1. What is a Voltage Drop Wire Size Calculator?

Definition: This calculator determines the minimum wire cross-sectional area needed to limit voltage drop in an electrical circuit.

Purpose: It helps electricians and engineers select proper wire sizes to ensure efficient power delivery and prevent excessive voltage drop.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

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

3. Importance of Proper Wire Sizing

Details: Correct wire sizing prevents excessive voltage drop which can lead to equipment malfunction, reduced efficiency, and potential safety hazards.

4. Using the Calculator

Tips: Enter the 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 resistivity value for copper?
A: Copper has ρ ≈ 1.68×10⁻⁸ ohm-m at 20°C. For aluminum, use 2.65×10⁻⁸ ohm-m.

Q2: Why is there a factor of 2 in the formula?
A: The factor accounts for both the "go" and "return" paths in a circuit (total wire length is 2×L).

Q3: What's an acceptable voltage drop?
A: Typically 3% for branch circuits, 5% for feeders, but check local electrical codes.

Q4: How does temperature affect the calculation?
A: Higher temperatures increase resistivity. For precise calculations, use resistivity values at operating temperature.

Q5: How do I convert the result to AWG or mm²?
A: Use a wire gauge table to find the standard size with area equal to or greater than your calculated value.