What size wire should be used to connect the small busbars

For a small DC busbar, a wire size of approximately 50 mm² (10 mm x 5 mm busbar) is suitable for currents up to 150 A over short distances.

Determining Wire Size

The wire size for a busbar depends on the current it needs to carry, the length of the connection, and the acceptable voltage drop. For small DC busbars, the cross-sectional area of the busbar itself can guide the wire selection. For example, a busbar with dimensions 10 mm thickness × 5 mm width has a cross-sectional area of 50 mm², which is suitable for 150 A over distances up to 5 meters .

Key Considerations

• Current Rating: Ensure the wire can handle the maximum continuous current without overheating. Use the busbar's current capacity as a reference.
• Voltage Drop: Keep voltage drop below recommended limits (typically 2–3% for DC systems) to maintain efficiency .
• Material: Copper wires are preferred for their high conductivity; aluminum can be used but requires a larger cross-section.
• Safety Factor: Include a safety margin (commonly 25%) to account for future load increases .
• Connection Quality: Ensure the wire termination matches the busbar's cross-section to avoid hot spots and excessive resistance .

Practical Example

If your small busbar is 10 mm × 5 mm (50 mm²) and rated for 150 A, the connecting wire should have a similar or slightly larger cross-sectional area to safely carry the current. For copper, this typically corresponds to AWG 1/0 to 2/0 depending on insulation type and installation conditions. Always verify with manufacturer specifications and local electrical codes. By following these guidelines, you ensure that the busbar and wires operate safely, efficiently, and within thermal limits.