Generator Wire Size Calculator

Generator Wire Size Calculator

NEC 2023 compliant calculations with automatic voltage drop correction

Advanced Generator Wiring Calculator

60°C

NM-B, UF-B

75°C

THW, THWN, SE

90°C

THHN, XHHW-2
Most generators rated for 75°C terminations

Parallel Runs: Allow using smaller wires by splitting current across multiple conductors (NEC 310.10(H)).

Results update automatically as you change values

Calculation Results

Calculations complete! All values meet NEC requirements.
26kW Generator
110A Breaker
Min. Wire Size: #2 AWG Copper
Ground Wire: #10 Copper
Recommended Conduit: 1.5" PVC
Voltage Drop: 2.4%
Parallel Runs: No parallel runs
Current per Conductor: 110A
Max Continuous Load: 88A
Voltage Drop: 2.4% (Max 5%)
1 Set

Note: Calculations comply with NEC 2023 standards including voltage drop limits and parallel conductor requirements.

Calculation Details:

1. Generator: 26kW @ 240V = 108.3A

2. Using breaker size: 110A

3. Wire size: #2 AWG copper (130A @ 75°C)

4. Voltage drop: 2.4% (50ft circuit)

Last updated: Just now

NEC 2023 Standards

Voltage Drop

NEC recommends max 3% voltage drop for branch circuits and 5% for feeders (Art. 215.2).

Parallel Conductors

NEC 310.10(H) allows parallel runs for conductors 1/0 AWG and larger to reduce wire size.

Grounding Requirements

NEC Table 250.122 specifies minimum ground wire sizes based on circuit breaker rating.

Professional Recommendation

For circuits over 150 feet, consider increasing wire size or using parallel runs to maintain voltage drop under 3%. Always consult local electrical codes and a licensed electrician for final installation.

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