1. What is Resistance (1-Phase 2-Wire US)?

Resistance in a 1-Phase 2-Wire Underground AC system is defined as the property of the wire or line that opposes the flow of current through it. It depends on the material's resistivity, length of the wire, and cross-sectional area.

2. How Does the Calculator Work?

The calculator uses the resistance formula:

Where:

• \( R \) — Resistance Underground AC (Ω)
• \( \rho \) — Resistivity of the material (Ω·m)
• \( L \) — Length of Underground AC Wire (m)
• \( A \) — Area of Underground AC Wire (m²)

Explanation: The resistance increases with longer wire length and higher resistivity, but decreases with larger cross-sectional area.

3. Importance of Resistance Calculation

Details: Accurate resistance calculation is crucial for determining power losses, voltage drop, and overall efficiency in underground AC power distribution systems.

4. Using the Calculator

Tips: Enter resistivity in Ω·m, length in meters, and area in square meters. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is typical resistivity for copper wire?
A: Copper has a resistivity of approximately 1.68 × 10⁻⁸ Ω·m at 20°C.

Q2: How does temperature affect resistance?
A: Resistance increases with temperature for most conductors due to increased atomic vibrations.

Q3: Why is underground AC resistance important?
A: It helps determine power losses and ensures proper voltage regulation in underground power distribution systems.

Q4: How does wire material affect resistance?
A: Different materials have different resistivity values, with silver having the lowest and nichrome having relatively high resistivity.

Q5: What units should be used for accurate calculations?
A: Use consistent SI units: resistivity in Ω·m, length in meters, and area in square meters for resistance in ohms.