In short
For most offices, Cat6 is the right specification: gigabit to every desk, 10 Gigabit on runs up to 55 metres, and the lowest sensible cost per point. Cat6a earns its premium when runs are long, the building is electrically noisy, or the cabling powers cameras and WiFi 6 or WiFi 7 access points.
The building and the desk plan decide, not the price list, which is why we specify after a survey rather than from a catalogue.
Every office fit-out reaches the same fork in the road: Cat6 or Cat6a. One is the workhorse of British offices. The other costs more, takes a little more skill to install, and in the right building is worth every penny.
The wrong way to choose is by the numbers on the box. The right way is to look at what the cable will actually be asked to do, in your building, over the years you will occupy it. That is the decision this guide walks through, the same way we walk it through on a survey.
The short answer: Cat6, unless the building says otherwise
For most businesses specifying structured data cabling today, Cat6 is the right starting point. It runs gigabit without breaking a sweat, gives a 10 Gigabit ceiling on shorter runs, and carries what most offices will realistically ask of it for years.
That is not the answer that sells the most cable, which is rather the point. Where the design allows it, a good installer will talk you down to the cheaper drum, not up to the dearer one. Cat6a exists for specific conditions, and when those conditions are present it stops being a luxury and becomes the correct specification. The job is knowing which building you are standing in.
What the two cables actually do
Both cables deliver up to 10 Gigabit. The difference is how far they carry it, and how they behave while doing it.
- Cat6 runs gigabit across the full 100 metres, and 10 Gigabit across roughly the first 37 to 55 metres of a run, depending on conditions.
- Cat6a, the a standing for augmented, holds 10 Gigabit across the whole 100 metres, with tighter construction that shrugs off electrical interference.
- Cat6a is a thicker, stiffer cable. It fills containment faster and takes more care to terminate, which is part of what you are paying for on the labour line.
On a 30-metre run to a desk, the two perform identically for almost everything an office does. The differences appear at distance, under electrical noise, and under sustained load from powered devices.
When Cat6a earns its money
Four situations reliably justify the upgrade:
- You are running WiFi 6 or WiFi 7 access points, which can make full use of a 10 Gigabit link back to the switch.
- You are powering devices over the cable, such as cameras, phones and access points, where the better construction handles the heat and keeps performance crisp.
- You are fitting out a building you will occupy for years and want the cabling to stay ahead of demand rather than become the reason for the next refit.
- You are in a busier electrical environment, a factory floor, a workshop, a plant room, where the shielding genuinely shines.
Two or more of those on one project and Cat6a is not a premium, it is the specification. This is also why warehouse and manufacturing fit-outs land on Cat6a more often than office ones.
When Cat6 is the right call
A standard office floor with runs under 50 metres, ordinary electrical surroundings and a mixed load of laptops, phones and printers gets everything it needs from Cat6, tested and certified.
Spending the Cat6a difference on that floor buys capability the building cannot use. The same money spent on an extra access point, a better switch or a tidier comms cabinet moves the network further. We would rather specify the cheaper drum and point the saving at the thing that is actually limiting you.
What about Cat5e and Cat7?
Briefly, because they bracket the decision rather than drive it. Cat5e still carries gigabit and existing runs that test clean are often worth keeping. Cable sold as Cat7 sits outside the standard categories and is usually higher-grade shielded Cat6a by another name; for projects that genuinely need more than 10 Gigabit, fibre optic cabling is normally the cleaner answer.
The full comparison across every grade, speeds, distances and where each belongs, lives on our network cable types page.
How this gets decided on a real fit-out
On a survey, three things settle the Cat6 versus Cat6a question in minutes: the longest runs on the desk plan, what the cabling will power, and what else shares the routes the cable will take. Containment matters too, because Cat6a is thicker and fills trays faster, which can change the containment line on the quote.
Where cabling left by a previous tenant tests clean against the standard your layout needs, we reuse it and take those points off the quote. And if you are budgeting the whole project rather than just the cabling, our guide to office IT fit-out costs sets out how the full number comes together, per point, per access point and per user.
How Core Comms can help
We design, install and certify Cat6 and Cat6a cabling for offices, warehouses and healthcare sites across the North West and West Yorkshire, with UK-wide delivery for multi-site clients. Installations are Fluke tested and carry 25 year manufacturer warranties through Excel and HellermannTyton, so the specification decision is backed for the life of the building, not just the invoice.
The sequence is the same on every job: survey, design, a fixed itemised quote naming the cable grade and why, then installation and handover with the test results.
If you are weighing up Cat6 against Cat6a for a fit-out, talk to our team or call 0330 838 1000, and we will read the building before recommending the drum.
FAQs
Is Cat6 or Cat6a better for a business?
Cat6a is the better choice when you want 10 Gigabit across full-length runs, you are powering devices over the cable, or you are future-proofing a building you will occupy for years. Cat6 is the right, economical fit for standard offices where runs are shorter and gigabit is plenty.
How fast is Cat6a compared with Cat6?
Both deliver up to 10 Gigabit. The difference is distance: Cat6 holds 10 Gigabit across roughly the first 37 to 55 metres of a run, while Cat6a maintains it across the full 100 metres and resists electrical interference better while doing it.
Do I need to replace my existing cabling?
Often not. If your current Cat5e or Cat6 tests clean and your speeds suit how you work, it is worth keeping, and we take reusable points off the quote. Upgrading makes sense when you are moving, refitting, or adding high-demand kit such as WiFi 6 or WiFi 7 access points.
Is Cat7 cable worth it for an office?
For a standard office, Cat6a delivers dependable 10 Gigabit with standard connectors at a friendlier price, which keeps the design simple. Cable sold as Cat7 sits outside the usual standards, and where a project genuinely needs more than 10 Gigabit, fibre is normally the cleaner answer.
Does Cat6a cost much more to install than Cat6?
The cable itself carries a modest premium, and the thicker construction takes more containment space and more care to terminate, which shows on the labour line. On a standard office the difference rarely changes the project; on long-run or high-density buildings it pays for itself in headroom.
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