1. What is Voltage Drop in Wires?

Definition: Voltage drop is the reduction in voltage in an electrical circuit caused by the resistance of the conductors.

Purpose: This calculator helps electricians and engineers determine how much voltage is lost between the power source and the load.

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 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 calculation ensures electrical devices receive adequate voltage to operate correctly and prevents energy waste.

4. Using the Calculator

Tips: Enter the wire resistivity (default 1.68×10⁻⁸ ohm-m for copper), length, current, and cross-sectional area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is voltage drop important?
A: Excessive voltage drop can cause equipment malfunction, overheating, and energy inefficiency.

Q2: What's a typical acceptable voltage drop?
A: For most applications, voltage drop should be less than 3% for branch circuits and 5% for feeder circuits.

Q3: What resistivity value should I use?
A: Use 1.68×10⁻⁸ for copper or 2.65×10⁻⁸ for aluminum at 20°C. Adjust for temperature if needed.

Q4: Why multiply by 2 in the formula?
A: The factor of 2 accounts for both the "hot" and "neutral" (or positive and negative) conductors in the circuit.

Q5: How do I reduce voltage drop?
A: Use shorter wire runs, larger wire gauge (increased area), or materials with lower resistivity.