1. What is a Voltage Drop Calculator?

Definition: This calculator estimates the voltage drop in an electrical circuit based on conductor material, length, current, and cross-sectional area.

Purpose: It helps electricians and engineers ensure proper voltage levels throughout electrical installations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

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

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation ensures electrical devices receive adequate voltage for proper operation and prevents excessive power loss.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why is resistivity important?
A: Different materials have different resistivities (copper = 1.68×10⁻⁸, aluminum = 2.65×10⁻⁸ ohm-m), affecting voltage drop.

Q2: What's an acceptable voltage drop?
A: Typically 3% for branch circuits, 5% for feeders, but check local electrical codes.

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

Q4: Why is length doubled in the formula?
A: The formula accounts for the total circuit length (both outgoing and return paths).

Q5: How can I reduce voltage drop?
A: Use shorter runs, larger conductors, higher voltage, or lower current.