From residential 100-amp panels to massive 600 amp main distribution panels in commercial facilities, this comprehensive guide will help you understand distribution board types, sizing calculations, and installation requirements to make informed decisions about your electrical. From residential 100-amp panels to massive 600 amp main distribution panels in commercial facilities, this comprehensive guide will help you understand distribution board types, sizing calculations, and installation requirements to make informed decisions about your electrical. What do the primary, secondary, and tertiary boxes of a distribution box mean? This is a relative issue. Let's make a hypothesis: a newly built residential area introduces a 10kV incoming line and builds a distribution room. The outgoing line from the low-voltage end of the transformer is 0. 4kV to. The three-level distribution system refers to a system that distributes electric power through three levels of distribution devices from the incoming power line at the construction site to the electrical equipment. The physical size, type, and arrangement of major equipment, such as power transformers, power circuit breakers, and switches, may cause variance in the layouts to suit. A distribution box is the heart of any electrical system. Whether in a home or an industrial facility, this box keeps your electrical setup organized, functional, and efficient. When a fault occurs, the circuit.