The primary roles of a distribution box include: Dividing the main power supply into smaller sub-circuits based on their use. Think of it as the heart of your building's electrical system. Just as a heart receives blood and pumps it to various parts of the body, the distribution box receives the main electrical supply and. This ultimate guide explains what a distribution box does, its internal components, common types, real-world applications, and how to select the right DB Box for your project. We also highlight how reliable manufacturers like NUOMAK support stable, compliant, and cost-effective power distribution. A distribution box, or DB box, is a circuit breaker enclosure. Each outgoing line can be individually.