1. What is a Wire Voltage Drop Calculator?

Definition: This calculator estimates the voltage drop in a wire based on its resistivity, length, current, and cross-sectional area.

Purpose: It helps electricians and engineers ensure proper voltage levels in electrical circuits by accounting for wire resistance.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The factor of 2 accounts for the round-trip path in a circuit (both the "hot" and "neutral" wires).

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation ensures electrical devices receive adequate voltage and prevents performance issues or safety hazards.

4. Using the Calculator

Tips: Enter the wire resistivity (default 1.68×10⁻⁸ ohm-m for copper), length in meters, current in amps, and cross-sectional area in m². All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical acceptable voltage drop?
A: For most applications, voltage drop should be less than 3% of the supply voltage for branch circuits and 5% for feeders.

Q2: What's the resistivity of common wire materials?
A: Copper ≈ 1.68×10⁻⁸ ohm-m, Aluminum ≈ 2.65×10⁻⁸ ohm-m at 20°C.

Q3: How does temperature affect the calculation?
A: Resistivity increases with temperature. For precise calculations, use resistivity values at operating temperature.

Q4: How do I convert wire gauge to cross-sectional area?
A: Use our Wire Gauge to Area Converter tool or reference AWG tables.

Q5: Why is the result in scientific notation?
A: Voltage drop values are often very small, so scientific notation provides better precision.