A power cable is an electrical cable used specifically for transmission of electrical power. It is an assembly of one or more electrical conductors, usually held together in a single bundle with an insulating sheath, although some power cables are simply rigged as exposed live wires. Power cables may be detachable portable cords (typically coupled with adaptors), or installed as permanent wirings within buildings and structures, buried in the ground, laid underwater or run overhead. Power cables that are bundled inside thermoplastic sheathing and that are intended to be run inside a building are known as NM-B (nonmetallic sheathed building cable).
Small flexible power cables are used for electrical devices such as computers and peripherals, mobile devices, home appliances, light fixtures, power tools and machinery, as well as household lighting, heating, air conditioning and rooftop photovoltaic and home energy storage systems. Larger power cables are used for transmission of grid electricity to supply industrial, commercial and residential demands, as well as a significant portion of mass transit and freight transport (particularly rail transport).
