Calculate Voltage Drop Over Distance

Voltage Drop Formula:

\[ Vd = \frac{2 \times L \times I \times \rho}{A} \]

Distance (L):

Current (I):

Resistivity (ρ):

Ω·m

Cross-sectional Area (A):

mm²

Voltage Drop (Vd):

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1. What is Voltage Drop Over Distance?

Voltage drop over distance refers to the reduction in voltage that occurs when electrical current flows through a conductor due to the conductor's resistance. It's an important consideration in electrical system design to ensure proper voltage levels at the load.

2. How Does the Calculator Work?

The calculator uses the voltage drop formula:

\[ Vd = \frac{2 \times L \times I \times \rho}{A} \]

Where:

\( Vd \) — Voltage drop (V)
\( L \) — Distance/length of conductor (m)
\( I \) — Current flowing through conductor (A)
\( \rho \) — Resistivity of conductor material (Ω·m)
\( A \) — Cross-sectional area of conductor (mm²)

Explanation: The formula calculates the voltage loss that occurs due to the resistance of the conductor over a specified distance when carrying a certain current.

3. Importance of Voltage Drop Calculation

Details: Calculating voltage drop is crucial for ensuring electrical equipment receives adequate voltage, preventing performance issues, overheating, and equipment damage. It's essential for proper electrical system design and compliance with electrical codes.

4. Using the Calculator

Tips: Enter distance in meters, current in amperes, resistivity in ohm-meters, and cross-sectional area in square millimeters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is there a factor of 2 in the formula?
A: The factor of 2 accounts for the round trip distance in single-phase AC or DC circuits (both the hot and neutral/return conductors).

Q2: What are typical resistivity values for common conductors?
A: Copper: 1.68×10⁻⁸ Ω·m, Aluminum: 2.82×10⁻⁸ Ω·m at 20°C. Resistivity increases with temperature.

Q3: 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, but local codes may vary.

Q4: How does temperature affect voltage drop calculations?
A: Higher temperatures increase conductor resistance, which increases voltage drop. Calculations should use resistivity values at operating temperature.

Q5: Is this formula applicable to three-phase systems?
A: For balanced three-phase systems, use \( Vd = \frac{\sqrt{3} \times L \times I \times \rho}{A} \) instead of the factor of 2.