Calculadora de Carga Elétrica Online Grátis
Total electrical load, recommended breaker size for home appliances
The Electrical Load Calculator totals the wattage of appliances on a circuit or in a property, converts the result to amperage at your supply voltage, and recommends the minimum breaker size to run safely without tripping. Electricians sizing new panels, homeowners adding circuits, and engineers planning building services use it to ensure circuits are neither undersized nor wastefully oversized.
Frequently Asked Questions
Sobre Esta Calculadora
Every electrical circuit has a rated capacity, and the National Electrical Code (NEC) and equivalent standards require that circuits be sized so that the calculated load does not exceed 80% of the breaker rating — the "80% derate rule." Overloading a circuit doesn't just trip the breaker; chronic overloads generate heat in wiring, degrading insulation over time and creating a fire risk.
This calculator adds up the wattage of all appliances on a circuit, converts to amperage at the supply voltage (120 V in North America, 230–240 V in Europe and the UK, 415 V for three-phase), and then applies the 80% derate to give the minimum safe breaker rating. It flags when existing circuits are at or near capacity.
For whole-house load calculations used to size a main service panel, sum all individual circuit loads and apply a demand factor (not all circuits run at full load simultaneously). This tool handles the per-circuit calculation; for panel sizing, work with a licensed electrician who will also account for future load growth and local code requirements.
A Calculadora de Carga Elétrica soma a potência dos aparelhos em um circuito e recomenda o tamanho mínimo do disjuntor.
Fórmula
Total Load (Watts) = Σ(Appliance Wattage × Daily Hours) Amperage = Watts / Voltage
Exemplo Resolvido
Calculating load for a kitchen circuit at 240 V
Entradas:
- Refrigerator: 150 W
- Microwave: 1,200 W
- Dishwasher: 1,800 W
- Electric kettle: 2,000 W
- Supply voltage: 240 V
Passo a Passo:
- Total wattage: 150 + 1,200 + 1,800 + 2,000 = 5,150 W
- Note: kettle and microwave rarely run simultaneously; peak load ≈ 3,950 W
- Peak amperage: 3,950 ÷ 240 = 16.5 A
- Apply 80% NEC derate: required breaker capacity = 16.5 ÷ 0.80 = 20.6 A
- Next standard breaker size: 25 A (or 20 A if staggering appliance use)