Sub-Panel Feeder & Wire Sizing Calculator
Detached garage, workshop, shed, or basement sub-panel installations. Sizes feeder conductor (Copper or Aluminum MHF/SER) for 50A, 60A, 90A, 100A, 125A, 200A sub-panels based on one-way distance to keep voltage drop under 3%.
Step-by-Step Derivation ▼ Show Steps
Calculations adhere to standard electrical engineering physics and National Electrical Code (NFPA 70) regulations.
Engineering Principles & Calculations
This calculator uses the exact mathematical relationships between Sub-Panel Rating (Amps), One-Way Distance (ft), Voltage (120/240V split-phase), Conductor Material (Copper vs Aluminum) to determine Recommended Hot Conductor AWG/kcmil, Neutral AWG, Ground AWG (NEC 250.122), Conduit Size (inches). In practical installations, factors such as ambient raceway temperature, harmonic distortion, duty cycle continuous operation, and conductor impedance must be accounted for by a certified electrician.
Sizes feeder conductor (Copper or Aluminum MHF/SER) for 50A, 60A, 90A, 100A, 125A, 200A sub-panels based on one-way distance to keep voltage drop under 3%.
Typical Application & Industry Guidelines
Detached garage, workshop, shed, or basement sub-panel installations.
Sub-Panel Feeder & Wire Sizing Calculator Benchmark Lookup Table
| Sub-Panel Size | Feeder Material | Up to 75 Feet | 100 - 150 Feet | 150 - 250 Feet |
|---|---|---|---|---|
| 60 Amp Panel | Copper (Cu) | #6 AWG Cu | #4 AWG Cu | #2 AWG Cu |
| 60 Amp Panel | Aluminum (Al) | #4 AWG Al | #2 AWG Al | 1/0 AWG Al |
| 100 Amp Panel | Copper (Cu) | #3 AWG Cu | #1 AWG Cu | 2/0 AWG Cu |
| 100 Amp Panel | Aluminum (Al) | 1/0 AWG Al | 2/0 AWG Al | 4/0 AWG Al |
| 200 Amp Panel | Copper (Cu) | 2/0 AWG Cu | 3/0 AWG Cu | 250 kcmil Cu |
| 200 Amp Panel | Aluminum (Al) | 4/0 AWG Al | 250 kcmil Al | 350 kcmil Al |