1. What is a Voltage Drop Calculator?

Definition: This calculator estimates the voltage drop in an electrical wire 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 wire material (ohm-m)
• \( L \) — Length of wire (meters)
• \( I \) — Current flowing through wire (amps)
• \( A \) — Cross-sectional area of wire (m²)

Explanation: The factor of 2 accounts for the round-trip path of the current (to the load and back).

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation ensures electrical devices receive adequate voltage and helps prevent power loss and overheating in wires.

4. Using the Calculator

Tips: Enter the wire resistivity (1.68×10⁻⁸ ohm-m for copper), 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 voltage drop important?
A: Excessive voltage drop can cause equipment to malfunction or operate inefficiently.

Q2: What's a typical acceptable voltage drop?
A: Generally less than 3% for branch circuits and 5% for feeders, but check local codes.

Q3: How do I find wire cross-sectional area?
A: For round wires, A = π × r² where r is the radius in meters. AWG sizes have standard areas.

Q4: What's the resistivity of common materials?
A: Copper: 1.68×10⁻⁸ ohm-m, Aluminum: 2.65×10⁻⁸ ohm-m at 20°C.

Q5: Does temperature affect the calculation?
A: Yes, resistivity changes with temperature. For precise calculations, use resistivity at operating temperature.