240.86 Series Rating Clarification

[anbm]

If panel B is fed out of panel A via a 100A/3P breaker. Panel B has several 20A/1P breakers.
Will this rule apply between 100A /3P breaker in panel A and 20A/1 breakers in panel B?

Or this rule only apply between main breaker and branch breakers of the same panel?

 

[electrofelon]

If panel B is fed out of panel A via a 100A/3P breaker. Panel B has several 20A/1P breakers.
Will this rule apply between 100A /3P breaker in panel A and 20A/1 breakers in panel B?

Or this rule only apply between main breaker and branch breakers of the same panel?

Yes it will apply (assuming there is a series rating, which there likely is if its modern equipment of the same manufacturer). There is no requirement that the two series rated breakers be in the same panel, assembly, or enclosure.

Eaton seems to provide the best descriptions on how to apply series ratings:

http://web.eaton.com/ecm/idcplg?IdcService=GET_FILE&dID=4796305

Look at the first three pages, particularly page 3.