By Stacy Calhoun on January 23 2018 20:49:13
A wiring diagram usually gives information about the relative position and arrangement of devices and terminals on the devices, to help in building or servicing the device. This is unlike a schematic diagram, where the arrangement of the components, interconnections on the diagram usually does not correspond to the components, physical locations in the finished device. A pictorial diagram would show more detail of the physical appearance, whereas a wiring diagram uses a more symbolic notation to emphasize interconnections over physical appearance.
Essential for pre-study works, the wiring diagram allows the cable list to be produced. If the wiring diagram is useful during the pre-study phase, it is also an important tool for the design of the installation functional scheme. Starting with the wiring diagram, the user can start producing his installation as a pre-study, and then launch his study during the installation cabling, allowing a reduced production time.
US single-phase residential power distribution transformer, showing the two insulated "Line" conductors and the bare "Neutral" conductor (derived from the earthed center-tap of the transformer). The distribution supporting cantenaries are also shown.
In a typical electrical code, some colour-coding of wires is mandatory. Many local rules and exceptions exist per country, state or region. Older installations vary in colour codes, and colours may fade with insulation exposure to heat, light and ageing.