When backfeeding an electrical panel, does a circuit breaker limit power coming in?

Question

I am backfeeding my electrical panel with my generator. I can backfeed it with either a 30amp input (generator one) or 50amp (using generator two). The circuit breaker connected to the generator is on an interlock so for it to be on, the main has to be off so there is no danger.

The circuit breaker in the panel is currently 30amp. Does the breaker limit power going both ways or does it just protect power drawn? Right now, if I am connecting generator two and 50amp, I am removing the 30amp and replacing with 50amp. Do I need to continue to do this? Can I just leave the 50amp in for both generators?

The line connecting where I plug the generator in to the backfeeding breaker is #6/3 so the line can support whatever power I backfeed with.

Answer 1

Assuming you have a 50A inlet you can leave the 50A breaker in place.

Using 60 Hz Alternating Current the electrons change direction 120 times a second, so a circuit breaker normally sees electrons flowing both directions regardless which end of the breaker is connected to line or load.

Answer 2

Presuming the generators each have output breakers, using a 50A breaker for the inlet (with appropriate sized wires, of course) and not changing it should be fine. If you overload the 30A generator, its on-board circuit breaker should protect it.

Or, if you can run all the loads you need to run with the 30A generator and breaker, you can leave it at 30A all the time, and only use 30A of the 50A generator.

The breaker is functional for inlet and outlet - it cares about the number of amps, not the nominal direction of them.