What is a wiring diagram?

Basically a wiring diagram is a drawing that shows all the wiring between parts such as control or signal functions, power supply and earth connections, and unused leads and termination contacts. Also, the wiring diagram shows the interconnections between terminal posts, blocks, plugs, sockets and lead-throughs. This wiring diagram will contain details such as terminal identification numbers that enable us to wire the unit together. The parts in the wiring diagram are shown only in blocks with no indication of the size or shape of the components. But it will only show the terminal number or connection number in the component.