Busbar Current Rating & Ampacity Calculator
COMPUTE COPPER & ALUMINUM BUSBAR AMPACITY, CROSS-SECTION & TEMPERATURE RISEBusbar Ampacity Results
Busbar Calculation Formulas & DIN Standard
I_max = k × A^0.62 × ΔT^0.5 (DIN 43671 / DIN 43670)
Copper and aluminum rectangular busbars are widely used in low-voltage switchboards and MCC panels. Parallel bars increase current capacity, but proximity and skin effect factors apply for multiple bars.
Frequently Asked Questions
What is DIN 43671 / DIN 43670 standard?
DIN 43671 specifies current carrying capacity for copper busbars, while DIN 43670 covers aluminum busbars under standard ambient temperature (35°C) and target temperature rise (30°C to 50°C).
Why is Copper preferred over Aluminum for busbars?
Copper has higher electrical conductivity (approx. 58 MS/m vs 36 MS/m for Al), smaller required cross-section for the same current, higher mechanical strength, and better resistance to contact oxidation.
How does putting multiple bars in parallel affect total current rating?
Adding parallel busbars (e.g. 2 or 3 bars per phase) increases total current capacity, but not linearly due to reduced cooling surface and mutual magnetic induction. Two bars typically give ~1.6x to 1.8x the rating of a single bar.