How thick of wire should be used for small busbars

For a small busbar, copper thickness typically ranges from 2 mm to 6 mm depending on current, while aluminum requires a larger cross-section due to lower conductivity.

Key Considerations

Current Carrying Capacity: The thickness of a busbar is primarily determined by the current it must carry. Copper busbars generally support 1.2–1.6 A per mm², while aluminum supports 0.8–1.2 A per mm² under normal air-cooled conditions . For example, a small busbar carrying 50–100 A may require a copper thickness of 2–4 mm, whereas aluminum would need 3–6 mm to safely handle the same current . Material Choice: Copper offers higher conductivity, allowing for thinner busbars, while aluminum is lighter and more economical but requires greater thickness for equivalent performance . Copper is preferred in compact panels or high-efficiency systems, whereas aluminum is suitable for cost-sensitive or open installations . Voltage Drop and Thermal Management: Thicker busbars reduce voltage drop and improve heat dissipation. For small busbars, maintaining a voltage drop below 3% is recommended for stable operation . Proper ventilation and spacing also help prevent overheating. Mechanical Strength: Even for small busbars, sufficient thickness ensures rigidity and durability, especially in systems subject to vibration or movement . Practical Example: A small copper busbar of 50 mm width carrying 100 A might use a thickness of 3–4 mm, while an aluminum busbar of the same width may require 4–6 mm thickness to achieve similar current capacity and thermal performance .

Summary

To select the appropriate thickness for a small busbar:

• Determine the maximum current the busbar will carry.
• Choose the material (copper for higher conductivity, aluminum for cost/weight savings).
• Apply current density guidelines: 1.2–1.6 A/mm² for copper, 0.8–1.2 A/mm² for aluminum.
• Ensure voltage drop and thermal limits are acceptable.
• Adjust thickness for mechanical strength and installation constraints. By following these guidelines, a small busbar can be safely and efficiently designed for your electrical system .