The Basics of Electrical Cables - Home Office Wiring Tips

It was the 1880's when the first ever cables with insulation were made, the insulation was made of natural latex made from tree sap. The downside of this type of insulation was that it needed to be constantly wet or it would fail to insulate. In 1906 armoured cables were introduced, these were covered with flexible sheathing and two cloth covered, rubber insulated conductors. By the end of the second world war PVC was being tested for cable insulation and by the 50s it was commercially viable.

PVC replaced rubber cables especially in domestic applications. In the 70s paper insulated cables were replaced by heralded XLPE and in the 80s optical fibres were starting to be used for data transmission and condition monitoring. During this decade super conductive high temperature materials were discovered too and by the 90s these materials became widespread in extra high voltage, optical fibres used in overhead lines and EHV applications. Although nowadays there are various type of cables, they all share the same features and components.

Understanding cables

Wire Size (Gauge)

Cables come with different wire sizes when it comes to different appliances and devices. For more demanding appliances, be it an Helukabel cable or Igus cable, the gauge (diameter) of the wire needs to be of a lesser number. The lower the number of the wire gauge the greater the loads it can handle.

Sheathing

There are a lot of different sheathing materials but we are going to cover only the more popular ones. PVC (Polyvinyl Chloride) is a cost effective option which has excellent insulating properties whilst being stable, durable and robust. XLPE (Cross linked Polyethylene) is a widely used sheathing material for power cables which has better insulative properties than PVC as well as a higher current rating.

LSZH (Low Smoke Zero Halogen) is used in populated and enclosed areas such as trains, shipping and aircraft applications as it is made for areas with poor ventilation. Rubber sheathing is best for the outdoors and in wet environments since it is abrasion proof and can withstand rough treatment.

Colour Coding

Although not all cables are going to be colour coded, for those that are, it's good to know what you're looking at. First we need to understand wire colour coding. A bare or a green wire is the ground wire which lets the faulty current travel back to the panel in the event of a ground fault – this cuts off electricity since it blows the fuse.

Red or black wires are hot, which means they carry live current from the panel to a device. Although there are other colours for a hot wire they are not as common as black and red. White wires are neutral meaning they carry the current to the panel and complete the circuit.

The cable sheathing material can be colour coded too in order to quickly identify the gauge and the circuit amp ratings. A black cable is usually an 8 or 6 gauge with 45 or 60 amp circuit rating. Orange cables are a 10 gauge wire with a 30 amp circuit rating and yellow cables are 12 gauge wires with an 20 amp rating. White cables are 14 gauge wires that have a 15amp rating and grey cables are called underground feeder cables. 

Wiring

Cutting

When cutting a Helukabel cable, Igus cables or a Lapp cable the length shouldn't be longer than 90 m. The termination needs to be clean and cut with a cutter made for the cable at hand. Avoid using diagonal cutting pliers as they will crush the insulation and reduce the effectiveness of the cable.

Terminating

The termination, wire placement and the connectors need to be top notch. Take your time when putting the wires in the connectors and make sure you do so neatly without rushing things. Otherwise the transmission errors will be a common occurrence as well as reduction in speeds when it comes to network cables.

Stripping

Removing the cable jacket (outer sheathing) is not as easy as cutting the cable. Try not to turn the stripping tool too many times as this can cut too deep and damage the wires inside. If your tool takes a lot of turns in order to strip the cable you need to replace it or change your technique.

Cable Management

The easiest method and one that often springs to mind it to make a small loop and keep the cables together with the help of a twist tie. This isn't a bad idea but it is also not a very good one either. Loose cables make your desk look ugly and whilst some may recommend pushing the bundle of cables against the wall this is not ideal either.

You can make for a tidy space with a binder clip. Clip your USB, network and other electronics cables at the back edge of the desk and feed them through the metal hoops in the clamp. This way you'll have them anchored in a row. In order to have a cable stay away from the floor you can trap it by removing the clamp and positioning the cord into the hop of the binder before you slip the clamp back in the metal clip.

If you have a lot of cables, to the point where you forget which cable's for the printer and which one is for your custom-made keyboard then you simply need to label them. This will prevent you from rummaging through cables that all look the same. You can purchase cable labels or make your own. Wrap a bit of masking tape on the cable with a small tab of tape folded over it, then name the cable on that tab with a marker.

You can store cables used with portable devices, that aren't used as frequently as your VGA or HDMI cable perhaps, in a basket with inline handles. You can feed the already plugged in cables through the handles with the help of binder clips to anchor them. When you need to charge a power bank or any other portable device simply plug it in and leave it in the basket.