1. What is Voltage Drop?

Voltage drop refers to the reduction in voltage in an electrical circuit between the source and load. It occurs due to the resistance in conductors and is an important consideration in electrical system design.

2. How Does the Calculator Work?

The calculator uses the voltage drop formula for single-phase circuits:

Where:

• \( VD \) — Voltage drop (volts)
• \( L \) — Length of the conductor (feet)
• \( R \) — Resistance per 1000 feet (Ω/1000ft)
• \( I \) — Current flowing through the circuit (amps)

Explanation: The factor of 2 accounts for the round trip path of current in a single-phase circuit (both hot and neutral conductors).

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical equipment operates efficiently and prevents issues like dim lighting, motor overheating, and reduced equipment lifespan. Most electrical codes specify maximum allowable voltage drop percentages.

4. Using the Calculator

Tips: Enter conductor length in feet, resistance in ohms per 1000 feet, and current in amps. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is an acceptable voltage drop percentage?
A: Typically, 3% for branch circuits and 5% for feeder circuits is considered acceptable, though local codes may vary.

Q2: How does wire size affect voltage drop?
A: Larger wire sizes have lower resistance, resulting in less voltage drop for the same current and distance.

Q3: Is this formula for AC or DC circuits?
A: This formula works for both AC and DC single-phase circuits, though AC circuits may require additional considerations for power factor.

Q4: Why divide by 1000 in the formula?
A: The division by 1000 converts the resistance from Ω/1000ft to Ω/ft for the calculation.

Q5: How do I account for three-phase systems?
A: For three-phase systems, use \( VD = \sqrt{3} \times L \times R \times I / 1000 \) instead of the factor of 2.