1. What is a Voltage Drop Calculator for Constant Current?

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

Purpose: It helps electrical engineers and technicians determine the voltage loss in wires carrying constant current.

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 in both the outgoing and return paths (hence the factor of 2).

3. Importance of Voltage Drop Calculation

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

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 accounts for both the outgoing and return paths in a circuit (round-trip distance).

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: How does temperature affect the calculation?
A: Resistivity increases with temperature. For precise calculations, use ρ values at operating temperature.

Q4: What's an acceptable voltage drop?
A: Typically less than 3% for branch circuits and 5% for feeders, but check local electrical codes.

Q5: How do I convert wire gauge to m²?
A: Use our Wire Gauge Converter tool or reference AWG to mm² conversion tables.