This technical paper explains how electrical and test parameters influence the performance and safety margins of low-voltage HRC fuses during breaking-capacity tests (I₁ and I₂) as per IEC 60269-1:2024, Table 21, “Values for breaking-capacity tests on AC fuses”. We prepared this paper to understand why the critical parameters mentioned in Table 21 of IEC 60269-1 are important for HRC fuse breaking-capacity testing. The focus is on understanding how variations in arcing angle, power factor, prospective current, test voltage, and frequency affect critical outcomes such as cut-off current, I²t, arc voltage, arcing time, and failure probability.
 

High Rupturing Capacity (HRC) fuses