What is different between CB utilization category A & B? How to select? Any criteria?

[ElecEE8]

As per below statement:
"Circuit breakers shall have utilization category A, except for circuit breakers feeding sub-distribution switchboards and require selectivity by means of an intentional time delay shall have utilization category B"

Why normally CB utilization shall be Cat. A and for feeding sub-distribution shall be Cat. B.
What is different?
Please help to clarify this.

 

[ScottyUK]

Oh, the magic of Google. Here's what Schneider have to say about it, plus an extract from IEC 947-2.

https://www.schneider-electric.co.in/en/faqs/FA12108/

 

[Hoxton]

If this is an extract from a client specification, then it is poorly written in my view. It should at least contain the words “in accordance with IEC 60947-2.”

 

[ElecEE8]

@ScottyUK - Thanks a lot!

@Hoxton - Yes, it is extracted from specification of one of client. The words as you mentioned were there in the spec.

For protection coordination, I just think another way around, like use CB Cat. B for Incomer/Bus-tie as well and only for outgoing feeders that use Cat. A.
Can we?