Bitola mínima fio (aprox)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The minimum wire gauge calculator helps determine the minimum cross-sectional area of an electrical conductor, in square millimeters (mm²), based on the current (A) the circuit needs to support. It uses formulas and technical tables common in electrical engineering, such as the relationship between wire cross-section and current-carrying capacity. For example, a 2.5 mm² wire is suitable for up to 20A, while 6 mm² supports up to 32A.
This tool is essential for electrical projects in homes, commercial spaces, or industries, ensuring selected cables do not overload the system and prevent risks like overheating or short circuits. Note that the presented values are approximations and may vary depending on factors like material type (copper or aluminum), ambient temperature, and distance between the circuit breaker and the device.
To use it, simply input the expected current in the circuit. The calculator returns the recommended minimum gauge to support this load. However, for critical installations or uncertainties, consult a licensed electrician or electronics technician. Safety in electrical installations relies on precise calculations and technical standards like NBR 5410.
Frequently asked questions
Why is it important to choose the correct wire gauge?
The correct gauge ensures the wire can handle the electrical current without overheating, preventing fire risks or equipment damage.
Does the calculator account for factors like distance or material type?
No. It provides approximate values for copper in standard environments. For specific installations, calculations must be adjusted according to technical standards.
Can I use this calculator for direct current (DC) circuits?
Yes, but note that voltage drop over long distances may require larger gauges than the basic calculation suggests.
What if the required current isn't listed in the options?
Choose the next larger gauge immediately above the calculated value to ensure safety and avoid overloading.