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.

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 flow (amps)
• \( A \) — Cross-sectional area of conductor (m²)

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

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical equipment receives adequate voltage for proper operation and prevents excessive power loss.

4. Using the Calculator

Tips: Enter the conductor resistivity (default 1.72×10⁻⁸ Ω·m for copper), length in meters, current in amps, and conductor area in m². All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical resistivity for copper?
A: 1.72 × 10⁻⁸ Ω·m for pure copper at 20°C (0.000000000000172 Ω·m).

Q2: Why is conductor length important?
A: Voltage drop increases proportionally with conductor length - longer runs have greater voltage drops.

Q3: How does conductor size affect voltage drop?
A: Larger conductors (greater cross-sectional area) reduce voltage drop for the same current.

Q4: What's an acceptable voltage drop?
A: Typically 3% for branch circuits and 5% for feeder circuits, but check local codes.

Q5: Does this account for temperature effects?
A: No, for precise calculations at different temperatures, adjust the resistivity value accordingly.