1. What is a Volt Drop in Cable Calculator?

Definition: This calculator estimates the voltage drop in an electrical cable based on the cable's resistivity, length, current, and cross-sectional area.

Purpose: It helps electrical engineers and technicians determine the voltage loss in cables to ensure proper system design and operation.

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 a single-phase system. The formula calculates the voltage drop based on Ohm's Law.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation ensures electrical devices receive adequate voltage, prevents power loss, and maintains system efficiency.

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 cross-sectional 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: Why multiply by 2 in the formula?
A: The factor of 2 accounts for the return path in single-phase AC or DC circuits.

Q3: What's an acceptable voltage drop?
A: Typically less than 3% for branch circuits and 5% for feeders, but check local codes.

Q4: How do I find the cross-sectional area?
A: For round wires: \( A = \pi \times r² \) where r is radius in meters.

Q5: Does this work for three-phase systems?
A: For balanced three-phase systems, replace the 2 with √3 (about 1.732).