The key differences between the three levels are as follows: 1. Second-level boxes distribute power from the first-level boxes to the point of use. These boxes have inner and outer doors, powder-coated exteriors, and are designed for safety and aesthetic appeal, with rainproof tops for outdoor work. Let's make a hypothesis: a newly built residential area introduces a 10kV incoming line and builds a distribution room. 4kV), power is distributed to a main distribution panel. A tertiary distribution box refers to a switch box, which is responsible for supplying power to only one device. Many feeders leave substation in a concrete ducts and are routed to a nearby pole.