Maximum Cable Length Voltage Drop Calculator

Maximum Cable Length Formula:

\[ L_{max} = \frac{VD_{max} \times A}{2 \times \rho \times I} \]

Maximum Voltage Drop:

volts

Cable Cross-Sectional Area:

m²

Material Resistivity:

ohm-m

Current:

amps

Maximum Cable Length (m):

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1. What is a Maximum Cable Length Voltage Drop Calculator?

Definition: This calculator determines the maximum length a cable can be run without exceeding the allowable voltage drop, based on cable properties and current.

Purpose: It helps electrical engineers and technicians design efficient electrical systems by preventing excessive voltage drops in cables.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ L_{max} = \frac{VD_{max} \times A}{2 \times \rho \times I} \]

Where:

\( L_{max} \) — Maximum cable length (meters)
\( VD_{max} \) — Maximum allowable voltage drop (volts)
\( A \) — Cross-sectional area of the cable (m²)
\( \rho \) — Resistivity of the conductor material (ohm-m)
\( I \) — Current flowing through the cable (amps)

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

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical devices receive adequate voltage, prevents power loss, and maintains system efficiency.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why is the resistivity value important?
A: Different materials have different resistivities (copper vs aluminum), which significantly affect voltage drop calculations.

Q2: What's a typical maximum voltage drop?
A: For most applications, 3% of supply voltage is recommended (e.g., 3.6V for 120V systems).

Q3: Why is the formula multiplied by 2?
A: The factor of 2 accounts for the round-trip path of current (out to load and back to source).

Q4: How do I convert cable size from AWG to m²?
A: Use AWG to mm² conversion tables, then convert mm² to m² by dividing by 1,000,000.

Q5: Does this account for temperature effects?
A: No, for high-temperature environments, use adjusted resistivity values.