Voltage Drop Formula:
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Definition: This calculator estimates the voltage drop in an electrical circuit based on conductor properties and current flow.
Purpose: It helps electrical engineers and technicians ensure proper voltage levels in cable installations.
The calculator uses the formula:
Where:
Explanation: The formula calculates the voltage loss due to conductor resistance over its length.
Details: Proper voltage drop estimation ensures equipment receives adequate voltage and prevents performance issues.
Tips: Enter conductor resistivity (default 1.68×10⁻⁸ ohm-m for copper), length, current, and cross-sectional area. All values must be > 0.
Q1: Why is there a factor of 2 in the formula?
A: The factor accounts for the round-trip path of current (both out and return conductors).
Q2: What's a typical resistivity value for copper?
A: Copper has ρ ≈ 1.68×10⁻⁸ ohm-m at 20°C. For aluminum, use 2.65×10⁻⁸ ohm-m.
Q3: How does temperature affect the calculation?
A: Higher temperatures increase resistivity. For precise calculations, adjust ρ based on operating temperature.
Q4: What's an acceptable voltage drop?
A: Typically 3% for lighting circuits and 5% for other circuits, but check local regulations.
Q5: How do I convert wire gauge to cross-sectional area?
A: Use AWG to mm² conversion tables or our Wire Size Calculator tool.