1. What is a Voltage Drop Calculator?

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

Purpose: It helps electricians and engineers ensure proper voltage levels at the load end of electrical circuits.

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 cable (meters)
• \( I \) — Current flowing through cable (amps)
• \( A \) — Cross-sectional area of conductor (m²)

Explanation: The factor of 2 accounts for the return path in DC/single-phase AC circuits. The formula shows how voltage drop increases with length and current, but decreases with larger conductor area.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation 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), cable length, current, and conductor area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is voltage drop important?
A: Excessive voltage drop can cause equipment malfunction, reduced efficiency, and potential safety hazards.

Q2: What's a typical acceptable voltage drop?
A: Generally 3% for feeders and 5% for branch circuits is considered acceptable in most electrical codes.

Q3: What resistivity values should I use?
A: Common values: Copper = 1.68×10⁻⁸ ohm-m, Aluminum = 2.65×10⁻⁸ ohm-m (at 20°C).

Q4: Does this work for three-phase systems?
A: For balanced three-phase systems, replace the 2 with √3 (approximately 1.732).

Q5: How do I convert wire gauge to area?
A: Use our Wire Gauge Calculator or standard AWG tables (e.g., 14 AWG = 2.08 mm²).