1. What is Three Phase Voltage Drop?

Definition: Voltage drop is the reduction in voltage in an electrical circuit between the source and load due to conductor resistance.

Purpose: Calculating voltage drop helps ensure proper equipment operation and compliance with electrical codes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VD \) — Voltage drop (volts)
• \( I \) — Current (amperes)
• \( L \) — Length of conductor (meters)
• \( R \) — Resistance per unit length (ohms/meter)

Explanation: The √3 factor accounts for the phase difference in three-phase systems. Voltage drop increases with current, conductor length, and resistance.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures:

• Electrical equipment receives adequate voltage
• Compliance with electrical codes (typically 3-5% max drop)
• Efficient system design and energy savings
• Prevention of equipment malfunction

4. Using the Calculator

Tips: Enter the current in amps, conductor length in meters, and resistance in ohms/meter (default 0.0001 Ω/m for copper). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the acceptable voltage drop percentage?
A: Typically 3% for branch circuits and 5% for feeder circuits, but check local codes.

Q2: How do I find conductor resistance?
A: Resistance tables provide Ω/m values based on conductor material and size.

Q3: Does this account for power factor?
A: This simplified formula assumes unity power factor. For precise calculations, include reactance.

Q4: Why is three-phase different from single-phase?
A: Three-phase uses √3 (1.732) factor due to 120° phase separation between conductors.

Q5: How can I reduce voltage drop?
A: Use larger conductors, reduce circuit length, or decrease load current.