Circuit Breaker Size Calculator
Find the correct MCB/fuse rating for your circuit load.
W
PF
Resistive loads (heaters) = 1.0. Motors typically 0.8–0.9.
Recommended Breaker
Formulas
- Load current (A) = Power (W) / (Voltage × PF)
- Design current = Load current × safety factor
- Standard sizes: 6, 10, 16, 20, 25, 32, 40, 50, 63, 80, 100 A
- Select next standard size above design current