Cable Volt Drop Calculator

Voltage Drop Formula:

\[ \text{Voltage Drop} = I \times R \times \text{Length} \times 2 / 1000 \quad \text{(for single phase)} \]

Voltage Drop (V):

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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 of conductors and is an important consideration in electrical system design to ensure proper equipment operation.

2. How Does the Calculator Work?

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

\[ \text{Voltage Drop} = I \times R \times \text{Length} \times 2 / 1000 \]

Where:

\( I \) — Current in amperes (A)
\( R \) — Resistance in ohms per kilometer (ohms/km)
\( \text{Length} \) — Cable length in kilometers (km)
\( 2 \) — Factor accounting for both conductors in single-phase systems
\( 1000 \) — Conversion factor for kilometer to meter

Explanation: The formula calculates the voltage loss along the cable length due to conductor resistance, considering both the outgoing and return paths in single-phase systems.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures that electrical equipment receives adequate voltage for optimal performance. Excessive voltage drop can lead to equipment malfunction, reduced efficiency, and potential safety hazards.

4. Using the Calculator

Tips: Enter current in amperes, cable resistance in ohms per kilometer, and cable length in kilometers. All values must be positive numbers. The calculator provides voltage drop in volts.

5. Frequently Asked Questions (FAQ)

Q1: What is an acceptable voltage drop percentage?
A: Generally, voltage drop should not exceed 3% for branch circuits and 5% for feeder and branch circuits combined, as per electrical codes.

Q2: Why multiply by 2 in single-phase calculations?
A: The factor of 2 accounts for both the hot and neutral conductors in single-phase systems, as current flows through both wires.

Q3: How does cable size affect voltage drop?
A: Larger cable sizes have lower resistance, resulting in less voltage drop for the same current and distance.

Q4: Is this formula applicable to three-phase systems?
A: No, three-phase systems use a different formula: Voltage Drop = √3 × I × R × Length / 1000

Q5: What factors influence cable resistance?
A: Cable resistance depends on material (copper/aluminum), cross-sectional area, temperature, and conductor configuration.