1. What is a Wire Size Calculator for Voltage Drop?

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 appropriate wire sizes to ensure proper voltage levels at the load.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( A \) — Wire cross-sectional area (m²)
• \( \rho \) — Resistivity of the conductor material (ohm-m)
• \( L \) — Length of the wire (meters)
• \( I \) — Current flowing through the 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 conductor 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: Why is the resistivity value multiplied by 2?
A: The factor of 2 accounts for the round-trip path of current (both the "hot" and "neutral" wires in AC circuits).

Q2: What's a typical resistivity value for copper?
A: Copper has a resistivity of about 1.68×10⁻⁸ ohm-m at 20°C. For aluminum, use 2.65×10⁻⁸ ohm-m.

Q3: What's an acceptable voltage drop?
A: For most applications, 3% voltage drop is the maximum recommended for branch circuits and 5% for feeders.

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: Compare the calculated area with standard wire size tables to select the appropriate gauge.