Purpose/Aim
Fuses in the high and low voltage range are considered reliable and unobtrusive during their service life. This means that fuses are sometimes used within an application for decades. However, experimental investigations show that fuses are subject to ageing effects.
Experimental/Modeling methods
Given a sample of 280 low-voltage HRC fuse-links and about 35 HV fuse-links plus accessory with a minimum age of 35 years and different application histories, various tests were carried out – primarily according to IEC 60269 and IEC 60282, but also over and above. At this, special attention was spent to fuse applications in 3-phase AC systems, whereas relevant standards usually fit solely single-phase conditions. The experimental tests were supported by the companies KEMA Labs IPH Berlin and other industrial partner.
Results/discussion
By means of examining their thermal behavior, time-current characteristic, cyclic stability and their melting and breaking behavior, deviations from the expected results, i.e. the proper behavior of as-new fuses, were indicate deteriorations. The experimental taken high speed videos show several effects like explosions of “unstressed” fuses due to aging effects.
Conclusions
The experimental results show, that there are several aging effects that are still not under consideration. The actual standards as well as the handling of fuses needs to be reviewed. The includes the testing according actual standards too.
 

multi-factor ageing