep these details together so you can compare the listed specifications accurately:
- Required link speed, endpoint models and any PoE requirement.
- Installation cable or finished patch leads, with routed lengths and quantities.
- Category, shielding, copper conductor construction, sheath and specified fire classification.
- Compatible panels, jacks or plugs, plus known product references and delivery requirements.
Our business and project orders page explains what to include in an enquiry and where to check the current ordering and delivery terms. If a specification is unknown, say so rather than choosing a substitute by appearance.
Sources and further reading
This guide was checked against the following standards and technical resources. Product capabilities can change, so confirm the current manufacturer specification before designing an installation.
- Cisco: Catalyst 9200 multigigabit cabling guidance
- Fluke Networks: 10GBASE-T field testing requirements
- Leviton: Guide to small-diameter patch cords
- ISO: ISO/IEC 11801-1 generic cabling: scope and current amendments
- Belden: Cable shielding constructions explained
- Fluke Networks: Copper-clad aluminium cable and resistance
- Leviton: Cable fire classification and product documentation
This article provides general technical guidance, not a site-specific design. Follow current product instructions and applicable building, electrical and fire requirements; use a competent installer where needed.