Generator Wire Size Calculation

Wire Size Formula:

\[ A_w = \frac{I \times L \times K}{V_{drop} \times \sigma} \]

Current (I):

amps

Length (L):

Factor (K):

Voltage Drop (V_drop):

volts

Conductivity (σ):

Ω⁻¹·mm²/m

Wire Size (A_w):

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1. What is Generator Wire Size Calculation?

Definition: This calculator determines the appropriate wire size (cross-sectional area) needed for generator installations based on current, distance, and acceptable voltage drop.

Purpose: It helps electricians and engineers select the proper wire gauge to ensure safe and efficient power transmission from generators.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ A_w = \frac{I \times L \times K}{V_{drop} \times \sigma} \]

Where:

\( A_w \) — Wire cross-sectional area (mm²)
\( I \) — Current (amps)
\( L \) — Length of wire (ft)
\( K \) — Correction factor (typically 12.9 for single-phase systems)
\( V_{drop} \) — Acceptable voltage drop (volts)
\( \sigma \) — Conductivity of copper (58 Ω⁻¹·mm²/m)

Explanation: The formula calculates the minimum wire size needed to maintain voltage drop within acceptable limits for a given current over a specified distance.

3. Importance of Proper Wire Sizing

Details: Correct wire sizing prevents excessive voltage drop, reduces heat generation, and ensures safe operation of electrical systems. Undersized wires can cause equipment malfunction and fire hazards.

4. Using the Calculator

Tips: Enter the current in amps, wire length in feet, correction factor (default 12.9), acceptable voltage drop (default 3V), and conductivity (default 58 for copper). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical acceptable voltage drop?
A: For most applications, 3% voltage drop is acceptable (3.6V for 120V systems, 6V for 240V systems).

Q2: When would I change the K factor?
A: Use 21.2 for three-phase systems instead of 12.9 for single-phase.

Q3: What conductivity value should I use for aluminum?
A: Use 35 Ω⁻¹·mm²/m for aluminum instead of 58 for copper.

Q4: How do I convert mm² to AWG?
A: Use a wire gauge chart to convert the calculated mm² to standard AWG sizes.

Q5: Does this include safety factors?
A: No, consider adding 25% margin for continuous loads or consult electrical codes.