Fuses simply and only work with current (amps). The voltage rating is a maximum mainly due to safety, one would not want to use a fuse rated at 12 volts on a circuit of 120 volts due to safety. A 30 amp fuse rated at 32 volts will work the same as a 30 amp fuse rated at 12 volts with voltages of 12 volts or less.
If a fuse blows it is because the current (amps) exceeded the fuse rating and something to be concerned about.But it could also be a cheap fuse that can not handle it's rated current (or even less) over a sustained period of time.
Note the last sentence, I highlighted it above. Still, it a fuse blows in my car that is a cause for concern.