Guides/Installation
Installation
guide.
How to handle, route and terminate network cable so that it performs the way it was built to.
Network cable carries data, not mains power. Never connect it to an electrical supply, and never use a cable whose jacket is cut or crushed.
Bend it. Never fold it.
Almost every fault that shows up later starts at a corner. The two drawings below are the same cable at the same scale — the only difference is how tight the turn is.
A bend · 8 × D or wider
The pairs keep their spacing all the way round, so the cable performs on the far side of the corner exactly as it did before it.
A fold · anything tighter
The pairs are crushed against one another at the corner. The jacket springs back, the damage does not.
The wide turn is drawn at exactly eight diameters. D is the outer diameter of the cable, so the minimum radius travels with it: a thicker cable needs a wider turn.
Pulling
Pull by hand. A cable dragged hard round a corner stretches the conductors and loosens the twist.
Cut ends
Cut ends of bulk cable are sharp. Handle them with care.
A cable that fails months after it went in almost never failed on its own. The fold that caused it was made in the minute it was routed, and by then the jacket looks untouched from the outside — which is why the two minutes spent on the corner are the best two minutes of the whole job.
Give it room, and give it slack.
Away from power
Keep a separation from power cabling as required by the national rules where you are, and avoid running parallel to it over long stretches.
Slack at the ends
Leave a little at each end. A cable under tension pulls on its connector.
Seven steps, in this order.
This is what cable on a reel is for: you cut each lead to the length the route really needs and fit the plugs yourself. You need a wire cutter, a stripper, a crimping tool for modular connectors, and one RJ45 connector for each end.
-
Cut to lengthMargin at both ends
Use a wire cutter and allow margin at both ends. A cable under tension pulls on its connector for the rest of its life.
-
Strip the jacket25 mm
Remove about 25 mm without nicking the insulation of the pairs. A nicked conductor fails later, not now.
-
Untwist and order the wires13 mm maximum
Untwist each pair as little as you can and lay the wires out in the order of your chosen scheme. Keep the twist right up to the connector: past 13 mm the pair stops behaving like a pair.
-
Trim flatEqual length
Cut the eight wires square and to equal length, so they all reach the front of the connector together.
-
Insert into the connectorCheck the order
Slide the wires in keeping the order, until each one touches the front face. Check the order through the plastic before crimping — after crimping the connector is scrap.
-
CrimpFirm and complete
Use a crimping tool for modular connectors, and press until the contacts seat.
-
VerifyBefore use
Confirm every contact is seated and the jacket is gripped by the strain relief before the cable goes into service.
The twisting is what cancels interference, so wherever a pair is untwisted it stops protecting itself. The cabling standard allows 13 mm at the point of termination; on Category 6 it is worth staying under 10. Excess untwist is the most common reason a professionally installed link fails certification — and it is invisible once the connector is on.
A terminated cable arrives with the plugs already fitted, in fixed lengths from 1 to 100 metres. The reel earns its place when no fixed length fits the route, or when the run has to pass through an opening a moulded connector will not go through.
T568A or T568B —
and the same one at both ends.
Two pin assignments are in use and they differ only in that the orange and green pairs trade places. Either one works. One at each end gives you a crossover cable, which is not what a modern network expects.
White-green · Green · White-orange · Blue · White-blue · Orange · White-brown · Brown
White-orange · Orange · White-green · Blue · White-blue · Green · White-brown · Brown
Pin 1 is on the left with the clip facing away from you. Both schemes are drawn pin by pin, in colour, in Introduction to Ethernet Cables.
Three minutes that save an afternoon.
Label both ends
It costs a minute and saves an afternoon later.
Test before closing up
Check the link works before anything goes back behind a wall or a skirting board.
If it is intermittent
Suspect the terminations first. They account for most faults.
Cable, plugs, and the length you choose.
This page is general guidance. The instructions supplied with a product, and published at Instructions for Use, are what govern that product.