The XL-21 series distribution box is one of the widely used power control and distribution equipment in low-voltage power distribution systems. Due to its ease of installation, flexibility in use, ease of maintenance, and availability of economical and luxurious models to meet the needs of users. It is used for power distribution, lighting distribution, and power control in power systems with a rated working voltage of 380V, a rated current of 630A and below, and a frequency of 50Hz. The installation method of electrical components is beam type or plate type; the system solution is flexible, easy to install, has strong universality, is easy to maintain and repair.