The main parts are the Miniature Circuit Breaker (MCB), Residual Current Device (RCD), busbars, and the main switch. Safe habits and checking the box often help stop electrical accidents. It ensures that electricity flows. What are the functions and uses of DB Boxes? What is a Distribution Box? A distribution box, or DB box, is a circuit breaker enclosure. If you know. Also called a distribution board, panel board, breaker panel, or electric panel, it is the central hub in an electrical system that divides incoming power into various subsidiary circuits. It's where power from the main supply splits into different circuits that feed lights, appliances, and equipment throughout the building.