Calculadora de Queda de Tensão

The Voltage Drop Calculator is a practical tool for electricians, engineers, and construction professionals. It calculates the voltage loss in a single-phase electrical circuit with copper conductor, using copper resistivity (0.0172 Ω·mm²/m). The calculation considers the electric current (I), conductor length (L), and cross-sectional area (S). This voltage drop is important to ensure equipment operates correctly and to prevent cable overheating.

How it works: simply enter the current in amps, the circuit length in meters, and the conductor cross-section in mm². The formula applied is ΔV = 2 × ρ × L × I / S, where the factor 2 accounts for the round trip of current. The result is the voltage drop in volts. This tool is useful for sizing cables in residential, commercial, and industrial installations, ensuring the voltage at the load point is within acceptable limits (usually below 5% of nominal voltage).

When to use? For example, when designing house wiring, you can check if a 5500 W electric shower (220 V) will have excessive voltage drop if the cable is too long. Or in an industrial warehouse, to size the supply for motors. The calculator helps avoid problems like dim lights, reduced motor torque, or fire risks from wire overheating. Note that the formula is for single-phase circuits; for three-phase, the calculation is different.

Important considerations: copper resistivity varies with temperature (at 75°C it is about 0.0216 Ω·mm²/m). The calculator uses the value at 20°C, which is conservative for normal environments. Also, consider the maximum voltage drop allowed by standard NBR 5410 (usually 5% for branch circuits and 7% for distribution circuits). If the result exceeds these limits, increase the conductor cross-section or reduce circuit length. Always consult an electrical engineer for complex projects.