What is structured cabling? Getting it right from the start in a new building

What exactly does structured cabling mean?

In the traditional method each system runs its own cable: the phone installer runs the phone line, the camera installer runs the camera cable, and whoever sets up the internet runs a few cables from the modem to the rooms. A few years later there is a pile of cables in the ceiling and nobody knows who ran what.

In structured cabling, the building is cabled with a road map. A distribution point (cabinet) is set for each apartment, each office or each floor. Each outlet on the wall is connected by a single-piece cable to a distribution panel (patch panel) in this cabinet. Each port of the panel and each outlet on the wall is labeled with the same number. Whether an outlet will feed a computer, an IP phone or a camera is decided in the cabinet with a short patch cable.

This layout is based on international standards. The ISO/IEC 11801 family and its European counterpart EN 50173 describe the cable type, distance limits, and the layout of outlets and panels. A line run in line with the standard works the same way whichever brand of device is plugged in.

Why does it matter for the contractor?

The value of an apartment or an office floor is now also determined by its internet and smart-system infrastructure. The buyer wants to see a network outlet behind the TV in the living room, another in the bedroom, and an outlet in the ceiling for a wireless access point. If these are left in during rough construction along with the conduit, the cost is low. If they are added after the finishing work, it means cable ducts, plaster repair, paint and an unhappy buyer.

In commercial buildings the situation is clearer. The office layout changes as tenants change. On a floor with structured cabling, the new tenant only changes the connections in the cabinet. On a randomly cabled floor, each tenant opens up the ceiling again.

In housing estate and residence projects, the same infrastructure also carries cameras, access control, video door phones, parking barriers and the central satellite system. If instead of running separate cables for each of these systems a common conduit and cabinet layout is set up, subcontractors on site do not spoil each other's work and the building management works with a single map. The shared plan must have someone responsible; otherwise each team runs its own cable by the shortest route.

What should be done at which stage of construction?

Structured cabling is not done in one go but progresses in parts following the flow of construction. Missing the order is the most common mistake.

• Design stage: outlet locations, cabinet location and cable route are drawn together with the architectural and electrical project.
• Rough construction: conduits, junction boxes and floor crossings are left in the walls and slabs; pull wires are run through the conduits.
• Before plastering: cables are pulled, their ends are protected, and each cable is numbered at both ends.
• After the finishing work: outlet and panel terminations are made and the cabinet is installed.
• Before handover: every line is measured with a tester, and the results and outlet plan are added to the handover file.

Expert note: Always leave a pull wire inside the conduits and choose the conduit diameter for one more than the number of cables. Adding cables later to a full conduit is often impossible.

Cabinet location and power needs

The cabinet is the network hub of the building. In homes, a small wall-type box is installed in each apartment, or a floor cabinet in the stairwell; in commercial buildings, one cabinet on each floor and a main distribution room in the basement. With copper cable, the cable distance between the cabinet and the farthest outlet must not exceed 90 meters; this limit determines the number of cabinets.

The cabinet location needs to be ventilated, free of damp and lockable. A socket line fed from a separate fuse and an earthing line must be run to the cabinet. A stuffy cupboard under the stairs, in a Şanlıurfa summer, makes the switchdevices overheat and lock up. Leaving a ventilation grille or power for a small fan at the cabinet location prevents this problem from the start.

Which cable, how many outlets?

For new buildings, Cat6 is the common choice today. In offices and public buildings that will be used for many years, especially on the backbone lines between floors, Cat6A or fiber is planned. Links between buildings and between blocks are made with fiber.

Being stingy with the number of outlets costs more later. In a home, one network outlet for the living room, each bedroom and the study corner, one outlet in the ceiling for a wireless access point, and one line for the camera or video door phone at the front door is a good start. In offices, at least two outlets per desk are planned, with extra outlets in meeting rooms for the screen and camera.

Testing and the handover file

The last step of structured cabling is testing. Each line is measured with a cable tester; wiring order, breaks, short circuits and distance are checked. Higher-level certification testers also report whether the line really delivers Cat6 or Cat6A performance.

The handover file should contain the floor plan showing the outlet numbers, the panel port list and the test results. This file is given to the building management or the buyer. Years later, when there is a fault, it is the only map the technical team has.

Regulations and design

In new buildings, the BTK regulations on electronic communications installations and municipalities' project approval conditions include certain infrastructure requirements. Because these conditions vary with the type and date of the building, they should be checked with a licensed engineer during design.

Desa Bilişim can work with contractors at the project stage to prepare the conduit and outlet plan, and complete the cabling and testing together with the handover file. If you share your project's architectural drawings, we can determine the need together.

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