Quote:
Originally Posted by Al Skierkiewicz
Roger,
There is nothing that happens to a breaker that trips for over current that doesn't happen during normal operation.
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Except that you are running several hundred amps through it and it is quite hot, while there is minimal current and temperature increase when you manually trip the breaker via the red button. Pat's suggestion that a phase change in the material takes place (some sort of plastic deformation) seems likely, considering also the difference in temperature and current through the conductive element of the breaker. Perhaps the increase in temperature and current brings the lattice above a threshold energy that allows it to plasticly deform more easily than when the red button is pressed.