Quote:
Originally Posted by Jon1967us
@Electronic M, Let me see if I understand that, at 255V we're actually seeing a lower current, normally. At a higher potential, but a lower current, and the fuse cares about current. Once the current reaches .3A
*and if the voltage is at a potential of 125v or higher,*
then it will blow.
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No, the voltage across the fuse will never reach hundreds of volts before it blows. The fuse resistance is a few ohms at most. It blows when the current reaches the rated value, heating the element to the melting point. When the fuse has opened, then it will have across it whatever voltage the circuit produces. The 125 volt rating is only the safe level that the open fuse is guaranteed to block without arcing. (If the fuse is rated for 125 volts AC, then the actual DC or peak AC safe blocking voltage is 1.4x125.)