Circuit Breaker Breaking Capacity Calculator
Estimate required circuit breaker breaking capacity for electrical distribution systems.
Use this breaking capacity calculator to estimate recommended circuit breaker interrupting capacity and short-circuit making capacity based on fault current and engineering safety margin.
Network & Fault Profile
System Characteristics
kA
Recommended Breaker
Standard Rating
Rated Breaking Capacity (Icu / Ics)
31.5
kA
Based on target fault level of 26.4 kA
Dynamic Performance
Peak Duty
Rated Short-Circuit Making Capacity (Icm)
78.75
kAp
Peak current handling ability (~2.5 × Icu multiplier applied)
Selection Guide Notice
This is a preliminary selection guide. True breaker sizing must account for asymmetrical fault currents, system X/R ratios, DC time constants, and specific IEC 60947-2 / IEC 62271-100 testing requirements.
Engineering Reference
Target Calculation
Target kA = Isc × Margin
Peak Making (Icm) Estimate
Icm ≈ 2.5 × Breaking kA
- Icu = Ultimate Breaking Capacity
- Ics = Service Breaking Capacity
- Icm = Making Capacity (Peak)
- Auto-Snap = Selects from standard industry ratings (16, 20, 25, 31.5, 40, 50, 63...)