1. What is a Metric Voltage Drop Calculator?

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

Purpose: It helps electricians and engineers ensure proper voltage levels in electrical installations using metric units.

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 drop for a round-trip circuit (hence the factor of 2).

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation ensures electrical devices receive adequate voltage and prevents performance issues or safety hazards.

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 resistivity important?
A: Different materials (copper, aluminum) have different resistivity values that significantly affect voltage drop.

Q2: What's the factor of 2 in the formula?
A: It accounts for both the outgoing and return paths in a typical circuit.

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

Q4: How do I find conductor area?
A: For round wires: \( A = \pi \times r^2 \) where r is radius in meters.

Q5: Does this work for AC and DC circuits?
A: This formula is primarily for DC. For AC, additional factors like power factor must be considered.