This guide explores control panels, electrical boxes, breaker panels, bus bars, junction boxes, and custom enclosures to help you understand their sizes, types, and common applications. Used in industrial automation and process control. Houses PLCs, relays, contactors . At its core, a distribution box, also known as a distribution board, panelboard, or fuse box, is a protective enclosure that houses all the electrical components that control and protect the circuits in a building. These two terms are often confused, but they have different functions and uses. What is a Distribution Box? A distribution box, or DB box, is a circuit breaker enclosure.