XL-21 indoor AC low-voltage power distribution cabinet (box) is suitable for power distribution in power plants and industrial and mining enterprises in three-phase four-wire or three-phase five-wire systems with AC voltage of 500 volts and below. XL-21 low-voltage power distribution box is an indoor device installed against the wall and serviced in front of the screen. The shell is made of bent steel plate and can be used for switching power supply. Different types and current levels of circuit breakers can be used according to the needs of users to meet the needs of different users.