What is a Distribution Box? A distribution box, or DB box, is a circuit breaker enclosure. It is a vital part and central hub of any electrical system. The hub distributes electrical power from a single input source to various circuits throughout a building. Its primary function is to organize incoming power into subsidiary circuits, each safeguarded by a fuse. A distribution box, also known as a power distribution box or electrical distribution box, is used to distribute electrical power safely to multiple circuits. Concealed Installation: These boxes are.