Junction box

An electrical junction box is an enclosure housing electrical connections, to protect the connections and provide a safety barrier. An electrical junction box is an enclosure housing electrical connections, to protect the connections and provide a safety barrier. A small metal or plastic junction box may form part of an electrical conduit or thermoplastic-sheathed cable (TPS) wiring system in a building. If designed for surface mounting, it is used mostly in ceilings, under floors or concealed behind an access panel - particularly in domestic or commercial buildings. An appropriate type (such as that shown on the right) may be buried in the plaster of a wall (although full concealment is no longer allowed by modern codes and standards) or cast into concrete - with only the cover visible.