By Susan Feldman on February 13 2018 23:21:11
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.
Special versions of non-metallic sheathed cables, such as US Type UF, are designed for direct underground burial (often with separate mechanical protection) or exterior use where exposure to ultraviolet radiation (UV) is a possibility. These cables differ in having a moisture-resistant construction, lacking paper or other absorbent fillers, and being formulated for UV resistance.
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.
Unlike a pictorial diagram, a wiring diagram uses abstract or simplified shapes and lines to show components. Pictorial diagrams are often photos with labels or highly-detailed drawings of the physical components.
wiring diagram samples
wiring diagram schematics
3 way switch wiring diagram