Junction box
{{short description|Enclosure housing electrical connections}}
{{not to be confused|Box junction}}
{{Electrical Wiring Sidebar}}
An electrical junction box (also known as a "jbox") is an enclosure housing electrical connections.{{Cite web|last=|first=|date=25 February 2024|title=What is a Junction Box (Electrical Box)?|url=https://www.electricalknowledge.com/electricians-tools/junction-box/|archive-url=|archive-date=|access-date=|website=Electrical Knowledge}} Junction boxes protect the electrical connections from the weather, as well as protecting people from accidental electric shocks.
Functions of the junction box
A small metal, plastic or fiberglass 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, concrete or concealed behind an access panel—particularly in domestic or commercial buildings. An appropriate type (such as that shown in the gallery) 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.
It sometimes includes built-in terminals for the joining of wires.
A similar, usually wall mounted, container used mainly to accommodate switches, sockets and the associated connecting wiring is called a pattress.
The term junction box may also be used for a larger item, such as a piece of street furniture. In the UK, such items are often 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.{{cn|date=January 2025}}
Image:Junction box.jpg|Electrical junction box in the process of installation. Electrical conduits terminate at the sides and cables pass through or are joined inside the box.
File:Junction box2.jpg|A metal junction box
File:Australian Internal Surface Mounted Junction Box.jpg|Australian Internal Surface Mounted Junction Box—showing wiring stages.
File:Kuhlo-dosa med Wago.png|Swedish junction box in Kuhlo-style with lever-connector Wago 221, where ground and neutral are connected in common.
Solar panel
{{See also|MC4 connector|Crocodile clip|Solar micro-inverter}}
A PV junction box is attached to the back of the solar panel and it is its output interface.
See also
References
[https://www.psolera.com/en/catalog/enclosures/dry-wall-boxes-blue-range/back-junction-boxes Back Junction Boxes]
External links
{{Commons category | Junction boxes}}
- [http://www.nema.org/ NEMA: National Electrical Manufacturers Association]
- [http://www.ibew.org/ IBEW: International Brotherhood of Electrical Workers]
- [http://www.necanet.org/ NECA: National Electrical Contractors Association]