"Just for fun, a Bussmann 7.2kV 25A fuse has a resistance of 0.039 ohms. Take this fuse and misapply it in a 12V application, and the results would be _safe_, but you couldn't really claim that you could ignore the resistance of the fuse *grin* Though this does go back to the original question of applying higher voltage OCPD to lower voltage circuits."
This is why there is a difference between, for example, a 3AG automotive fuse (32v) and a 3AG line-voltage fuse (250v).
Look at the fusible element in an automotive fuse: the element is narrow for a small section, for lower voltage drop.
Conversely, a line-voltage fuse is narrow for the entire length, better suited to break a higher voltage with less arcing.
