Cabling is the least interesting part of a network and the part most likely to cause a fault nobody can explain. It also lasts longer than everything else you install, which makes it the wrong place to save money.
What to specify
Cat6 is the sensible default for a business office. It handles gigabit comfortably and 10 gigabit over shorter runs, and the cost difference from older grades is small.
Cat6A costs more, is thicker and harder to route, and supports 10 gigabit over full-length runs. Worth considering if the building is being cabled once for a long horizon, or where you expect high-bandwidth links between floors.
Fibre for links between buildings, between floors in larger premises, or anywhere the distance exceeds the hundred-metre limit of copper. Also the correct answer where there is an electrical isolation concern, such as between separate buildings with separate earths.
Do not install anything below Cat6 now. The saving is trivial and you will be living with it for two decades.
The rules that prevent intermittent faults
The faults that cost the most to diagnose are the ones where the cable mostly works.
Do not exceed one hundred metres. That is the total from switch to socket including patch leads, not just the fixed run.
Do not untwist more than necessary at terminations. The twisting is what rejects interference. Thirteen millimetres of untwisted pair at a socket is the limit, and rushed terminations routinely exceed it.
Do not exceed the bend radius. Cable pulled tight around a corner is damaged internally even though it looks fine.
Do not run parallel with mains. Interference induced from power cabling causes errors and retransmissions. Crossing at right angles is fine; sharing trunking is not.
Do not overtighten cable ties. Deforming the cable changes its characteristics.
Do not pull too hard. Exceeding the tension rating stretches the conductors, and the damage is invisible.
Every one of these produces a cable that works on a quiet day and fails under load, which is the hardest category of fault to find.
A cable that passes traffic is not the same as a cable that meets specification. The difference shows up months later, at the worst time, as something intermittent.
What to insist on from an installer
Certified test results for every run
Not a continuity check with a cheap tester — a certification test measuring the electrical characteristics against the standard, with a printed or digital result per run.
This is the single most important thing to require. It proves the installation met specification on the day, and it gives you something to compare against if problems appear later.
Labelling at both ends
Every outlet labelled, matching a label on the patch panel. Consistent, permanent, and recorded on a schedule.
Unlabelled cabling means every future fault begins with somebody tracing cables by unplugging them, which is exactly how outages are caused during troubleshooting.
A proper cabinet
Patch panel, switches, and space to work. Cables dressed and managed rather than hanging in a bundle. Lockable, ventilated, and somewhere that is not a cleaning cupboard or under a sink.
A tidy cabinet is not vanity. It is the difference between a five-minute change and an hour of tracing.
As-built documentation
A floor plan showing outlet positions and their labels, the patch panel schedule, and the test results. Handed over as a deliverable, not left with the installer.
How many outlets
More than you think, and put them where people will actually be.
Two outlets per desk position is the usual guidance. Additional outlets in the ceiling for wireless access points, positioned by coverage need rather than convenience — see office wi-fi.
Then outlets for the things people forget: printers, the meeting room display, the door entry panel, cameras, the till, the building controls. Each of these otherwise ends up on a long lead or on wireless it should not be on.
The incremental cost of an extra outlet during an installation is small. Adding one afterwards means an engineer, a day, and disruption.
Power over Ethernet
Delivering power over the same cable is now standard for access points, cameras, IP phones and door entry equipment. It removes the need for a power socket at every device position, which is what makes sensible placement possible.
Plan for it: switches with adequate power budget, and a cabinet with an uninterruptible power supply so that a brief power interruption does not take out the phones and the cameras simultaneously.
When it is worth recabling
If you have unlabelled cabling of unknown grade, installed by unknown people, with no test records and intermittent faults — recabling is often cheaper than continuing to diagnose it.
Also worth doing during any building work. Cabling installed while walls are open costs a fraction of cabling installed afterwards.
Our infrastructure team installs and certifies structured cabling across Suffolk and Norfolk, with test results and documentation handed over. Start a conversation.
