Formula and Method
Estimated current = width x thickness x current density x material factor x derating factor.
Assumptions
- Simple cross-section based estimate
- Copper reference unless aluminum is selected
- Temperature rise testing is not included
Important Warnings
- Final busbar rating depends on enclosure, spacing, ventilation, plating, temperature rise, and standard testing.
- Do not use this estimate as a certified rating.
FAQ
Why does enclosure design matter?
The same copper bar can run hotter in a sealed cabinet than in open air. Heat dissipation changes the practical current rating.
Can this size a busbar for short-circuit withstand?
No. Short-circuit thermal and mechanical withstand require separate calculations and tests.