Structured cabling contractors — who to hire and what it costs

Structured cabling contractors design, install and certify office network cabling (Cat6, fibre) to standards such as ISO/IEC 11801; hire firms that provide UKAS-style test results and a clear workmanship warranty, and expect testing and labour to be the main cost drivers — not the cable itself.

Under‑specifying cable category

Choosing Cat5e instead of Cat6 (or singlemode instead of multimode fibre) to save a small sum today often forces expensive rework within a few years. The wrong category limits speeds, PoE capacity and future upgrades: a network that can’t support PoE++ or 10Gbps means upgraded switches and repeat cabling later, both disruptive and costly. When comparing quotes, ask for the exact cable standard (for example Cat6A or OM4), ask to see the proposed test limit and insist on a mention of ISO/IEC 11801 or BS EN equivalents in the specification. A good contractor will explain where a lower category is acceptable (meeting a defined business use) and where it isn’t.

Ignoring containment and future routes

Routing matters more than many owners realise. If cable trays, ducts or containment are not sized for future growth, adding points means cutting ceilings, moving fixtures and extended downtime. From our experience, structured cabling costs are dominated by labour — containment, cable pulls, terminations, testing — not the cable itself. Cable typically makes up 15-25% of a job’s invoice, which is why “while you’re here, add another six points” is cheap and “come back next month” is expensive. Ask contractors to show spare conduit capacity and a simple route plan; a tidy, labelled tray with spare space is insurance against costly returns.

Skipping test and certification

Some contractors supply a visual tidy install but stop short of full certification. Without documented cable test results you have no guarantee of performance and no leverage if faults appear. Look for delivered test reports showing pair-by-pair results, and a statement that links the tests to a recognised standard. Where appropriate, check suppliers supply both a continuity report and a full performance sweep and retention of test data for handover. If you want a single place to check warranty and service scope, see our cabling and data services which explain handover paperwork and post‑install support.

Fragmented installers with no single accountable contractor

Mixing electricians, a local IT firm and a separate cabling team often leaves nobody accountable for the whole run. That creates finger‑pointing when faults appear and can void warranties. Choose a structured cabling contractor who acts as the single accountable lead, coordinates site access, and issues a consolidated handover pack with test sheets and a labelled patch schedule. A clear lead contractor also simplifies scheduling around your business hours and reduces repeated site visits.

The cost of leaving these problems unfixed

Unresolved mistakes typically show up as repeated downtime, higher per‑point install costs, and lost productivity. The practical cost is not just the labour to rework cables but the switch upgrades, longer disruption windows and lost billable time while rooms are out of action. Practically speaking, doing the additional six points during the initial install is often a small marginal cost; returning later can be several times as expensive because labour is the dominant cost element. (See our networking wireless data electrical cabling guide.)

FAQ

What proportion of a cabling job is the cable itself in the UK?

Cable typically makes up 15–25% of a job’s invoice; labour, containment and testing make up the remainder, which is why adding points during the initial visit is usually far cheaper than returning later.

How can I check a contractor is competent and insured?

Ask for public liability and professional indemnity limits, examples of recent test reports tied to ISO/BS standards, a written warranty, and for references from similar office installs; genuine installers supply labelled handover sheets on completion.

Is it cheaper to add extra points now or later?

In most cases add them now: our experience shows the marginal cost of extra points during an install is small, whereas returning later multiplies labour, access and scheduling costs.

Will contractors provide certification after installation?

Legitimate structured cabling contractors should deliver test certificates and a patch schedule linking results to outlet IDs; keep those documents for troubleshooting and any warranty claims.