[Al Skierkiewicz]

You should not be able to prevent a breaker from electrical tripping by holding the handle. This is a saftey feature required on breakers to prevent homeowners from burning their house down by holding a tripping breaker in the "ON" position. It may help with impact tripping but as I remember in our tests it did nothing to prevent trips of any kind. Read the discussion of breaker construction in the robot appendix.
Good Luck