Joe,
The deal is that the "50,000 Amp" short-circuit rating of the breaker does not mean that it will limit the current to 50,000 Amps. Rather, it means that the breaker is designed to reliably open and quench the resulting arc when up to 50,000 amps is flowing through it. If there is more than 50,000 amps, the breaker may fail to open. It might never be able to quench the arc, or it might fuse solid in the closed position, or might fail through any number of other failure mechanisms.
[This message has been edited by SolarPowered (edited 04-17-2006).]
