Hi-Fi Tuning Fuse Holder

     Are components for European style Mains boxes, compatible with those designed for the USA?

                                         I don't believe so.

     The fuse and holder shown are very similar (DIN rail mount/design-wise) to many I've seen, installed in the electronics/power supply panels of newer industrial machines and plating equipment*.

 *ie: https://www.eltron.pl/files/photos/producers/52956cb27a1a0b150eb9dd84faf445d882d7fc26.pdf

            Are HIFI's being distributed, in the US of  A?

https://www.hifi-zubehoer.shop/en/hifi-tuning-sicherungshalter-32a-ohne-sicherung-a-36459.htm

The mechanics of a breaker is shown in this video

The arcing across the breaker points appears to leave significant surface damage .Potentially inhibiting current flow and increasing impedance.If a CB has tripped  a number of times over the life of the unit then this alone could prove detrimental  to audio sonics , making a case for replacement  

Brilliant ! - Love that

Ditto!