Building wire and cable carry electrical current from a power source to a device in a building, such as an outlet or light fixture. Building wire is typically run through conduit, cable trays, or raceways to run new circuits or extend old circuits inside walls and ceilings in commercial, industrial, and residential properties. Armored building cable consists of insulated wires bundled together and protected by a corrugated metal jacket that serves as a conduit and provides grounding. Nonmetallic sheathed building cable consists of three or more wire conductors (including one for grounding) bundled inside a jacket, or sheath.