breaking capacity of mccb

From the manufacturer's data sheet.

Simply you can find it from breaker's specifcations tag. However if you want to know about how to find select a breaker for a system regarding breaking capacity, you hsould first calculate prospective short circuit current and then you will select breaker which should have the breaking capacity more than prospective current.

suppose i have generator of 62.5 kva

then breaker current would be = 1.5 x 62.5 = 100 amp

now how could we calculate the breaking capacity of the MCCB

Prospective current can be calculated by total impedence of generator, cable size, length, impedence of terminations and joint.

Suppose prospective current of the circuit upto breaker is 600 Amps. You should choose the breaker of B.C more than 600 Amps. If breaker is not available with this rating, you can use breaker available with minimum B.C (example 5KA).

Can any body let me know exactly how can we select the breaking capacity for the mccb to be used with transformer or gensets .