As Risteard, taking account of any effects of current limiting if applicable.
However for ADS purposes the disconnection time would be 5s, but one would hope that the MCB would operate faster than that!
That's the problem I am having. Based on my readings its 230/0.33=696.96yes, by using 5 secs. from the Zs, calculate the fault current. then go to app.3 and find out the trip time for that MCB at that fault current. then use the If and the t values in the adiabatic.