If you get a fuse rated for less than 8 amps, you risk the fuse blowing during normal operation. If you get a fuse that is rated too high, you risk damaging the equipment because the fuse will not blow in time.
You can get a 250V or higher rated fuse. This rating should indicate what voltage the fuse can succesfully break. There's no harm in getting a higher rating.
The fuse must also fit what's currently there. There are standard fuse sizes so you should be able to find what you need.