Also, from the risk assessment (lots of what I do in my day job) protection is only good if easy to use and doesn't result in the user bypassing it.
Example- fuses- relatively cheap, but if a user keeps blowing a fuse over and over, they tend to put in a higher rating to keep it from blowing.
Breakers- manual reset is best, but for the same reasons, users either cannot figure out why they don't have track power or eventually complain and bypass. Thus self resetting is a compromise. You still have protection, less than manual reset, but less anger from the user.
Again, for the purist- a super fast instant trip manual reset breaker is the safest. However, imagine a club layout, or novice user needing to know each and every time to reset the breaker.
