Size the transfer switch amperage and wire gauge for your generator (NEC-based).
1 · Your generator
2 · What you need
Code & safety essentials
A transfer switch is required (NEC Article 702) to isolate your home from the utility while on generator power — this prevents lethal "backfeed" onto utility lines. Use a three-position (LINE–OFF–GENERATOR) interlocked switch, never an extension cord into an outlet. The switch amperage must meet or exceed the generator's output and match its largest outlet (a 30A inlet needs a 30A switch; 50A needs 50A).
Educational estimate based on NEC Articles 702, 445, and 310.16 ampacity at 75°C terminations; actual conductor sizing depends on distance (voltage drop), termination ratings, and your transfer equipment's listing. Electrical panel work is hazardous and is regulated — have a licensed electrician perform the installation and pull required permits.