1. What is a Cable 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 electrical engineers and technicians ensure proper voltage levels at the load end of a circuit.

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 single-phase systems. The formula calculates the voltage lost due to the cable's resistance.

3. Importance of Voltage Drop Calculation

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

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why is resistivity important?
A: Different materials (copper, aluminum) have different resistivities, which significantly affect voltage drop.

Q2: What's a typical acceptable voltage drop?
A: Generally, voltage drop should be less than 3% for power circuits and 5% for lighting circuits.

Q3: When would I use this calculator?
A: When designing electrical circuits to ensure proper conductor sizing or verifying existing installations.

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

Q5: How do I convert wire gauge to area?
A: Use our Wire Gauge Calculator or standard tables that list area for each AWG size.