1. What is a Voltage Drop Calculator?

Definition: This calculator estimates the voltage drop in an electrical circuit based on conductor properties and current flow.

Purpose: It helps electricians and engineers ensure proper voltage levels in electrical installations by predicting voltage loss.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The formula accounts for both the outgoing and return paths (hence the factor of 2), the conductor's inherent resistance, and the current load.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation 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 Ω·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: Why is there a factor of 2 in the formula?
A: The factor accounts for both the outgoing and return paths in a typical circuit (round-trip distance).

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

Q3: What's an acceptable voltage drop?
A: Most electrical codes recommend less than 3% voltage drop for branch circuits and 5% for feeders.

Q4: How does temperature affect the calculation?
A: Resistivity increases with temperature. For precise calculations, use resistivity values at operating temperature.

Q5: Can I use this for DC and AC circuits?
A: This formula works for DC. For AC, you'd also need to consider power factor and reactance.