1. What is a DC Cable Voltage Drop Calculator?

Definition: This calculator estimates the voltage drop in a DC electrical cable based on the cable's material, length, current, and cross-sectional area.

Purpose: It helps electrical engineers and technicians ensure proper voltage levels at the load end of DC power systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VD \) — Voltage drop (volts)
• \( \rho \) — Resistivity of conductor material (ohm-m)
• \( L \) — Length of cable (meters)
• \( I \) — Current flowing through cable (amps)
• \( A \) — Cross-sectional area of conductor (m²)

Explanation: The factor of 2 accounts for the round-trip path of current in DC circuits. The formula calculates the voltage lost due to the cable's resistance.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation ensures electrical devices receive adequate voltage to operate correctly and helps prevent energy waste and overheating.

4. Using the Calculator

Tips: Enter the conductor resistivity (default 0.000000000000172 ohm-m for copper), cable length, current, and conductor area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is voltage drop important?
A: Excessive voltage drop can cause equipment to malfunction, reduce efficiency, and potentially create safety hazards.

Q2: What's a typical acceptable voltage drop?
A: Generally, voltage drop should be less than 3% for power circuits and 5% for lighting circuits.

Q3: What resistivity value should I use for copper?
A: Pure copper at 20°C has ρ ≈ 1.72×10⁻⁸ ohm-m (0.000000000000172 ohm-m).

Q4: How does cable length affect voltage drop?
A: Voltage drop increases linearly with cable length - doubling the length doubles the voltage drop.

Q5: What if I know the cable diameter instead of area?
A: Convert diameter to area using A = π × (diameter/2)² before using the calculator.