What is cut-off current?
Current limitation depends on the short-circuit conditions (prospective value, power factor, making angle at the beginning of the short-circuit). Cut-off current characteristics show maximum values of limited current reached in the worse conditions. For a prospective short-circuit current of 10,000 Amp r.m.s. with a totally asymmetrical current, the maximum value could reach 25,000 Amp peak. A 100A gG fuselink limits the first peak to 8,000 Amp, less than the third part of the prospective maximum value. The destructive electrodynamic effects are reduced by 90% (8,000/25,000) 2!
