The distribution cabinet is a general term for the motor control center, which is used in situations where the load is relatively dispersed and the circuit is relatively small. Generally, we see that power distribution cabinets are installed in relatively concealed corners, and the maintenance of low-voltage power distribution cabinets is mainly to ensure the normal and safe operation of low-voltage power distribution cabinets. Annual general physical examination and maintenance of low-voltage distribution cabinets are required. Complete maintenance with the minimum power outage time, generally determining the owner's power outage time in advance.
1、 The content and steps of inspection and maintenance for low-voltage distribution cabinets:
1. Maintenance should start from the low-voltage side of the transformer. After the power is cut off in the distribution cabinet, clean the dust inside the cabinet, check whether the busbar and down lead connections are good, whether the joint points have heat or discoloration, check whether the cable head and wiring pile head are firm and reliable, check whether the grounding wire is rusted, and whether the wiring pile head is tight. All secondary circuit wiring connections are reliable and the insulation meets the requirements.
When checking the drawer type switch, the drawer type switch cabinet should be flexible when pushed in or pulled out, and the mechanical locking should be reliable. Check if the automatic air switch operating mechanism on the drawer cabinet is in place and if the wiring screws are tightened. Clean the dirt on the surface and surroundings of the contactor contact, check if the contact is intact. If the contact is poor, slightly file the contact surface if necessary. If the contact is severely burned (the contact point is worn to 1/3 of the original thickness), the contact should be replaced. The power indicator instrument and indicator light are intact.
3. When repairing the capacitor cabinet, the main switch of the capacitor cabinet should be disconnected first, and the capacitors should be discharged to the ground one by one with a wire of more than 10mm2. The appearance of the shell should be checked and there should be no oil leakage. If the capacitor shell expands, it should be dealt with in a timely manner, and the discharge device, control circuit wiring screws, and grounding device should be replaced. After closing, debug the indication part and automatic compensation part.
4. Maintenance of circuit breakers in the receiving cabinet and contact cabinet: First disconnect all loads, and then use the handle to shake out the circuit breaker. Retighten the wiring screws and check if the elasticity of the blade meets the regulations. Check if the arc extinguishing grid is broken or damaged, manually adjust the mechanical interlocking opening and closing to ensure accuracy, check if the contact is in good condition, if necessary, file the surface of the contact, and check if the internal springs, gaskets, and screws are loose, deformed, or detached.
2、 Maintenance steps for low-voltage distribution cabinets:

1. Before operation, the following steps should be followed: one by one, disconnect the load on the low voltage side, disconnect the circuit breaker on the high voltage side, close the grounding switch, lock the high voltage switchgear, and hang a sign "No Switching On, Someone is Working" on the handle of the switchgear. Then, use a wire of 10mm2 or more to short circuit the busbar and hang the grounding wire, and tighten the busbar screw.
2. Maintenance steps: Clean the contact area of the busbar again, apply power composite grease, tighten with new spring washer screws, check for abnormalities in the insulators and spacing connections between the busbar, and check the reliability of the secondary winding terminal connections of the current, voltage, and transformer.
3. Inspection and testing before power transmission: Remove all grounding wires and short circuits, check if there are any tools left at the work site, confirm that there are no errors, close the isolation switch, disconnect the high-voltage side grounding switch, close the high-voltage side circuit breaker of the operating transformer, remove the signboard, power the transformer, and then close the circuit breaker of the low-voltage side receiving cabinet to power the busbar. Finally, close the associated cabinet and automatic air switches of each branch.
3、 Maintenance precautions for low-voltage distribution cabinets:
1. During the maintenance process, a dedicated person must be assigned to supervise.
2. Electricity must be checked before work.
3. Maintenance personnel should be familiar with and operate the electrical and mechanical interlocking of the entire distribution cabinet.
4. During maintenance, it is necessary to have a detailed understanding of which lines are powered by dual wires.
When repairing the busbar, the residual charges in the circuit should be fully discharged.