1. What is a Wire Size Voltage Drop Calculator?

Definition: This calculator determines the required wire cross-sectional area to maintain a specified voltage drop over a given length of wire carrying a certain current.

Purpose: It helps electricians and engineers select the proper wire size to ensure efficient power transmission and prevent excessive voltage drops.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( A \) — Cross-sectional area of wire (m²)
• \( \rho \) — Resistivity of wire material (ohm-m)
• \( L \) — Length of wire (meters)
• \( I \) — Current flowing through wire (amps)
• \( VD \) — Maximum allowable voltage drop (volts)

Explanation: The formula calculates the minimum wire size needed to keep the voltage drop within acceptable limits for a given current over a specified distance.

3. Importance of Voltage Drop Calculation

Details: Proper wire sizing ensures electrical devices receive adequate voltage, prevents overheating, and maintains system efficiency.

4. Using the Calculator

Tips: Enter the wire material resistivity (default 1.68×10⁻⁸ ohm-m for copper), wire length, current, and maximum allowable voltage drop. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical acceptable voltage drop?
A: For most applications, 3% voltage drop is acceptable for branch circuits and 5% for feeder circuits.

Q2: How do I convert the result to AWG or mm²?
A: Use a wire gauge chart to match the calculated area to standard wire sizes.

Q3: Why is resistivity important?
A: Different materials (copper, aluminum) have different resistivities, affecting voltage drop calculations.

Q4: What's the 2 in the formula represent?
A: It accounts for the round-trip path of current (both the "hot" and "neutral" wires).

Q5: How does temperature affect the calculation?
A: Higher temperatures increase resistivity. For precise calculations, use resistivity values at operating temperature.