A junction box is an enclosure used to protect and house electrical connections. It secures wiring, prevents accidental contact, and safeguards the connections from dust, moisture, and other environmental factors.

Common types include:

• Standard junction boxes: Used for general wiring connections.
• Weatherproof junction boxes: Designed for outdoor use with protection against rain and moisture.
• Flush-mounted junction boxes: Installed inside walls for a neat finish.
• Surface-mounted junction boxes: Mounted on the surface of walls or ceilings, often used when wiring cannot be hidden.
• Metal junction boxes: Provide additional strength and are often used in commercial or industrial settings.

A junction box is required whenever electrical connections are made outside of a fixture, socket, or switch. It is necessary to contain and protect the connections to meet safety standards.

Junction boxes should remain accessible and should not be buried or covered by drywall, plaster, or other building materials. The cover must be visible and accessible for inspection and maintenance.

In the UK, junction boxes must comply with the BS 7671 wiring regulations. This includes using proper materials, ensuring connections are secure and safe, and keeping the junction box accessible for future inspection and maintenance.