XL-21型动力配电柜应用于民用建筑中作为交流频率50HZ，电压500V及以下三相五线电力系统的动力配电和照明配电用。 XL-21型动力配电柜系户内封闭式，箱体由异形钢管及薄钢板组装而成，其正面为单扇左开门，门上装有电压表，电流表和操作电器，信号电器。刀开关操作手柄装在箱前右柱上部。箱体上部有可拆卸的盖板，箱内右侧设有固定电缆之线夹。配电箱靠墙安装，进出线电缆由底部引入。用户有要求。亦可在箱顶、盖顶上开进线敲落孔或加装母线室。
XL-21 distribution box．with frequency of 50HZ(AC)，rated voltage 500V，is used in motive power distribution and light—ing distribution of industrial and civilian buildings in the grid of three phases and five lines
XL-21 power distribution box should be installed indoors close，the body of the box is composed of abnormal shape steel pipes and thin steel boards，Its face is a one—way door drawn to the left hand．On the door，there are voltage meters，current meters and electrical apparatus of signals，Knife switch is installed up on the pole in the front of the box，there is a lid that is movable on the top of the box．On the right side in the box，there are clamps fixating cables．The box should be installed against the wall．Input lines and output lines should all run via the bottom of the box．If the users have special request，we can drill the box top and lid or set a busbar compartment．
