Structured cabling is core craft in modern installations. Here is twisted pair cabling Cat 5e/6/6A, 100 m channel, shielding, fibre, patch panels and connectors, PoE to IEEE 802.3, coax/antenna and equipotential bonding and separation from 230 V.
Introduction
Data and communications technology is one of the electrician training's specialisms. Structured cabling means laying a single, uniform, documented cable system that all communications (data, telephony, often also video and control) can run on — instead of a tangle of individual connections. The governing standards are the DS/EN 50173 series (the cabling system itself) and the DS/EN 50174 series (the installation).
Twisted pair cabling and categories
The backbone is twisted pair cable with four twisted pairs. The twisting eliminates noise and reduces crosstalk between the pairs — the tighter and more precise the twisting, the higher the category. The category indicates the bandwidth (MHz) the cabling is tested to, and thus how fast a connection it carries.
| Category | Bandwidth | Typical speed |
|---|---|---|
| Cat 5e | 100 MHz | 1 Gbit/s (1000BASE-T) |
| Cat 6 | 250 MHz | 1 Gbit/s; 10 Gbit/s only on short lengths |
| Cat 6A | 500 MHz | 10 Gbit/s for full 100 m |
Shading
Cable comes unshielded or shielded, marked with a code such as U/UTP (fully unshielded), F/UTP (foil around all pairs), S/FTP (braided shielding around cable + foil around each pair). Shielding helps in noisy environments (industry, close to 230 V), but REQUIRES properly grounded shielding at both ends and disciplined installation — a shield that is only grounded at one end or not at all does not work as intended.
Fibre
Where the distance is great, the speed very high, or where galvanic isolation is desired, optical fibre is used. Multimode (OM3/OM4/OM5) is typically used for shorter distances in buildings, singlemode (OS2) for long runs and backbone. Fibre does not conduct current, is immune to electromagnetic interference and creates no potential connection between buildings — an advantage in lightning protection and potential differences. Termination requires clean, correctly polished/spliced connections and measurement with OTDR/power meter.
Patch panels, cross-connects and jacks
Permanent cables are terminated in patch panels in a cross-connection field (distribution cabinet), from where you use patch cables to connect the individual port to a switch or equipment. At the other end is a data outlet (RJ45). The pairs are laid according to a fixed colour code — T568A or T568B — and the SAME code must be used at both ends of a straight cable. Keep the untwisting of the pairs at the termination as short as possible (typically max. ~13 mm for Cat 6), otherwise the high category is lost.
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