1. For fuses with jaws, the fuse tube should be tightly inserted into the jaws.
2. The fuse equipped with an action indicator should be easy to check the action of the indicator.
3. The organic insulator of the melting tube of the drop-out fuse should have no cracks or deformations; the angle between the axis of the melting tube and the plumb line should be 15° to 30°, and its rotating part should be flexible; it should not touch other parts when falling objects and damage the fusion tube.
4. The specifications of the fuse wire should meet the design requirements, and there is no bending, flattening or damage. The melt and the tail wire should be crimped tightly and firmly.