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 DC or single-phase AC circuits.

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.

4. Using the Calculator

Tips: Enter the resistivity (default 0.000000000000172 ohm-m for copper), cable length, current, and cross-sectional area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is resistivity important?
A: Different materials have different resistivities (copper = 1.72×10⁻⁸ Ω·m, aluminum = 2.65×10⁻⁸ Ω·m) which affect voltage drop.

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

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

Q4: How do I find cable cross-sectional area?
A: For round conductors, A = π × r² where r is the radius in meters.

Q5: What about temperature effects?
A: Resistivity increases with temperature. For precise calculations, use resistivity values at operating temperature.