XL-21 series power distribution cabinets are suitable for power plants, industrial and mining enterprises,three-phase three wire, three-phase four wire,and three-phase five wire systems with AC voltage of 550V and below,and are widely applicable Used for indoor and outdoor power lighting distribution in industrial and mining enterprises, metallurgical and chemical industries, hotels and banks,stations and docks, rail transit,etc.If used outdoors,please contact the equipment manufacturer Negotiate and resolve.