Lemon HiFi-Tuning Fuse?

There are/is a thread on this issue with the recommendation of using a rating above the replaced original. 

I read a post saying that, I should be fine with the HiFi Tuning 500v rating over the original 250v rating because the current rating is the same. The fuse is a fast blow version, so the same as the original.
Kenny

A fast blow fuse as a AC mains fuse feeding a presumably linear power supply (Transformer/ Diode Bridge/ Capacitor) is highly unlikely,  much more common is a slow blow for this application, your original fuse will have some letter stamped into the end cap identifying if its a slow blow or a fast blow.

Good Listening

Peter

Kenny, Noromance may be referring to the ongoing "Synergistic Red Fuse" thread, in which several people reported experiencing false blows (fuses blowing unnecessarily) with some SR fuses in some equipment. I and others therefore suggested using SR fuses having a current rating one or possibly two rating increments higher than the current rating of the stock fuse. I have no idea as to whether or not that may be applicable in the case of HiFi Tuning fuses.

The voltage rating difference you referred to is a different matter. And everything else being equal a rating of 500V is actually better than a rating of 250V, although as a practical matter it is unlikely to make any difference in a 120V application. The significance of the voltage rating is that when the fuse **should** blow if that rating is lower than the applied voltage the fuse might not open the circuit properly (i.e., it might continue to conduct current). Or it might rupture or explode.

Also, the only time a fuse will "see" those kinds of high voltages will be when a mains fuse (or a fuse that is in some other high voltage circuit) has blown or is in the process of blowing. Under normal operating conditions the voltage between the two terminals of a fuse will be a small fraction of a volt, regardless of the voltage that is applied to the circuit.

Regards,
-- Al