All the different electrical cables in your home have different purposes. Each cable is tailor-made for a specific use. Every cable carries an electrical current with a specific voltage limit. They contain cores made up of copper wires coated with insulated plastic and colour-coded to match their purpose, either neutral, live or earth. These cores are then surrounded by a layer of tough, insulated plastic. It’s important to use the correct cable for the correct purpose or an electrical fire could ensue.
Twin-core and earth cables.
All of the power cables inside your home will probably use twin core and earth cables. This type of cable is made up of two cores with a PVC outer sleeve for insulation, and an earth core in between them. The live core has a brown sleeve and the neutral core has a blue one. The earth core has a green and yellow sleeve. For domestic internal cables Australia uses this system.
Two-way light fittings are controlled by two switches which use three core cables and earth to connect the two switches. The cable is made up of 3 individually insulated solid cores of brown, black and grey, with a bare earth core surrounded by PVC sleeving.
Steel Wired Armoured (SWA) cable.
Steel Wired Armoured (SWA) cable is used outside the home either underground or overhead with a catenary wire. This type of cable is made up of two to four inner cores, depending on its purpose, individually sleeved, then surrounded with a layer of plastic sleeving covered with a layer of protected wire armour. It has another final outer layer to complete the job. Because of the multiple layers of protection, SWA cable is not very flexible, but if flexibility is required there are other outside cabling options.
The portable electrical appliances and light pendants in your home will more than likely use flex cables to allow you to make flexible connections. The cable is made in a cross-section, with 2 or 3 cores surrounded by a PVC outer sleeve. Flex cables offer a greater capacity to bend, but also straighten out easily without damage.
Risks and dangers of old electrical cable.
If you find any electrical cables around your home that appear to be old, or damaged, or do not comply with the descriptions given above, it would be wise to call a registered electrician to make a thorough inspection and then replace what needs replacing. You can keep an eye out for older, discontinued wiring colours, rubber insulated cables, two-core multi-strand cables with an outer lead cover, and any red and black cables. These are the clearest signs your wiring probably needs to be replaced. The reason for this is that rubber insulation normally degrades and breaks down over time, which increases the chances of an electrical fault. If the insulation around electrical cables becomes damaged or tears, you could well be at risk of an electrical house fire which your insurance policy may not cover.