The higher the system voltage applied to the fuse, the more difficult are the internal
arcs to extinguish and the longer the formation of fulgurite that takes place, hence
the relationship between element length and applied system voltage. The formation
of fulgurite sets a fairly close limit on the voltage rating of an HRC fuse. If a fuse
is used within a system having a higher voltage than its rating, there may well be a
failure to interrupt. Although fuses should never be used at voltages greater than their
rating, they can be used at lower voltages.