Data cabling, rack builds and Fluke testing.

Data cabling is the part of a building nobody sees until it fails. A badly terminated link can pass a quick check and still cause slow networks, dropped Wi-Fi and cameras that stop at random. SEG’s engineers are trained in structured cabling, we build the racks, and we prove every link with our own Fluke certification tester before we hand over.

What we do

• Cat6 and Cat6A structured cabling for offices, warehouses, schools, retail and housing, installed neatly and labelled to a scheme you can follow.
• Rack and cabinet builds: patch panels, cable management, switches, power and UPS, built to be serviced years later.
• Fibre: links between floors and buildings, with terminations and trays dressed properly.
• Fluke certification testing of every link we install, with the results handed over.
• Testing of existing cabling, so you know whether what you have is sound.
• Containment, power and bonding from our own electricians, so cabling and electrics are installed together by one team.
• Cabling for Wi-Fi and CCTV, where the cabling decides how well the system performs.

We work from our head office in Chiswell Green, St Albans, across Hertfordshire, Bedfordshire, Buckinghamshire and North and West London. Call 01727 238 999 or send us your plans. Working near Stevenage? See data cabling in Stevenage.

Rack builds: where a cabling job is judged

Open a comms cabinet and you can tell how the whole job was done. Cables dressed in groups, every port labelled, power and UPS planned, room to add equipment later: that is a rack built by someone who expects to be called back in five years and wants to be able to find things. A tangle of patch leads is the opposite, and it is usually a sign that the cabling behind it was not tested either.

What is Fluke testing?

Fluke Networks makes the certification testers used across the cabling industry. A Fluke test sends signals down each installed link, measures how it performs and compares the result with the standard for the cable category. The tester then records a PASS or FAIL for that link, with the measured figures, and the results are saved to a report.

It matters because most faults cannot be seen. A cable can have the right colours on the right pins and still fail on crosstalk or signal loss because it was untwisted too far, kinked, over-stretched or poorly terminated. A cheap tester will not show that. A certification tester will.

A full test report for a link normally shows the wire map, the length, insertion loss, near-end crosstalk (NEXT), return loss and the margin (headroom) over the limit, along with the standard used, the date and the tester’s serial number. That is the evidence that a link is genuinely good.

What does a Fluke tester cost?

A lot more than most people expect. At the time of writing, a UK supplier lists a new two-module Fluke DSX-5000 certification kit at about £11,600 plus VAT (roughly £13,900 with VAT). Other kits are priced higher or lower depending on the modules, and the tester also needs regular calibration, software and trained operators. A basic cable tester that only checks the wires, by contrast, costs a few tens of pounds.

That gap is why many installers do not own one. We have invested in a Fluke tester because it is the only way to prove our own work, and the only way to show you it.

Do not hire an electrician without data experience and test equipment

An electrician who is excellent on power may never have terminated a data link, and a cabling job passed with a continuity buzzer is not certified. Whoever you use, ask these questions before you agree a price:

1. Do you own a certification tester, and which model?
2. Will every link be tested, or only a sample?
3. Will I receive the results, as a report from the tester’s software, not a handwritten tick sheet?
4. Which standard will the links be tested to, for example Cat6 or Cat6A?
5. Is the tester in calibration, and when does it expire?
6. Do the cable labels match the test results and a drawing of the building?
7. Who is trained to terminate and test, and will they be on site?
8. What happens if a link fails? The answer should be: we fix it and test again.

When the job is finished, ask for the evidence: the Fluke results for every link showing PASS, with the date, tester and standard on them. Keep them with your building records. If an installer cannot produce them, you have no proof the cabling meets the standard it was sold as. That applies to us as much as to anyone, and we are happy to be asked.

Cabling, electrics, Wi-Fi and CCTV in one place

Data cabling goes wrong where it meets power and containment: cables laid against mains, trays not bonded, cabinets with nowhere to plug in. Because SEG’s electricians and data engineers work together, containment, power and cabling are planned as one job. The same cabling feeds CCTV and AI cameras and business Wi-Fi from our group company SEGwifi, which only perform as well as the cable behind them.

Recent data cabling contracts

Real jobs from our records.

• St Bartholomew’s Church, St Albans: a new parish office with Cat6 data points, a wall-mounted data cabinet with PoE switch and PDU, and Wi-Fi across the buildings. See the project.
• Welwyn Garden City: a fibre link for a local business, September 2026.
• Dallas Burston Polo Club hotel, Warwickshire: 20 data points for a new guest block, radio links and cabinet maintenance. See the hotel project.
• 45 Pall Mall, London: comms rooms and patch panels labelled port by port for James Hambro & Partners.

Looking for a data cabling contractor in Hertfordshire? Every link is tested and labelled, and you get the results.

Questions people ask

Last updated 3 October 2026. Tester prices are a UK supplier’s list price at the time of writing and will change.