Electrical Wiring Types, Colours, Sizes & Installations!

In an electrical system, a cable will mostly consist of three wires each with their own purpose. These wires are coloured to keep with the wiring colour codes and allow people to know which wire is which. A licensed electrician will know what each wire does, therefore, will operate with them effectively while following the Wiring Rules. 

The brown wire is the live wire which will bring electrical currents to electrical appliances. This live wire needs to be insulated and connected to the ground system to prevent electrocution. 

The neutral wire is blue and acts as a way for currents to leave the appliance in order to prevent electrical overloading. An overloaded electrical circuit will often cause wires to melt and other dangerous issues. 

The neutral wire is located towards the end of the circuit where the electricity would have flowed within the live wire. The chance of receiving a shock with this wire is low but the wire is extremely hot, which can cause fires if not insulated correctly. 

The final main wire in a cable is the earth wire which is green or yellow in colour. The grounding wires are extremely important in protecting appliances and systems for sudden electrical spikes. These wires are safer to touch, though it is still recommended to be cautious around them and not touch them. 

Read our article for further information on why earthing is important to protect electrical equipment and people.

Wire gauge is what measures the size of a wire through its diameter or cross sectional area. How much gauge a wire has will lead to how much current will be able to flow within the wire. This measurement will also govern the resistance of the wire and also the weight per unit of length. A wire size of 4 is larger than a wire size of 40, where 4-40 are the general wire sizes. 

Below is a guide on the wire size, its diameter and how much capacity it has.

A fully licensed electrician will be the person who installs wires into homes. Wires are often grouped together where cables are formed, these cables all having their own use. Each wire has a live, neutral and earth point in it while each will have additional endings or insulations built for different purposes. The main types of wires, or cables, installed into homes are:

• Non-metallic – this wire, when used in home electrical circuits, is often used for interior purposes. Drier conditions and environments are also more suited to the non-metallic wires. The shape of this wire is tubular while run through the walls and floors of the house. The appliances and devices used in house wiring systems are often made with this wiring unit. 
• Underground feeder – these nonmetallic cables run underground and are best suited to wetter environments. Outdoor fixtures, such as outdoor light fixtures, are given electricity through these wires as they are installed underground. The wires are insulated with thick, solid plastic and can also be used for major circuit wiring. 
• THHN/ THWN – these wires are mostly found in conducts where wires are bundled in plastic sheathing. These single conductors will have their own colour insulation and are protected by plastic conduits or tubular metals. They are mainly installed in areas which are unfinished or in places such as garages and basements. Another use of these wires is for short connections, such as hot water heaters or garbage disposers. 
• Low voltage – for circuits which have 50 or less voltage these wires are used. Such as sprinklers, doorbells, speakers and thermostats are the common usage of these wires. They are insulated while can be inside sheathing or twisted together. They can only be used for low voltage appliances and systems to ensure they do not break. 

Phone and data – these wires are specifically used for phone lines and wi-fi networks around the home. The telephone cables are connected with these wires and any data points use specific wiring. These wires are separate to general home circuit wiring and are used specifically for phone and data services.