1. What is Voltage Drop Calculation?

Definition: This calculator estimates the voltage drop in an electrical circuit based on the cable's resistivity, 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 single-phase systems. The formula calculates the voltage lost due to the resistance of the conductor.

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 in cables.

4. Using the Calculator

Tips: Enter the 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 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 3-5% of supply voltage for branch circuits, 1-2% for feeders, but check local codes.

Q3: Does this work for three-phase systems?
A: For balanced three-phase, replace the 2 with √3 (about 1.732).

Q4: How do I find cable cross-sectional area?
A: For round cables: A = π × r² where r is radius in meters, or use manufacturer specifications.

Q5: What affects voltage drop most?
A: Current and cable length have the greatest impact, followed by conductor size and material.