By Jennifer Mireles on January 30 2018 19:30:52
In North American practice, an overhead cable from a transformer on a power pole to a residential electrical service usually consists of three twisted (triplexed) conductors, with one being a bare neutral conductor, with the other two being the insulated conductors for both of the two 180 degree out of phase 120 V line voltages normally supplied. The neutral conductor is often a supporting "messenger" steel wire, which is used to support the insulated Line conductors.
A wiring diagram is a simple visual representation of the physical connections and physical layout of an electrical system or circuit. It shows how the electrical wires are interconnected and can also show where fixtures and components may be connected to the system.
The best way to understand wiring diagrams is to look at some examples of wiring diagrams. Click on any of these wiring diagrams.
In European countries, an attempt has been made to harmonise national wiring standards in an IEC standard, IEC 60364 Electrical Installations for Buildings. Hence national standards follow an identical system of sections and chapters. However, this standard is not written in such language that it can readily be adopted as a national wiring code. Neither is it designed for field use by electrical tradesmen and inspectors for testing compliance with national wiring standards. By contrast, national codes, such as the NEC or CSA C22.1, generally exemplify the common objectives of IEC 60364, but provide specific rules in a form that allows for guidance of those installing and inspecting electrical systems.