Yes, there is an article in EC&M Magazine about the very thing Gwz has described?
http://www.ecmweb.com/ar/electric_dont_felled_higher/ This is a quote from the article -
"If the downstream circuit breaker starts opening on a high-current fault within the first half cycle, it may "fool" the upstream, fully rated device into not opening, because the fault current steadily decreases as the downstream contacts open. The result is a downstream device clearing the entire fault, even one well beyond the device's rated interrupting current. The outcome: self-destruction."
Apparently this was not a problem with older breakers that took 2 or 3 cycles to open. Some newer breakers can begin to open in the first half cycle, creating the problem you mentioned.
Re the "turf war". The breaker manufacturers are scrambling to develop ways to cause breaker contacts to open in less than a half-cycle, and thus produce a current limiting circuit breaker. They can see that, with ever higher available fault currents, current limiting fuses/breakers will be the OCPD of choice.
Ed
