MCCB,VCB,ACB all are of different type with same 
functioning.
all of them are used to isolate the power or to trip the 
power at the time of fault in line and thus save the 
circuit from further damage and isolate unheathy part from 
healthy one.
if the circuit if of low rating we can go ahead with MCCB 
but for high rating circuit we go for costlier CB that is 
ACB/VCB because they are more reliable and have long life.