Inrush Current

The relevant one here is the 800A magnetic trip, which might occur if a number of inductive loads (motors, transformers) are energized all at once.

The 40kA pertains to the ability of the MCCB to interrupt large short-circuit or ground-fault currents.

You should seek competent help since you do not know.

Consulting CR4 might conceivably be a step in that very direction, if only the competent/incompetent ratio were higher.

Perhaps. That's one of the pitfalls of an anonymous open forum.

I'm confident that the competence/incompetence ratio of members is still much higher than that of the questioners.

Seeking free anonymous help is a sure sign of desperation, or unwillingness to spend a buck.

moodu, engaluku therium

What's going price (you had to pay) for the link to CR4? Is CR4 advertised as a "Place to Go for All Your Homework Assignments Answers"? Does your school offer Research 101?

The important thing is that the breaker is there to protect the CABLE.

Please note the below,

1) magnetic tripping is for short circuit where the minimum is 800A (if it is not adjustable) without time delay

2) 40kA is the withstanding capacity of the mccb for a maximum short circuit current for a type tested time limit

4) Inrush current will come to picture if the connected loads are inductive only, so calculate the inductive loads connected and its starting current.

5) from the question itself clear that u r away from the subjects so conduct a relay co-ordination study (discrimination study) by an expert to avoid such a nuisance tripping,