⚡ CircuitSecrets
Breaker & Cable Selection Calculator
Professional circuit breaker sizing from cable size — or cable size from required current. PVC, NYY, IYAL cable types with full reference table.
PVC 450/750V
NYY 600/1000V
IYAL 250/440V
Size → Breaker
Current → Size
Standard MCB Sizes
Protection Sizing
Cable & Breaker Input
Calculation Mode
Size → Breaker
Current → Size
Cable Type
PVC 450/750V — Single Core (Cu)
PVC
NYY 600/1000V — Single Core
NYY-1C
NYY 600/1000V — Three Core
NYY-3C
NYY 600/1000V — Four Core
NYY-4C
IYAL 250/440V — Single Core (Al)
IYAL
Cable Size — click or type
Protection Result
Breaker & Cable
— mm²
▶
—
MCB/MCCB
▶
Load
Breaker Size
—
Amperes — MCB
Nearby Standard Sizes
Full Rating Table
| Size (mm²) | Rating (A) | Std Breaker (A) | Status |
|---|
► Selection Method
Cable-Breaker Selection Rule
IEC 60364-4-43: I_B ≤ I_n ≤ I_z
I_B: Design current of circuit
I_n: Breaker rated current
I_z: Cable current-carrying capacity
Rule: Breaker ≤ Cable rating (protect cable)
NEC 240.4: Add 25% safety for motors
⚠ Note: Ratings based on standard reference conditions. Apply derating for ambient temperature, grouping and installation method. Always verify with local electrical codes (IEC 60364 / NEC / BNBC).
