An electrical junction box is a container for electrical connections, usually intended to conceal them from sight and deter tampering. A small metal or plastic junction box may form part of an electrical conduit wiring system in a building, or may be buried in the plaster of a wall, concealed behind an access panel or cast into concrete with only the lid showing. It sometimes includes terminals for joining wires. A similar container used for joining wires to electrical switches or sockets is called a pattress.
The term may also be used for a larger item such as a piece of street furniture. In the UK, this is sometimes called a cabinet. See Enclosure (electrical).
Junction boxes form an integral part of a circuit protection system where circuit integrity has to be provided, as for emergency lighting or emergency power lines, or the wiring between a nuclear reactor and a control room. In such an installation, the fireproofing around the incoming or outgoing cables must also be extended to cover the junction box to prevent short circuits inside the box during an accidental fire.
A junction box installed as part a photovoltaic system does not need to be listed to UL standard 1741 unless it is used as a solar combiner box.
Famous quotes containing the words junction and/or box:
“In order to get to East Russet you take the Vermont Central as far as Twitchell’s Falls and change there for Torpid River Junction, where a spur line takes you right into Gormley. At Gormley you are met by a buckboard which takes you back to Torpid River Junction again.”
—Robert Benchley (1889–1945)
“Franceska: I was happy in the life I built up for myself. I put a fine high wall of music around me and nothing could touch me. I was safe and secure. And then you had to come along and knock it all down and I hate you for that.
Maxwell: On the contrary, you love me.”
—Muriel Box (b. 1905)