One-line diagram builder
Permit offices often ask for a one-line diagram. Pick the setup closest to yours, fill in the ratings, and get a labelled diagram with the backup breaker and feeder wire size worked out. It runs in your browser; nothing is stored or sent.
Maths: 2023 NEC 240.6(A), Table 310.16, 310.15(B)(1), 110.14(C). Always use an interlock or transfer switch; never a double-ended cord.