During a new installation, the electrician should attach appropriately-coloured insulation, sheathes, or sleeving to the different wires to enable easy identification of the corresponding wiring. As previously mentioned, the old-style black neutral wiring has been replaced with blue. Similarly, red live wiring is now brown. If there is any mixing of old and new wiring colours, then the cables should be clearly marked with the relevant colour codes to prevent the incorrect application of the phase and neutral.
Some cable varieties in the UK have similar colouring to mains wiring. As an example, TV aerial cables don’t carry any voltage but do have the same brown colour as the live mains cabling. It is also common to find black wire or cabling trailing behind the TV. This is the same colour as the old neutral wire. However, if there is any doubt, you should arrange for a professional electrician to carry out an inspection to ensure safety.
It is also important to be aware of the difference between single and three-phase wiring. The single-phase connection is formed of two wires, with the three-phase variety being formed of three or four wires. The single-phase connection allows for the relatively easy balancing of electrical loads via the network. Due to the increased power generation, the three-phase connection is better suited to connection within workplaces featuring a variety of electrical machines and equipment. You can identify either the two or three-phase connection by counting the wires connected with the electrical service panel.
A single-phase connection will feature dual black or red live wiring and blue neutral wiring. There is a voltage difference of 230V between the wires. Either three or four wires will be connected to an electrical service panel functioning via the three-phase system. This will feature three live wires of either a black, red, brown or grey colour and a separate blue wire. There will typically be a 400V separation between the two live wires. It is important that you do not make the mistake of confusing the natural blue and green/yellow earth connection when referring to the electrical system.