The size of a copper busbar is determined by its width, thickness, and length. In general, the larger the busbar, the higher the current it can handle. Here is a Copper Busbar Size Chart to help you choose the right size for your project:

Width (inches) | Thickness (inches) | Length (feet)
-------------------------------------------------------------
1/4 | 1/16 | 10
1/4 | 1/8 | 10
1/2 | 1/16 | 10
1/2 | 1/8 | 10
1/2 | 1/4 | 10
1 | 1/8 | 10
1 | 1/4 | 10
1 | 3/8 | 10
2 | 1/8 | 10
2 | 1/4 | 10
2 | 3/8 | 10
It’s important to note that these sizes are a general guide and may vary depending on the manufacturer. Additionally, the thickness of the copper busbar will affect its ability to dissipate heat, so it’s important to choose the right size for the amount of current being carried.
In conclusion, choosing the right copper busbar size is crucial for the efficiency and safety of your project. Use this size chart as a guide and consult with a professional for further advice.