What is the principle for determining the rated current of fuse melts?

Different types of fuses have different protection characteristics. Generally speaking, we consider it only as protection against short circuits or continuous overloads. The determination principle of the rated current of the fuse melt is mainly based on the load capacity and properties.

1. For loads such as transformers, electric furnaces, and lighting, the rated current of the melt should be slightly greater than or equal to the load current.
2. For power transmission and distribution lines, the rated current of the melt should be slightly less than or equal to the safe current of the line.

3. For motor loads, due to the high starting current, it is generally possible to follow the selection of (1.5-2.5) times the rated current.

4. For short-circuit protection of multiple motor loads, the rated current of the melt is greater than or equal to (1.5-2.5) times the maximum motor rated current, plus the calculated load current of other motors.