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

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

Purpose: It helps electricians and engineers select appropriate wire sizes to ensure proper voltage levels at load points.

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, round-trip distance)
• \( I \) — 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 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 conductor resistivity (default 1.68×10⁻⁸ ohm-m for copper), wire length (round-trip), current, and maximum allowable voltage drop.

5. Frequently Asked Questions (FAQ)

Q1: Why is the length multiplied by 2 in the formula?
A: The factor of 2 accounts for the round-trip path of current (both hot and neutral wires in single-phase systems).

Q2: 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.

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

Q4: How do I convert m² to AWG or mm²?
A: Use a wire gauge table to find the standard size with area ≥ calculated value.

Q5: Does this account for temperature effects?
A: No, for high-temperature environments, use resistivity values at operating temperature.