Data Network Cabling Installation - FTP Cables

Good cabling starts on paper, not in the wall. The electrician goes through where you will have your computer, TV, router or cameras, and plans the number of sockets and the cable routes from that.

1. Network design: the electrician chooses a spot for the cabinet or a small data enclosure, the positions of the RJ45 sockets and the routes. It makes sense to add spare capacity, for example a second socket behind the TV or a cable to the ceiling for a future Wi-Fi access point.
2. Preparing the routes: before plastering, chases are cut and conduit is laid. In plasterboard walls the cables run in the cavity behind the boards. When cabling is added to a finished room, surface trunking or cable channels are used.
3. Pulling the cables: each socket gets its own cable running all the way back to the cabinet. A spare length is left at both ends, usually a few tens of centimetres.
4. Termination: the cables are connected to the sockets and the patch panel using one wiring scheme, either T568A or T568B. With FTP, the shield must be connected to the metal part of the socket and the panel.
5. Earthing: the patch panel and rack are connected to the building's protective bonding. This connection is a job for a qualified electrician.
6. Testing and labelling: every link is tested, given the same number on the socket and on the panel, and the results are recorded in a test report.

Unshielded UTP cable works reliably in a quiet environment, such as a short run in a flat where the data cables do not sit right next to power cables. FTP pays off wherever data runs alongside the electrical installation: in blocks of flats with dense wiring, in offices and in plant rooms. The shield only helps when the whole link is shielded and properly earthed, though. A shielded cable terminated in an unshielded socket behaves like ordinary UTP.

For the category, a simple rule applies: a cable buried in the wall is hard to replace, so do not cut corners where nothing can be fixed later.

• Cat 5e handles gigabit connections, but these days it is rarely chosen for new cabling.
• Cat 6 is the usual choice for flats, houses and offices and leaves headroom for the future.
• Cat 6a suits you if you want speeds of around 10 Gbit/s over longer runs as well, or if you are building a network to last many years.

All parts of a link, meaning the cable, sockets, connectors and patch panel, should be the same category. Higher categories are thicker and stiffer, so they need wider trunking and a larger bending radius, as stated by the manufacturer.

In practice, data cables are almost always installed together with power cables, so it pays to plan both installations at the same time. Data and power cables should not lie tight against each other in the same chase. Ideally they follow separate routes, or run in separate compartments of a trunking system with a divider between them. The required separation depends on the cable type and on whether there is a divider. Rules for cable routes and structured cabling are set out in the European standards EN 50174 and EN 50173.

The cabinet or data enclosure needs access for servicing, ventilation and its own mains socket, possibly also a UPS. The socket, its circuit protection and the earthing of the rack must be done by a qualified electrician, and new electrical work is normally followed by inspection and testing under your local rules. If you want to power cameras or access points through the data cable (PoE), plan for it when choosing the cable and the switch.

In a block of flats, agree the work with the building management or the owners' association before cutting chases in shared areas or running cables through the corridor. Ordinary cabling inside a flat usually needs no permit. If the work would affect load-bearing walls or floors, check with your local building authority what the building regulations require.

Installation is simplest at the shell stage, when the walls are not yet plastered and the cables can go into conduit along with the other services. Plasterboard walls, an accessible suspended ceiling and short runs to the central point also make the work easier.

The job gets more demanding with:

• Retrofitting in a finished flat, where chases have to be cut into the plaster or a way found through existing conduit
• Concrete or brick walls and floors that need holes drilled through them
• Long runs across several floors and a large number of sockets
• A higher cable category, which is stiffer and slower to work with
• A requirement for testing with a report for every link

The same problems come up again and again, and they later show up as dropouts or slow connections.

• Unearthed shield: foil that is not connected gives no protection and can sometimes even make interference worse.
• Broken foil: the foil tears during stripping or termination, and the shield is no longer continuous.
• Mixing shielded and unshielded parts: an FTP cable in an unshielded socket loses the benefit of the shield.
• Poor termination: swapped pairs, mixing the T568A and T568B schemes, or too much untwisted conductor at the connector.
• Damage during pulling: bends that are too tight, a cable crushed by a clip or kinked at a corner.
• No labelling or test report: years later nobody knows which cable goes where, and tracing a fault takes a long time.

At handover, ask to see the test results and check a few things yourself:

• Every socket and patch panel port has the same clear label
• There is a plan showing where each cable runs
• Each link has a test result for wiring and cable performance
• The cable, sockets and panel are the same category and all are shielded
• The rack or patch panel is connected to earth
• The cables in the cabinet are neatly dressed and nowhere sharply kinked
• The sockets are firmly fixed and devices connect to the network without dropouts