Distribution boxes are classified according to the requirements of power supply system:

1. The first level power distribution equipment is called power distribution center. They are centrally installed in the enterprise's substation and distribute power to lower level distribution equipment in different locations. This class of equipment is close to step-down transformer, so the requirements of electrical parameters are high, and the output circuit capacity is also large.

2. Secondary power distribution equipment is the general name of power distribution cabinet and motor control center. The power distribution cabinet is used in the situation where the load is dispersed and the circuit is less; the motor control center is used for the occasion where the load is concentrated and the circuit is more. They distribute the electrical energy of a circuit of the upper power distribution equipment to the nearest load. This equipment shall provide protection, monitoring and control of the load.

3.The final power distribution equipment is called lighting power distribution box. They are scattered small capacity distribution equipment far away from the power supply center