This was proposed by a gentleman named Todd Lottman. Here is a little about Mr. Lottman:
Todd Lottmann is an electrical engineer employed by Cooper Bussmann, Inc. focusing on codes and standards. Todd is an alternate member of NEC Code-Making Panel 12 representing NEMA, a member of the UL 508A standards technical panel, member of NEMA 1IS Industrial Controls section, and involved with the NFPA 79 technical committee. Todd is the Bussmann IAEI representative participating in the national section meetings and various chapter meetings around the country.
No big surprise here.
Don: You were saying that breaekrs ranging from 125 and smaller often overlap in thier trip curves. Often times on a medium sized commercial projects the feeder OCPD feeding the panel that has the BC breakers for the unit equipment are 200, 225 or 400. Would this still create a problem.
And what about series rated systems?
BTW: The proposal can be found here: http://www.nfpa.org/PDF/NECPart4.pdf?src=necdigest