Main features:
The XL-21 type low-voltage power cabinet is suitable for use in power plants and industrial and mining enterprises. It is applicable to three-phase three-wire, three-phase four-wire, and three-phase five-wire systems with an AC voltage of 500V or below, and is used for power and lighting distribution. 
The XL-21 type low-voltage power cabinet is an indoor device that is installed against the wall and is accessible for maintenance from in front of the panel.

Normal operating environmental conditions:
Ambient temperature: -5°C to +40°C, with the average temperature within 24 hours not exceeding +36°C;
Altitude: Not exceeding 2000m;
Relative humidity: Not exceeding 50% when the ambient air humidity is +40°C; can have a higher relative humidity at lower humidity levels (+20°C is 90%); considering temperature changes, moderate frosting is allowed;
The inclination angle of equipment installation relative to the vertical plane should not exceed 5°;

the equipment should be installed in a place without severe vibration, impact and corrosion. 

Structural features:
The XL(F)-21 type low-voltage power distribution cabinet is an indoor wall-mounted, single-front door distribution device. Its basic structure is made by bending steel plates and welding angle steel. On the right side of the front, a knife switch operation handle can be installed for power cut-off and connection operations. On the box cover, operation buttons, indicator lights and display instruments can be installed. After opening the box, all the internal equipment of the distribution cabinet is exposed, which is convenient for maintenance and repair. This distribution cabinet is equipped with an air circuit breaker, fuses as short-circuit protection, and also has contactors and thermal relays. Both the door and the shell are welded with grounding screws to ensure a reliable connection between the shell and the ground.