Fuse is an electrical component installed in a circuit to ensure the safe operation of the circuit. When a circuit malfunction or abnormality occurs, the current will continue to rise, potentially damaging some of the important devices in the circuit, or possibly burning the circuit or even causing a fire. If the circuit is correctly placed in the fuse, then the fuse will be in the current abnormally high to a certain height and heat, their own melting cut off the current, so as to play a role in protecting the safe operation of the circuit. When we choose a fuse, we often see two different current parameters – rated current and blowing current, what is the difference between them?

1. Rated Current

The rated current, also known as In, of a fuse is determined by the manufacturing department under laboratory conditions. Rated current is to be slightly greater than the normal current, when the fuse or fuse will not heat and can work properly. The normal current value is the value of the current that passes through the fuse during normal operation of the circuit. This parameter is determined by the excitation and load, so it is an important parameter for fuse selection. Current ratings usually include 100mA, 200mA, 630mA, 1A, 2A, 4A, 5A, 6.3A, 10A, 60A, 80A, 125A and so on. The company usually provides the rated current value of various fuses according to the customer’s demand and the actual use of the situation.

2.Breaking Current

Breaking Current is when the circuit current reaches the value of the current, the fuse begins to blow to protect the back end of the circuit current.

The difference between the rated current and the breaking current  of the fuse

Usually, the same fuse rated current is less than the breaking current . The breaking current is twice the rated current. The rated current is the maximum current of a circuit with a fuse. For example, when the maximum current allowed in a circuit is 10 A, a suitable fuse has a current rating of 10 A. The breaking current is the value of current above which the fuse blows to protect the circuit. The corresponding breaking current of fuses with different current ratings may be the same, as can be seen from the parameters in the datasheet. It follows that a fuse should not blow even if the current flowing through it is greater than its rated current but does not exceed the conventional non-blowing current.