9 matters needing attention in selecting copper bar of distribution cabinet
Release time:2022-03-31Click:1039
When selecting copper bar, please note:
(1) Generally, the width of copper bar and aluminum bar shall be the same as that of the outlet end of the circuit breaker, and the thickness of the bus can be appropriately reduced at the direct load side to meet the requirements; When the branch bus is connected with the circuit breaker, a round hole is punched on the bus for connection. MNS / GCK branches do not need to do zero line in and out, but must do so.
(2) The zero line row and ground line row in the cabinet are installed in front of or behind the cabinet according to the incoming and outgoing lines; For the convenience of installing the transformer, the copper bar low-voltage metering cabinet shall be disconnected in the metering room and connected with lap blocks. The length of lapping block shall meet the standards of transformer installation and maintenance. For other direct connections, transformers above 4000A shall be fixed with insulated plate bus clamps, and the use of insulators is prohibited.
(3) When the medium and high voltage bus passes through the metal plate, the supporting sleeve shall be provided and other insulation measures shall be taken;
(4) Busbars shall be fixed by insulated supports to ensure a constant distance between busbars and between busbars and other components. The fixed distance between two horizontal fixed points shall not exceed 1000mm, and the fixed distance between two vertical fixed points shall not exceed 800mm. After bending, the copper aluminum bus shall be free of cracks and serious wrinkling. The fold height shall not be greater than 1mm, and the bending radius shall not be less than twice that of the rear row. On the premise of no cracking or serious wrinkling after bending, the copper aluminum bus is allowed to have a bending radius.
(5) The contact surface between copper aluminum bus and electrical components shall be smooth and flat, and the edge and orifice of connector shall be free of burr and unevenness;
(6) The phase sequence and color layout of copper aluminum bus shall be expanded according to the above figure;
(7) There shall be no paint at the bus joint, and the paint interface shall be straight without obvious bending and mismatch. The paint interface of each bus end on the same side of the same component shall be free from obvious irregularity, and the interface difference shall not be 5mm.
(8) The bolt connection and support connection of copper and aluminum bus, the connection between bus and electrical components and the place within 10mm from all connections shall not be painted;
When connecting buses, branch buses and electrical components, the overlapping surface shall meet the following requirements:
1) When connecting copper bar and copper bar, the surface shall be tinned and meet the requirements of customers;
2) When the aluminum strip is connected, it can be connected directly (the oxide layer on the overlapping surface shall be removed).
3) When the copper bar is connected with the aluminum bar, the copper bar shall be tinned or silver plated, and the copper aluminum transition piece shall be used in special cases.
(9) When the bus is overlapped, the contact surface shall be smooth without oxide film, and the cross-sectional area after processing shall meet the following requirements.
1) The copper bar shall not exceed 3% of the original section;
2) The aluminum bar shall not exceed 5% of the original cross section.
Technical requirements for busbar installation:
1) The bus arrangement shall be clear, neat and beautiful, horizontal and vertical.
2) When the copper aluminum bus is connected with the electrical components, a space of no less than 5 mm shall be reserved at the root of the bus and the electrical components.
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