1. What is the Maximum Length Formula?

The Maximum Length formula calculates the maximum cable length based on voltage drop, cross-sectional area, current, and resistivity. It's essential for electrical engineering to ensure proper voltage levels at the end of a cable run.

2. How Does the Calculator Work?

The calculator uses the Maximum Length formula:

Where:

• \( L \) — Maximum cable length (m)
• \( Vd \) — Voltage drop (V)
• \( A \) — Cross-sectional area (mm²)
• \( I \) — Current (A)
• \( \rho \) — Resistivity (Ω·m)

Explanation: The formula calculates how far electricity can travel through a cable while maintaining acceptable voltage levels at the destination.

3. Importance of Maximum Length Calculation

Details: Accurate maximum length calculation is crucial for electrical system design to prevent excessive voltage drop, ensure equipment operates properly, and maintain system efficiency.

4. Using the Calculator

Tips: Enter voltage drop in volts, cross-sectional area in mm², current in amperes, and resistivity in Ω·m. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical resistivity value for copper?
A: Copper has a resistivity of approximately 0.0000000172 Ω·m at 20°C.

Q2: Why is the factor of 2 included in the formula?
A: The factor of 2 accounts for the round trip path of the current (both out and return conductors).

Q3: What is an acceptable voltage drop?
A: Typically, a voltage drop of 3-5% is considered acceptable for most electrical installations.

Q4: Does temperature affect the calculation?
A: Yes, resistivity changes with temperature. The calculation assumes a constant temperature.

Q5: Can this formula be used for both AC and DC systems?
A: This formula is primarily for DC systems. For AC systems, additional factors like power factor and reactance should be considered.