Calculadora de Dimensionamiento de Interruptor Gratis
Determina el tamaño correcto de interruptor termomagnético según la carga y el calibre del conductor.
Minimum Breaker Rating
50.0 A
Minimum Breaker Rating vs Full Load Current
Fórmula
## Circuit Breaker Sizing The breaker must protect the cable while allowing normal load current to flow. ### Sizing Rule **Minimum breaker rating = Load current x 1.25** (125% per NEC for continuous loads) Then select the next standard breaker size at or above this value. The breaker rating must also be at or below the cable ampacity to ensure the cable is protected.
Ejemplo Resuelto
A 40 A continuous load with 125% safety factor.
- 01Minimum rating = 40 x 1.25 = 50 A
- 02Standard size = 50 A breaker
- 03Verify that cable ampacity is at least 50 A.
Preguntas Frecuentes
Why 125% for continuous loads?
A continuous load is one expected to run for 3 hours or more. The 125% rule ensures the breaker does not nuisance-trip from sustained loading at its rated capacity, as breakers are tested to carry 100% for limited periods.
What are standard breaker sizes?
Common sizes: 6, 10, 16, 20, 25, 32, 40, 50, 63, 80, 100, 125, 160, 200, 250, 400, 630, 800, 1000, 1250 A. Exact availability varies by manufacturer and region.
How do I coordinate breakers?
The upstream breaker should have a higher rating and slower trip curve than the downstream breaker. This ensures the nearest breaker trips first (selectivity), isolating only the faulted section.
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