How to Select Distribution Box Fuse

2019-03-19 11:16:41

General Principles for Selection of Fuses for Distribution Box


(1) Determine the type of fuse according to the operating conditions.


(2) When choosing fuse specifications, melt specifications should be chosen first, and then fuse specifications should be selected according to melt.


(3) The protection characteristics of fuses should cooperate with the overload characteristics of the protected objects.


(4) In the distribution system, fuses at all levels should match each other. Generally, the rated current of the upper melt is 2-3 times higher than that of the next melt.


(5) As for the fuse used to protect the motor, attention should be paid to the influence of the starting current of the motor. The fuse is generally used only as the short circuit protection of the motor, and the thermal relay should be used for overload protection.


(6) The rated current of the fuse shall not be less than the rated current of the melt; the rated interruption shall be greater than the maximum short circuit current that may appear in the circuit.