A friend of mine has a (for Austrian measures) ancient breaker panel (supposedly 1961 when everybody else still had Diazed fuses). It has some quirks... there are indivdual breakers for phase and neutral of every circuit... and the breakers more or less refuse to trip!
They're 10 amps H characteristics, meaning the magnetic trip should act extremely fast (H breakers are known to already trip at the startup surge of a modern vacuum cleaner), but iin three out of four dead shorts the 25amps main fuse blew before the breakers even thought of tripping. On Thursday the entire panel has to go.
