Fuse is mainly used in the circuit, when the circuit appears overcurrent or overvoltage, its own fuse cut off the current, thus playing a role in protecting the safe operation of the circuit, generally the following three factors will have an impact on the life of the fuse.

First: contact parts.

As we know, the fuse belongs to a relatively small device, in the application to the circuit, the fuse contact with the clip, and connect the length of the wire, cross-sectional area. The contact resistance between the fuse box clamps will be too large damage to the fuse life, in the UL standard, the experiment, the fuse and the contact resistance of the clamps should be less than 3 milliohms.

Second: the working environment temperature.

Fuse parameters are in a standard temperature environment, if the working environment is too high will affect the life of the fuse, too low will affect the fuse parameter value changes. Slow-melting fuses such as tin ball type, the temperature at about 160 degrees when the tin began to diffuse to the wire; fast-melting fuses at about 200 degrees when the fusible body began to oxidise more violently. As the fuse oxidises from the outside to the inside, diffuses many times, and is fatigued by thermal stress, the life of the fuse is gradually shortened. Therefore, it is recommended that delayed fuse should not work for a long time in the environment above 150 degrees, and fast blowing fuse should not work for a long time above 175~225℃.

Third: Pulse current.

Fuse in the actual application, many times will meet the pulse current, in did not go through a pulse current, the life of the fuse will be seen, because the pulse impact will produce thermal cycling, which will lead to the diffusion of the fuse, oxidation, thermal stress, etc. produced, and even accelerated. The fuse will become aged with the increase of pulse energy and number of pulses, and the life of the fuse against impact depends on the I2t of the pulse as a percentage of the I2t of the fuse itself.

Through the above introduction, I believe that we have a general understanding of the factors affecting the life of the fuse, so when you buy a fuse, in view of the characteristics of the product use more important is to pay attention to the maintenance of the fuse, so that the life can be longer.