1. What is a Voltage Drop Calculator (120V)?

Definition: This calculator estimates the voltage drop in a 120V electrical circuit based on conductor properties and current.

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

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VD \) — Voltage drop (volts)
• \( \rho \) — Resistivity of conductor material (Ω·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 conductors over their length.

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 Ω·m for copper), length, current, and cross-sectional area. 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 "hot" and "neutral" conductors in a 120V circuit.

Q2: What's a typical acceptable voltage drop?
A: Generally, voltage drop should be less than 3% for branch circuits (3.6V for 120V systems).

Q3: How do I convert wire gauge to cross-sectional area?
A: Use standard AWG tables or our Wire Size Calculator tool.

Q4: What resistivity value should I use for aluminum?
A: Use 2.65×10⁻⁸ Ω·m for aluminum conductors.

Q5: Does this include temperature effects?
A: No, this is for standard conditions (20°C). For higher temperatures, adjust resistivity accordingly.