1. What is a Voltage Drop Cable 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 (Ω·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. The formula shows how voltage drop increases with longer cables, higher currents, and smaller conductors.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical devices receive sufficient voltage to operate correctly and helps prevent energy waste and overheating.

4. Using the Calculator

Tips:

• Enter resistivity (default 1.68×10⁻⁸ Ω·m for copper)
• Specify one-way cable length (not round-trip)
• Enter expected current load
• Provide conductor cross-sectional area

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 branch circuits and 5% for feeder circuits, but check local electrical codes.

Q3: How do I find cable cross-sectional area?
A: For round wires: \( A = \pi \times r² \). Cable specifications often list area in mm² (1 mm² = 1×10⁻⁶ m²).

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

Q5: What resistivity values should I use?
A: Copper: 1.68×10⁻⁸ Ω·m, Aluminum: 2.65×10⁻⁸ Ω·m at 20°C (adjust for temperature if needed).