Maximum Cable Length Calculator

Cable Length Formula:

\[ L = \frac{V_d \times A}{I \times \rho} \]

Allowable Voltage Drop:

Cross-sectional Area:

m²

Current:

Resistivity:

Ω·m

Maximum Cable Length (m):

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1. What is a Maximum Cable Length Calculator?

Definition: This calculator determines the maximum length a cable can be run while maintaining acceptable voltage drop levels.

Purpose: It helps electricians and engineers design electrical systems with proper voltage regulation.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ L = \frac{V_d \times A}{I \times \rho} \]

Where:

\( L \) — Maximum cable length (meters)
\( V_d \) — Allowable voltage drop (volts)
\( A \) — Cross-sectional area (square meters)
\( I \) — Current (amperes)
\( \rho \) — Resistivity (ohm-meters)

Explanation: The formula calculates how far current can travel through a conductor before the voltage drop exceeds the specified limit.

3. Importance of Cable Length Calculation

Details: Proper cable length calculation ensures electrical devices receive adequate voltage and prevents excessive power loss in wiring.

4. Using the Calculator

Tips: Enter the allowable voltage drop, cable cross-sectional area, current, and resistivity (default 1.68×10⁻⁸ Ω·m for copper). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical allowable voltage drop?
A: For most applications, 3% of the supply voltage is acceptable (e.g., 3.6V for 120V systems).

Q2: How do I convert wire gauge to cross-sectional area?
A: Use AWG to mm² conversion tables. For example, 12 AWG ≈ 3.31 mm² ≈ 3.31×10⁻⁶ m².

Q3: What resistivity value should I use?
A: 1.68×10⁻⁸ Ω·m for copper, 2.82×10⁻⁸ Ω·m for aluminum at 20°C.

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

Q5: Should I include safety factors?
A: Yes, consider reducing the calculated length by 10-20% for safety margins.