In this guide, we'll break down the 12 main types of distribution boxes in a way that's easy to understand. Wiring diagram shows both PNP and NPN wiring. Dimensions are shown in mm (in. In the event of an overload or fault, it cuts off power to all linked circuits by disconnecting. In the world of electrical installations, the term DB box —short for Distribution Board box —refers to the central unit that distributes incoming electrical power to multiple outgoing circuits in a building. It improves safety by enabling protection against overload and short circuits, and it improves.