Copper busbars, also known as copper bus, copper busbar, copper busbar, etc., are used as conductive materials in high and low voltage electrical appliances, distribution equipment, bus ducts, distribution cabinets/boxes, etc., playing a role in current transmission and electrical equipment connection in the entire circuit.

## What are the 7 major considerations for selecting copper busbars?

Since copper busbars have this important function, what are the considerations when choosing copper busbars?

- The width of copper and aluminum busbars should be consistent with the width of the circuit breaker appearance end. To meet the relevant requirements, the thickness of copper busbars on the direct load side can be appropriately reduced. Circular holes should be used for connecting the busbars when connecting branch busbars and circuit breakers.
- The installation position of zero busbars and ground busbars in the bus duct should be determined according to the method of incoming and outgoing lines. For convenient installation of transformers, the copper busbars in low-voltage metering cabinets should be disconnected, and splice blocks should be used for connection. The length of the splice block should meet the standard for transformer installation and maintenance, and insulated busbar clamps should be used for fixing for currents above 4000A, and insulators should be prohibited.
- When the medium and high voltage busbars pass through metal plates, matching sleeves should be provided or other insulation measures should be taken.
- Insulated supports should be used for fixing busbars to ensure that the distance between busbars and other components remains unchanged. The distance between two horizontal fixed points should not exceed 1000mm, and the distance between vertical fixed points should not exceed 800mm.
- After bending copper and aluminum busbars, cracks and severe wrinkles should not appear. The height of wrinkles should not be greater than 1mm, and the bending radius should generally not be less than twice the thickness of the busbar after bending. Provided that copper and aluminum busbars do not crack or wrinkle severely, the bending radius is allowed to be equal to the thickness of the busbar.
- The contact surface between copper and aluminum busbars and electrical components should be kept flat and smooth, and there should be no burrs or unevenness at the edges and holes of the connectors.
- At bolt connections and support connections of copper and aluminum busbars, connections between busbars and electrical components, and places within 10mm of all connections, paint should not be applied. The interface requiring painting should be flat without obvious irregularities or bends.

## Two Methods for Calculating Bending Dimensions

After understanding how to choose copper busbars, it’s worthwhile to learn how to measure dimensions when bending copper busbars, primarily through two calculation methods:

### Outer Algorithm for Flat Bends (Right Angle Bends)

Formula for calculating the material length as shown in the diagram: Total length = a + (material thickness) + b + (material thickness) + c + d – coefficient * number of right angle bends

**Note:** When adding material length, it is calculated externally.

**Coefficients are as follows:**

Thickness(mm) | Coefficient | Mold R（mm） |

3 | 5 | 5 |

4 | 7 | 5 |

5 | 9 | 5 |

6 | 10 | 10 |

8 | 15 | 10 |

10 | 18 | 10 |

### Inner Algorithm for Flat Bends (Right Angle Bends)

Coefficients are as follows:

Thickness(mm) | Coefficient | Mold R（mm） |

3 | 0.3 | 5 |

4 | 0.5 | 5 |

5 | 1 | 5 |

6 | 0.5 | 10 |

8 | 1.3 | 10 |

10 | 1.5 | 10 |

### Example

When the material thickness is 3mm, the total length = L + 0.3 + H + 0.3

When the material thickness is 5mm, the total length = L + 1 + H + 1

When the material thickness is 10mm, the total length = L + 1.5 + H + 1.5

Note: Each angle is added twice.

## Conclusion

In conclusion, the selection of copper busbars is crucial in ensuring efficient current transmission and electrical equipment connection throughout the circuit. By adhering to the considerations outlined above, such as maintaining consistent widths, proper insulation, and smooth contact surfaces, users can optimize the performance and safety of their electrical systems. Furthermore, understanding the methods for calculating bending dimensions enhances the precision and reliability of busbar installations. By integrating these guidelines into their practices, professionals can effectively harness the conductivity and versatility of copper busbars for various applications in the electrical industry.