1. What is the DC Wire Size Calculation?

The DC wire size calculation determines the minimum cross-sectional area of a wire needed to carry a certain current over a distance while maintaining an acceptable voltage drop. Proper sizing ensures efficient power transmission and prevents overheating.

2. How Does the Calculator Work?

The calculator uses the DC wire size formula:

Where:

• \( A \) — Cross-sectional area (m²)
• \( I \) — Current (A)
• \( L \) — Length of wire (m)
• \( \rho \) — Resistivity of copper (1.68 × 10⁻⁸ Ω·m)
• \( V_{drop} \) — Acceptable voltage drop (V)

Explanation: The formula calculates the minimum wire area needed to keep voltage drop within acceptable limits for a given current and wire length.

3. Importance of Proper Wire Sizing

Details: Correct wire sizing prevents excessive voltage drop (which can affect equipment performance), reduces power loss, and minimizes fire risk from overheating.

4. Using the Calculator

Tips: Enter current in amps, wire length in meters, and maximum acceptable voltage drop in volts. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What resistivity value is used?
A: The calculator uses 1.68 × 10⁻⁸ Ω·m for copper at 20°C. For aluminum, use 2.82 × 10⁻⁸ Ω·m.

Q2: Why multiply by 2 in the formula?
A: The factor of 2 accounts for the round-trip length of the circuit (both positive and negative wires).

Q3: What's a typical acceptable voltage drop?
A: For most DC systems, 3% of system voltage is common (e.g., 0.36V for a 12V system).

Q4: Does this account for temperature effects?
A: No, this uses room temperature resistivity. For high temperature applications, adjust resistivity accordingly.

Q5: How do I convert mm² to AWG?
A: Use a wire gauge table to find the nearest standard AWG size that meets or exceeds your calculated mm² value.