An Electric junction box is an enclosure of two or more wires carrying an electrical current that protects electrical connections, maintains solid connections and provide a safety barrier to prevent fires.
Electric junction boxes are majorly recommended as it is not feasible to run a wire from every outlet or switch back to the main service panel as placing so many wires at one place can be difficult and dangerous. Junction boxes have made this task easy and also has reduced the risk that comes with the use of excessive wiring. Another benefit of electric junction boxes is that it becomes easy to detect and repair any electrical problem in a building as junction boxes are protective, easy to find and easily accessible.
Electric junction boxes are either made up of metal or plastic and come in various shapes like they can be round, square or octagonal and sizes that can be used for different purposes. An electric junction box is constructed by keeping a few things in mind like there has to be a box for receiving and connecting electrical conductors, a mounting flange connected to the box, attachment of box to an exterior layer with a round hole of construction panel, mounting clips on flange which are shaped to extend through the thickness of exterior layer of construction panel.
There is a variety of purposes for which different junction boxes are used. Some junction boxes are simply used to protect the connection of multiple wires and have a flat plate covering it while some electric junction boxes are used for wall switches, some are used for hanging ceiling fixtures and some electric junction boxes are made for retrofit work while some are specifically made for new construction. Various types of electric junction boxes that can be used for domestic purposes are round pan metal electrical box, round pan plastic electrical box, Octagon metal electrical box, Octagon plastic electrical box, Ceiling fan-rated metal electrical box, ceiling fan-rated plastic electrical box and 4-inch square box.
In a building, some electrical connections are made without the protective box i.e. junction box like in hidden ceiling, attic locations or inside wall cavities. But these junctions are not safe or reliable and can arise future problems so it is recommended that every building, house or home should use an electric junction box for safe and reliable electrical connections.