[ajross]

The breaker isn't part of the circuit, though. Generator connects to in-wall distribution which connects to appliances. You only go across the circuit breaker on the way to the mains line, which is (hopefully) disconnected. Or else it's not, and indeed you'll get overcurrent protection for any attempt to power your neighbors appliances.

[xani_]

The breaker is the part of the circuit for the other circuits

you'd have something like

    gen -> circuit A -> main bus -> circuit b-> load
                           | 
                        main fuse/switch
                           |
                         outside

So loads on circuit A would not be protected by any fuse but ones at circuit B would.

Also circuit A would allow full generator amps to the devices there, no RCD protection either.

[Dalewyn]

Most houses are wired with master breaker(s) connecting the house to mains lines, and various slave breakers connecting the various lines around the house to the master breaker(s).

If you plug a generator into a wall outlet, that power will pass through the slave breaker protecting that particular circuit as the power flows around to the rest of the house.

[teraflop]

If you make a cable to plug a 15A outlet in your home into a 15A outlet on the generator, then hopefully the generator has its own breaker that would trip if too much current was drawn.

If you plug your house directly into a 40A outlet (which has a different shape) then, yeah, you're screwed.

[kube-system]

If you plug your generator directly into a dryer/oven outlet, it should be on a dedicated branch circuit, and everything else you load in the house will actually have two breakers between it and the generator... one for the branch you're feeding from to the bus, and one from the bus to each branch circuit. And the generator probably has a third.

The only real difference between this setup and a proper generator hookup is a mechanical interlock so that the main and feeder branch breakers can't be on at the same time, and the gender of the generator hookup outlet.