1. What is a Voltage Drop Calculator?

Definition: This calculator estimates the voltage drop in an electrical circuit based on conductor material, length, current, and cross-sectional area.

Purpose: It helps electricians and engineers ensure proper voltage levels throughout electrical installations.

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 conductor (meters)
• \( I \) — Current flowing through conductor (amps)
• \( A \) — Cross-sectional area of conductor (m²)

Explanation: The formula calculates the voltage lost due to the resistance of the conductor over its length.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation ensures electrical devices receive adequate voltage and helps prevent performance issues or equipment damage.

4. Using the Calculator

Tips: Enter the conductor resistivity (default 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 there a factor of 2 in the formula?
A: The factor of 2 accounts for the round-trip path of current (out to the load and back).

Q2: What's a typical resistivity value for copper?
A: Copper has ρ ≈ 1.68×10⁻⁸ ohm-m at 20°C. For aluminum, use 2.65×10⁻⁸ ohm-m.

Q3: What's an acceptable voltage drop?
A: Generally, voltage drop should be less than 3% for branch circuits and 5% for feeders.

Q4: How does temperature affect the calculation?
A: Higher temperatures increase resistivity. For precise calculations, adjust ρ for operating temperature.

Q5: Can I use this for AC circuits?
A: This provides a basic estimate. For AC circuits, additional factors like power factor and reactance should be considered.