When selecting copper bar, attention should be paid to:

    (1) Generally, the width of copper and aluminum bars should be the same as that of the outlet end of the circuit breaker, and the thickness of the busbar can be appropriately reduced at the direct load side to meet the requirements; while when the branch bus is connected with the circuit breaker, the bus is punched with a round hole for connection, and the MNS / GCK branch zero bar does not need to be made when entering and leaving from the bottom, but it must be made at the time of upper inlet and outlet.

    (2) The zero bar and ground bar in the cabinet shall be installed in front of or behind the cabinet according to the incoming and outgoing line mode; for the convenience of installing the transformer, the copper bar in the metering room shall be disconnected and connected with overlap block. The length of the overlap block shall meet the standards for the installation and maintenance of the transformer. For other direct connections, the insulation plate bus clamp shall be used for fixing, and the insulator is prohibited.

    (3) When medium and high voltage bus passes through metal plate, matching bushing and other insulation measures shall be provided;

    (4) The bus bar shall be fixed by insulation support to ensure that the distance between the bus bars and other parts remains unchanged. The fixed distance is not more than 1000mm for two horizontal fixed points and 800mm for the vertical two fixed points. The copper and aluminum bus bars shall not have cracks and serious wrinkling after bending. The wrinkle height shall not be greater than 1mm, and the bending radius shall not be less than 2 times of the rear of the busbar On the premise of no cracking and serious wrinkling after bending, the allowable bending radius is equal to the bus thickness;

    (5) The contact surface between copper aluminum bus and electrical components should be smooth and smooth, and the edge and hole of the connector should be prickly and uneven;

    (phase sequence and color arrangement of copper aluminum busbar)

    (6) The phase sequence and color list of copper aluminum bus shall be arranged as shown in the above figure;

    (7) There shall be no paint at the bus connection, and the paint interface shall be straight without obvious bending and worthlessness. There shall be no obvious irregularity in the paint interface of each bus end on the same side of the same component, 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 10 mm from all connections shall not be painted;

    When connecting the bus with the bus, the bus with the branch bus and the electrical components, the lap surface shall meet the following requirements:

    1) When the copper bar is connected with the copper bar, the surface shall be tinned, and the customer's requirements shall be met;

    2) When aluminum bar and aluminum bar are connected, they can be directly connected (oxide layer should be removed from the lap surface).

    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 plate shall be used under special conditions.

    (9) The contact surface of busbar shall be flat and free of oxide film when lapping. After processing, its cross-sectional area reduction value shall meet the following requirements.

    1) The copper bar shall not exceed 3% of the original section;

    2) The aluminum row shall not exceed 5% of the original section.

    Process requirements for bus installation:

    1) The arrangement of bus bars should be clear, neat and beautiful, horizontal and vertical.

    2)  When copper and aluminum buses are connected with electrical components, the root of bus and electrical components shall have an empty position of no less than 5mm (as shown in the figure below).

    (connection diagram of bus bar and electrical components)

    Source: electrical design circle of power experts Union

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