Why the operation failure of high breaking capacity fuses is so frequent?

Abstract

High breaking capacity (HBC) fuse is today one of the most used low and medium voltage protective devices. Its operation principle presents two singular current values of difficult interruption, "critical current" and "minimum breaking current". These fuses, in general are not able to break any current that begins the melting process. An introduction about the HBC fuse design characteristics and operation modes is given. Standardized fuse classes are discussed based upon the IEC 60269 and IEC 60282 specifications. The error in the selection of the appropriate class is the most common mistake and the consequences go from damages to the protected equipment up to fuse violent explosion. Real typical cases of incorrect selection are presented, pointing out the consequences and risks. It is concluded that the only way to avoid errors in the selection is by means of the deep knowledge of the methodology of application of the HBC fuses.

Temperature Distribution of HBC Fuses with Asymmetric Electric Current Ratios Through Fuselinks

“…Standardised fuse classes are presented in [17] based on the IEC 60269 and IEC 60282 technical standards. The mistake in selecting of the suitable class is the most usual error and the results are faults in the protected equipment up to a severe fuse blast.…”