Voltage Drop Formula:
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Definition: This calculator estimates the voltage drop in an electrical wire based on its material properties, length, current, and cross-sectional area.
Purpose: It helps electricians and engineers ensure proper voltage levels throughout electrical circuits.
The calculator uses the formula:
Where:
Explanation: The factor of 2 accounts for the round-trip path of the current (to the load and back).
Details: Proper voltage drop estimation ensures electrical devices receive adequate voltage and prevents excessive power loss in wiring.
Tips: Enter the resistivity (default 1.68×10⁻⁸ ohm-m for copper), wire length in meters, current in amps, and cross-sectional area in m². All values must be > 0.
Q1: Why is resistivity important?
A: Different materials (copper, aluminum, etc.) have different resistivities, affecting how much voltage is lost.
Q2: What's a typical acceptable voltage drop?
A: Generally less than 3% for branch circuits and 5% for feeders, but check local electrical codes.
Q3: How do I find wire cross-sectional area?
A: For round wires: \( A = \pi \times r² \) where r is radius in meters. AWG sizes have standard areas.
Q4: Why does length affect voltage drop?
A: Longer wires have more resistance, causing greater voltage drop for the same current.
Q5: How can I reduce voltage drop?
A: Use shorter runs, larger wire (greater area), or materials with lower resistivity.