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What are the installation precautions for low voltage switchgears?
Feb 09, 2017

 

Installation precautions of low voltage power distribution cabinet

 

The installation location of low voltage power distribution switchboard should be free from sunlight, water, moisture and there is enough operation space in the front. Clean the equipment inside the cabinet, check if connecting terminals, switches, contactors are well and if there is overheating inside at fixed time. And check the seal performance of power distribution switchgear at fixed time to prevent small animals from entering and prevent dewing. For the damp areas, moisture eliminator and dryers are needed. Check the installation position is tight, no deviation and shaking.

Requirements for equipment

a. Check the appearance of the cabinet has no damage or deformation and the painting is complete. Internal checking: electrical device, elements, insulation porcelain parts are complete, no damage and cracks.

b. Verify the code(serial number) of cabinet is consistent with the installation location and check the cabinet number, circuit number according to design drawings. The grounding of cabinet door should soft copper braided wire and specialized connecting terminals. Wiring inside the cabinet is in order, meeting the requirements of design and acceptance regulations.

Working condition

Internal painting of civil engineering for installation place has been finished, doors and windows are installed. Embedded pipes and embedded elements are cleaned and transportation conditions are met and road is clear.

Power distribution cabinet locating

Verify the location of cabinet according to the site requirements and installation conditions. Elastic location is used according to the dimensions of cabinets.

Installation of basic steel frame

a. Prefabricate and process basic steel frame based on the drawings and proceed antiseptic treatment. Put the basic steel frames on the reserved iron pieces according to the marked position on the construction drawings. After levelness and alignment, weld basic steel frame, embedded iron pieces, washer. The top of the steel frame should be 10mm more than the ground.

b. Basic steel frame ground: after install the frame, weld grounding lines to the two ends of frame, face of weld should be twice of the width of flat steel and connect with the cabinet grounding blocks. Antiseptic treatment should be made.

Installation of low voltage electrical control cabinets

1. Cabinet installation: Layout according to construction drawings and locate the power distribution cabinets on the foundation steels one by one according to the order. For single cabinets, use pad irons which should be less than three for the vertical degree regulation of cabinet and side and weld to tight. For cabinets in parallel, regulate the levelness and cabinet deviation to meet the requirements of construction specifications.

2. Wall hung type cabinets can be fixed on the wall by expansion bolts. Embed fishtail bolts on hollow bricks or concrete block wall or fix split bolts.

3. Embed bushing box to install cabinet and the rear panel should be level with the wall.

4. After regulation, fix the cabinet and foundation steels with bolts.

5. Cabinet grounding: Every cabinet should connect with foundation steel separately, use copper wire to connect PE blocks with grounding bolts and use spring washer to prevent loosening. Use cooper braided wire to connect the door with PE blocks.

6. Connection between the top of cabinet and busbar: use busbar combination wrench to fix and apply neutral vaseline on the contact surface. When connect the busbar among the cabinets, pay attention to the distance between busbar and other elements or shell not too close and the phase position is right.

7. Control circuit check: check if the lines are loosed due to transportation, if loosed, tight one by one and check if the electrical elements are damaged. The control circuits of cabinets are calibrated before factory delivery, personal adjustment are not permitted, if there is problem, contact supplier.

8. After calibration of wiring, make every core to circle and connect to terminal plated by galvanized screw, flat washer and spring washer. Every side of terminal plate presses one line, less than two and add flat washer between the two lines. Tin coating should be applied for strand wires, no breaking strand.