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Circuit Breaker Size Calculator helps contractors and tradespeople accurately size, spec, and estimate materials and systems.
Formel
Breaker Size = Load Watts / Voltage × 1.25 (125% NEC rule)
Steg-för-steg-guide
- 1Calculate total load in watts, divide by voltage, multiply by 1.25
- 2Apply the formula using your project measurements
- 3Add required safety factors or waste allowances per code
Lösta exempel
Ingång
2400W load, 120V circuit
Resultat
Breaker = 2400/120 × 1.25 = 25A → use 30A breaker
Vanliga misstag att undvika
- ✕Not applying code-required safety factors or derating
- ✕Forgetting to account for waste and cut losses in material estimates
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