Structured cabling

An office that grew a bit at a time usually has cables pulled through the suspended ceiling with no order, outlets with no labels and a switch on a shelf above the printer. It all works until something breaks. Then nobody knows which outlet goes to which port, and finding the fault turns into pulling cables out one by one.

The other common problem is runs that link at 100 Mbit/s instead of gigabit. The cause is usually a badly crimped connector, too much untwisted pair at the termination, or a cable bent at a sharp angle somewhere along the way.

Before anything is pulled we walk the space and agree where desks, printers, cameras and access points will go, including the ones that do not exist yet. An extra run laid now costs little. Pulling one through a finished wall later costs a lot more.

• Horizontal runs of up to 90 metres from patch panel to outlet, as the copper cabling standards require
• Data cabling kept apart from power cables, so interference stays out of the data lines
• Camera and access point runs planned for PoE power from the switch
• Every run tested with a certification tester: wiremap, length, near end crosstalk (NEXT) and return loss

At the end you get a test report for every run, a diagram of the outlet layout, and a rack where the patch panel, switch and power are arranged so you can see what is where. The label on the outlet matches the label on the panel, so a fault or a desk move is handled without guesswork.

The test report is worth keeping. If a run starts behaving oddly a few years from now, new measurements are compared with the old ones and it is immediately clear whether the cable has been damaged or the problem is in the equipment.