Distribution boxes can be broadly categorized by their voltage level, application environment, and primary function. The two most fundamental distinctions are between Low-Voltage Distribution Boards and Medium-Voltage Distribution Enclosures, often referred to as Ring Main Units. The distribution box (DB box) helps safely and efficiently distribute electrical power. Today, electrical systems are essential for homes and industries. It acts as the central point where electricity distribution is managed inside a building. Plus, we'll sprinkle in some practical tips to make sure you're not. 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. Sub Distribution Board (SDB) 3.