
Electrical junction box in the process of installation.
Electrical conduit and
cables come together here for disposition.
An electrical 'junction box', is a container for electrical junctions, usually intended to conceal them from sight, and to some extent tampering. It can be a small
metal or
plastic container, such as those intended to form part of wiring, especially in
buildings; in this type of application, it may form part of an
electrical conduit wiring
system, 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 may or may not include terminals etc. 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, e. g. of street furniture; in UK, this is sometimes called a cabinet. See
Enclosure (electrical).
Junction boxes form an integral part of a circuit protection system. In the event
circuit integrity has to be provided, as may be necessary for emergency lighting or emergency power lines, or the wiring between a
nuclear reactor and a
control room. In such an event, the
fireproofing afforded to the incoming or outgoing cables must also be extended to cover the 'junction box' to prevent
short circuits inside of the box during an accidental
fire.
See also
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Bounding
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Electrical wiring
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Circuit integrity
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Fireproofing
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Passive fire protection
★
Cable
★
Cable tray
★
Electrical conduit
★
Short circuit
External Links
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NEMA: National Electrical Manufacturers Association
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IBEW: International Brotherhood Of Electrical Workers
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NECA: National Electrical Contractors Association