When current between the conventional non-fusing current and the rated breaking capacity (current) specified by related standards acts on a surface-mounted fuse, the fuse immediately responds and poses no risk to the surrounding environment. The expected fault current for the circuit in which the surface-mounted fuse is installed must be less than the rated breaking capacity current specified by the standards. Otherwise, when a fault occurs, the fuse may experience continuous arcing, ignition, leading to the fuse being burnt, melting together with other components, and the fuse markings on the circuit board becoming unreadable. Of course, even if the fuse has a breaking capacity that does not meet safety regulations, using it can still result in the aforementioned hazards.

Therefore, engineers must always prioritize choosing high-quality fuses. High-quality fuses are produced, tested, and quality-controlled strictly according to safety regulations. High-quality surface mount fuses, of course, are more costly than those of lower quality, but they ensure that our entire system will not fail to break when needed, thus providing genuine circuit protection and preventing any potential danger.

Let's take a look at the voltage drop of the fuse again.

The voltage drop of a fuse refers to the voltage drop across the fuse terminals under rated current conditions. It reflects the internal resistance of the fuse, which should not be too high. Installing a fuse with an excessively high internal resistance (voltage drop) in a circuit will affect the circuit's system parameters, causing the circuit to malfunction. The standard not only specifies an upper limit for the voltage drop value but also regulates its consistency.