1. What is the 400 Amp Wire Size Calculator?

The 400 Amp Wire Size Calculator determines the minimum cross-sectional area of copper wire needed to carry 400 amps of current over a specified distance while maintaining an acceptable voltage drop.

2. How Does the Calculator Work?

The calculator uses the wire size formula:

Where:

• \( A \) — Wire cross-sectional area (mm²)
• \( I \) — Current (400 A fixed)
• \( L \) — Length of wire (meters)
• \( \rho \) — Resistivity of copper (1.68 × 10⁻⁸ Ω·m)
• \( V_{drop} \) — Acceptable voltage drop (volts)

Explanation: The formula calculates the minimum wire size needed to limit voltage drop over a given distance when carrying 400 amps of current.

3. Importance of Proper Wire Sizing

Details: Proper wire sizing is critical for electrical safety, efficiency, and performance. Undersized wires can overheat, cause excessive voltage drop, and potentially create fire hazards.

4. Using the Calculator

Tips: Enter the total length of the wire run (one-way distance multiplied by 2 for round trip) and your acceptable voltage drop. The calculator will determine the minimum wire size in mm².

5. Frequently Asked Questions (FAQ)

Q1: Why is 400 amps a common rating?
A: 400 amp service is commonly used for large residential properties, commercial buildings, and industrial applications with high power demands.

Q2: What's a typical acceptable voltage drop?
A: For most applications, a 3% voltage drop is acceptable. For sensitive equipment, 1% may be required.

Q3: Does this calculator account for temperature?
A: No, this uses standard resistivity values. For high-temperature environments, consult electrical codes.

Q4: Can I use this for aluminum wire?
A: No, this calculator is specifically for copper wire. Aluminum has different resistivity properties.

Q5: How do I convert mm² to AWG?
A: Use an AWG to mm² conversion chart. For example, 107.2 mm² is approximately 2/0 AWG.