(1) First-level distribution equipment, collectively referred to as power distribution center. They are centrally installed in the enterprise's substation and distribute electrical energy to lower-level distribution equipment in different locations. This level of equipment is close to the step-down transformer, so the electrical parameter requirements are higher and the output circuit capacity is also larger.
(2) Second-level distribution equipment, collectively referred to as power distribution cabinets and motor control centers. Power distribution cabinets are used in situations where the load is relatively dispersed and there are fewer circuits; motor control centers are used in situations where the load is concentrated and there are more circuits. They distribute the electrical energy of a circuit of the upper-level distribution equipment to the nearest load. This level of equipment should provide protection, monitoring and control for the load.
(3) The final-level distribution equipment is collectively referred to as lighting power distribution boxes. They are far away from the power supply center and are dispersed small-capacity distribution equipment.