What should I pay attention to when installing and wiring the distribution cabinet?

The installation and wiring of power distribution cabinet is a work with high technical requirements, and it is necessary to strictly abide by relevant codes and standards to ensure the safe and reliable operation of power distribution cabinet. The following are precautions for installation and wiring of power distribution cabinets:

Preparation before installation

Check the power distribution cabinet: check whether the model and specifications of the power distribution cabinet meet the design requirements, whether the appearance is damaged or deformed, whether the internal electrical components are complete and intact, and whether the connection parts are firm.

Check wiring materials: check whether the specifications and models of wires and cables match the distribution cabinet and load, and whether there are any defects such as damage and fracture. At the same time, prepare the required accessories such as terminals, screws, nuts and washers to ensure their quality.

Tool preparation: Prepare installation tools such as screwdriver, wrench, wire stripper, wire crimper and multimeter, and ensure that the tools are in good condition and function normally.

Installation process

Fixing the power distribution cabinet: according to the design requirements, install the power distribution cabinet in a suitable position to ensure its firm and stable installation, and the verticality and levelness meet the specification requirements. Generally speaking, the verticality deviation of the distribution cabinet should not be greater than 1.5‰, and the levelness deviation should not be greater than 2‰.

Bus bar installation: The bus bar installation shall comply with relevant specifications, and the bus bar shall be connected with special bus bar connecting bolts, which shall be firm, reliable and in good contact. The phase sequence arrangement of bus bars shall comply with the regulations. Generally, facing the distribution cabinet, the phase sequence from left to right or from top to bottom is A, B and C..

Cable laying: Cable laying should be neat and orderly, and avoid crossing and squeezing. The bending radius of the cable should meet the requirements of the specification, generally not less than 10 times of the cable outer diameter. After the cable enters the power distribution cabinet, it should be fixed firmly to avoid shaking.

Wiring operation

Wire connection: The connection between wires and electrical components should adopt appropriate terminals, and the connection should be firm and reliable, and there should be no looseness, virtual connection and other phenomena. When wiring, according to the wiring requirements of electrical components, the wire should be stripped of an appropriate length of insulation, inserted into the terminal, and then pressed with screws or wire clamps.

Grounding connection: the grounding of the distribution cabinet should be reliable, and the grounding bus should be reliably connected with the metal frame and grounding system of the distribution cabinet. Grounding resistance should meet the requirements of the specification, generally not more than 4Ω.

Clear identification: The wires, cables and electrical components in the power distribution cabinet should be marked with corresponding identification, such as phase sequence, loop number and purpose, so as to facilitate future maintenance and overhaul.

Inspection after installation

Wiring inspection: check whether all wiring is correct and firm, and whether there is any missing or wrong connection. Check whether the insulation layer of wires and cables is damaged and whether the terminal is overheated and discolored.

Inspection of electrical components: check whether the actions of electrical components are flexible and reliable, and whether the contact is good. Check whether the coil voltage of relay, contactor and other electrical components is correct and the action is normal.

Insulation test: use an insulation resistance tester to test the insulation resistance of the distribution cabinet, and the insulation resistance should meet the requirements of the specification. Generally speaking, the insulation resistance of the distribution cabinet should not be less than 0.5MΩ.

Electrification test: Conduct electrification test under the condition that the wiring is correct and the insulation is good. Check whether the functions of the power distribution cabinet are normal, whether the instructions of voltmeter, ammeter and other instruments are accurate, and whether the electrical components such as switches and relays are normal.