What's the difference between relay box and distribution box?

The relay box belongs to the secondary line control box and the distribution box belongs to the primary line power control box.

The primary line power supply refers to the circuit that the grid power supply supplies power to the load through switches or other devices, and the secondary line refers to the control circuit that the grid power supply supplies power to the load through other devices.

In power system, electrical equipment is usually divided into primary equipment and secondary equipment according to its function. Primary equipment refers to electrical equipment directly used to generate, transmit and distribute electric energy, including generators, power transformers, circuit breakers, disconnectors, buses, power cables and transmission lines, and is the main body of the power system. Secondary equipment is low-voltage electrical equipment used to monitor, control, measure, adjust and protect the working state of power system and primary equipment, including measuring instruments, control and operation monitoring signals of primary equipment, automatic monitoring system, relay protection and safety automatic device, communication equipment, etc. The electrical circuit composed of secondary devices connected together according to certain functional requirements is collectively called secondary wiring or secondary circuit, which is an indispensable and important part to ensure the safe production, economic operation and reliable power supply of power system.