I think what this thread is saying is that circuit breakers in the US are lower quality than in the UK.
Not sure how you arrive at that conclusion. Certainly they may have slightly different characteristics, but that doesn't make them inferior as you need to take the other ways in which an installation differs into account. You can't condemn every U.S. circuit breaker just because of Federal Pacific!
By the way, terms like RCD, RCBO etc. are not used in the U.S. and will probably confuse the issue here.
