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The formula calculates the length of a wire based on its electrical resistance, cross-sectional area, and material resistivity. This is particularly useful in electrical engineering for determining wire requirements in DC overhead systems with two-wire one conductor earthed configuration.
The calculator uses the formula:
Where:
Explanation: The formula derives from the fundamental relationship between resistance, resistivity, length, and cross-sectional area of a conductor.
Details: Accurate wire length calculation is essential for proper electrical system design, voltage drop calculations, power loss estimation, and material cost optimization in overhead DC transmission systems.
Tips: Enter resistance in Ohms, area in square meters, and resistivity in Ohm-meters. All values must be positive numbers greater than zero for accurate calculation.
Q1: Why is resistivity important in this calculation?
A: Resistivity is a material property that determines how strongly a material opposes electric current flow, making it crucial for accurate length calculation.
Q2: What are typical resistivity values for common conductors?
A: Copper: ~1.68×10⁻⁸ Ω·m, Aluminum: ~2.82×10⁻⁸ Ω·m, Silver: ~1.59×10⁻⁸ Ω·m at 20°C.
Q3: Does temperature affect this calculation?
A: Yes, resistivity changes with temperature. For precise calculations, use resistivity values at the operating temperature.
Q4: What is the significance of the two-wire one conductor earthed configuration?
A: This configuration uses two conductors with one earthed, providing a return path through the ground, which affects system resistance calculations.
Q5: Can this formula be used for AC systems?
A: While the basic principle applies, AC systems require additional considerations for skin effect and proximity effect on resistance.