Electrical Distribution Cabinet

The XL-21 type low-voltage power distribution cabinet is used for power distribution in power plants and industrial/mining enterprises, in three-phase four-wire or three-phase five-wire systems with AC voltage of 500V and below.
The XL-21 type low-voltage power distribution box is an indoor wall-mounted installation type, with front-screen maintenance.

The XL-21 type low-voltage power distribution cabinet is of the enclosed type. The shell is made of bent steel plates. The handle of the knife switch is located at the upper right of the front of the cabinet and can be used as a changeover power supply. A voltmeter is installed on the front panel to indicate the busbar voltage. The front of the power distribution box has a door. When the door is opened, all electrical equipment inside is exposed, facilitating maintenance and repair. This power distribution box adopts a self-designed modular assembly structure, featuring a compact structure, convenient maintenance, and flexible and combinable circuit schemes. In addition to air circuit breakers and fuses for short-circuit protection, it is also equipped with contactors and thermal relays. Operation buttons and indicator lights can be installed on the front door.

Normal Service Conditions
◆ Ambient temperature: -50℃ to +40℃, and the average temperature within 24 hours shall not exceed +36℃.
◆ Altitude: Not exceeding 2000m.
◆ Relative humidity: Not exceeding 50% when the ambient air temperature is +40℃. Higher relative humidity is allowed at lower temperatures (e.g., 90% at +20℃). The possibility of moderate condensation due to temperature changes should be considered.
◆ The inclination of the equipment relative to the vertical plane shall not exceed 5°, and the equipment should be installed in places without severe vibration, impact, or corrosive environments.

Use, Maintenance and Overhaul
Before the power distribution box is put into operation after installation or overhaul, the following inspections and tests must be carried out (for inspections and tests after overhaul, specific items depend on the repair quality):
◆ Check whether the electrical equipment installed inside the power distribution cabinet and the secondary wiring meet the drawing requirements.
◆ Check whether the knife switches and air switches used for operation are flexible and without jamming.
◆ Check whether the contact of the installed electrical equipment is good and meets the service requirements of the equipment itself.
◆ Check whether there are any foreign objects inside the power distribution cabinet and whether all fastening screws are loose.

Outline Installation Dimensions
◆ For the outline and installation dimensions of the power distribution cabinet type A structure, see Figure 1.
◆ For the outline and installation dimensions of the power distribution cabinet type B structure, see Figure 2.

Table 1: Knife-Fuse Combination Switch

Table 2: Current Transformer

Table 3: Fuses

Table 4: AC Contactors

When ordering, the customer should provide the following information:
◆ Single line scheme diagram and single line system diagram;
◆ Expanded secondary circuit system diagram;
◆ Detailed specifications and data of all electrical equipment installed in each box;
◆ When ordering type B structure, the layout diagram and plane layout drawing of the power distribution cabinet must be provided.