The cable entry device of explosion-proof equipment may experience excessive gaps and fail to explode due to the following situations:

1. The inner diameter of the sealing ring is greater than the outer diameter of the introduced cable by more than 1mm.

2. If the difference between the inner diameter Do of the inlet nozzle and the outer diameter D of the sealing ring exceeds 1.0 (when D ≤ 20mm), 1.5 (when 20<D ≤ 60mm), or 2.0 (when D>60mm).

3. The thickness of the sealing ring is less than 0.7 times the outer diameter of the cable, and the difference in inner and outer diameters of the sealing ring is less than 0.3 times the outer diameter of the cable.

4. The hardness of the sealing ring does not meet the requirement of Shore hardness of 45-55 degrees, and it loses elasticity, deteriorates, and deforms due to aging. The effective size fit gap cannot achieve the sealing effect.

5. Multiple cables are inserted into a single hole of the sealing ring.

6. If the sealing ring is not completely wrapped on the cable sheath or cut open and wrapped on the cable,

7. If there are other wrapping materials between the sealing ring and the cable sheath.

8. The sealing ring is partially damaged.

9. Multiple sealing rings inside one inlet nozzle.

10. Idle inlet nozzles or spare high-voltage junction boxes without sealing baffles or unqualified baffles.

11. The diameter of the baffle is more than 2mm smaller than the inner diameter of the inlet nozzle, and the absolute thickness of the baffle is less than 1.82mm.

The 12 baffle is placed inside the sealing ring, and the pressure plate type inlet or nut inlet metal ring is placed between the baffle and the sealing ring. After tightening the 13 inlet nozzle, there is no margin or the inner edge of the nozzle is not tightly pressed with the sealing ring, or the end face of the sealing ring is not tightly in contact with the device wall, or the sealing ring can move.

14. The pressure plate type inlet nozzle lacks compression bolts or the compression bolts are not tightened.