Disjuntor padrão (acima I)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
This calculator helps select the appropriate standard circuit breaker based on the desired current rating. By inputting a current value, the tool calculates the next commercial size available (10, 16, 20, 25, 32, 40, 50, 63, 80, 100 A), ensuring the breaker matches the electrical load. It is essential for residential, commercial, and industrial electrical projects.
The formula rounds up the input value to the nearest standard rating, preventing underdimensioning. For example, if the calculated current is 22 A, the recommended breaker is 25 A. This protects circuits from overloads and potential damage.
Use this tool for electrical projects requiring compliance with technical standards like NBR 5410. It is common in lighting circuits, outlets, and specific appliances. Avoid manual adjustments, as they may compromise the system's safety.
Note: The calculator provides a theoretical value. Always consult an electrician or engineer to validate the final design, especially for critical loads or industrial installations.
Frequently asked questions
Why choose the next higher value?
Selecting the next higher value than the calculated current ensures the circuit breaker does not trip frequently due to normal current spikes.
What are the standard circuit breaker values?
Common commercial values are 10, 16, 20, 25, 32, 40, 50, 63, 80, and 100 A, following Brazilian electrical standards.
Can I use this calculator for high-power appliances?
Yes, provided the appliance's calculated current is entered correctly and the circuit is designed to handle the load.
Is there a maximum current limit for this calculator?
The calculation considers up to 100 A. For higher currents, consult a professional and specific standards.
Does this tool replace a full electrical project?
No. It is an initial aid. Complete projects require simulations, voltage drop calculations, and technical validation.