Transfer Switch Sizing Calculator
Ensure a safe and reliable connection to your home's electrical system by choosing the correct transfer switch size for your generator.
Generator Details
Enter the continuous or "running" wattage of your generator.
Recommended Switch Size
Based on your generator's output of -- Amps.
We recommend the next standard size up to ensure safety and prevent overloading.
Standard Transfer Switch Sizes
Transfer Switch Type Comparison
| Feature | Manual Switch | Automatic (ATS) |
|---|---|---|
| Best Application | Portable Generators | Standby Generators |
| Operation | Must be flipped by hand | Hands-free / Instant |
| Cost | $ (Affordable) | $$$ (Expensive) |
| Installation | Simpler, often sub-panel | Complex, often service entrance |
| Power Management | User manages loads manually | Smart load shedding available |
How Sizing Works
Identify Power
Determine the running watts of your generator. Example: 7,500 Watts.
Calculate Amps
Divide watts by system voltage.
7500W / 240V = 31.25 Amps.
Select Switch
Round up to the nearest standard size. 31.25A -> 50A Switch.
Critical Safety Warning
Installing a transfer switch is NOT a DIY project. It involves working with your home's main electrical panel and can be extremely dangerous if done incorrectly.
Always hire a licensed and insured electrician for transfer switch installation. This ensures the safety of your family, your home, and utility workers.