Generally speaking, the distribution boards in the market are basically characterized by small volume, simple installation, special technical performance, fixed location, unique configuration function, no site restrictions, common application, stable and reliable operation, high space utilization, small land occupation and environmental protection effect. It is the control center for commanding various components in the power supply line to reasonably distribute electric energy. It is the control link for reliably receiving the upper power supply and correctly feeding out the load electric energy. It is also the key to obtain the user's satisfaction with the power supply quality. Improve the operation reliability of power distribution board.