Common explosion-proof safety hazards of equipment in explosive hazard areas

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Below, we will introduce some common explosion-proof safety hazards associated with equipment in explosive environments, as well as solutions to address them. 　　I. Equipment Selection ； 　　II. Product Quality ； 　　III. Equipment Installation ； 　　IV. Electrical wiring installation ； 　　V. Grounding and equipotential bonding issues ； 　　VI. Inspection, maintenance, etc. I. Explosion-proof safety hazards in equipment selection 1. Use of ordinary electrical products in areas at risk of explosion. 　　2. Use electrical equipment designed for use in coal mines in factory premises. 　　3. Use explosion-proof electrical equipment designed for gas-filled environments in explosive dust environments. 　　4. From the perspective of its external structure, it appears to be an explosion-proof product. However, these products have neither product nameplates nor explosion-proof markings or product certification information (such as the explosion-proof certification number). Products that lack the necessary certifications for explosion protection, and at the same time cannot provide such certificates. 　　5. From the perspective of its external structure, it appears to be an explosion-proof product. However, among the brand names of these products, there is only the generic “EX” mark and the explosion-proof symbol, but no product certification information (such as the explosion-proof certificate number). It is not possible to verify whether this product has been tested and certified by an **authorized testing institution. 　　6. Fake and substandard products that are classified as ordinary products by professional inspectors, yet are labeled with explosion-proof markings. 　　7. In hazardous areas containing Class IIC substances, use Class IIB explosion-proof products. 　　8. The equipment selection requirement is a T4 temperature category, but explosion-proof products of the T1 temperature category were actually used. II. Safety hazards exist in explosion-proof electrical products themselves 1. The casing of explosion-proof electrical products is damaged. 　　2. The nameplates of explosion-proof electrical products are missing or unclear. 　　3. The isolation and sealing filler between the flameproof chamber and the wiring chamber of the explosion-proof and enhanced safety composite products does not meet the requirements. III. Explosion-proof safety hazards in the installation of electrical equipment 1. The introduction of cables does not meet the requirements. 　　2. Excess inlet holes are sealed with clay/plastic sealing elements/unssealed. 　　3. The fastening bolts are inconsistent: missing, loose, corroded, lacking springs, or lacking flat washers. 　　4. The cable or wire entry point of the flameproof electrical equipment is directly connected to the steel pipe. 　　5. The flexible tube is connected directly to the equipment, with no cable entry device installed. 　　6. The cable entry device used for installing flameproof equipment does not match that of explosion-proof equipment. 　　7. The gap at the flameproof joint of the flameproof equipment is too large. 　　8. Rust on the flameproof joint surface. 　　9. An coating is applied or a gasket is used at the flameproof joint surface between the cover and the box body. 　　10. The independent explosion-proof chambers are interconnected, with no isolation or sealing measures in place. 　　11. The distance between the flameproof joint surface and solid obstacles is too small. 　　12. Aging of the housing or the sealing gaskets leads to increased gaps, resulting in a protection level that does not meet the requirements and allowing water to enter inside. 　　13. Approved safety-enhanced equipment had electrical components replaced or added without authorization. 　　14. The bending degree of the explosion-proof flexible tube is too low; the flexible tube is aged, and the rubber coating is damaged. IV. Problems in the laying of cable lines 1. Cable deformation and damage. 　　2. Cables are connected directly in hazardous areas. 　　3. The wires are twisted together within the increased-safety wiring. 　　4. Connect the wires inside the wire gland. 　　5. No isolation and sealing measures were taken when the cable passed through different areas. 　　6. The armored cable is not equipped with an armored cable entry device. 　　7. The armor layer of the armored cable is exposed. 　　8. Idle cable ends are disposed of in hazardous areas, and excess bare copper wires, without being secured or insulated, are placed arbitrarily inside intrinsically safe junction boxes. V. Grounding and equipotential bonding issues 1. External grounding is not connected. 　　2. Issues related to the series connection of external grounding wires, as well as the equipotential bonding of cable trays and liquid conveyance pipelines. 　　3. The external grounding wire is less than 4mm2. 　　4. The external grounding bolt is corroded. VI. Inspection and Maintenance 1. Inspection and Maintenance of Explosion-Proof Electrical Equipment For explosion-proof electrical equipment in use, a system of daily inspection and maintenance as well as regular professional testing and inspections should be implemented. The issues reflected in the typical cases cited in the appeal are all key points for routine inspection and maintenance, and the details will not be repeated here. 　　During inspection and maintenance, when it is found that the explosion-proof electrical equipment has seen a decline in its explosion-proof properties or has become ineffective due to factors such as external damage, atmospheric corrosion, chemical corrosion, mechanical wear, or natural aging. It should be overhauled. The maintenance of explosion-proof electrical equipment shall be carried out in accordance with GB3836.13-2013. If, after maintenance, the original level of explosion-proof performance cannot be restored, it may be handled in accordance with the following principles based on its actual technical performance: a) use it at a lower explosion-proof rating; b) use it as a non-explosion-proof electrical device. 　　2. Failure of the explosion-proof properties of explosion-proof electrical equipment: If, during maintenance, it is found that the structure or parameters of such equipment have changed, resulting in them no longer conforming to the original explosion-proof classification and design, and if these issues cannot be resolved, then it is considered that the equipment has failed, and it must be stopped from use immediately and replaced. For example: a) The enclosure of an explosion-proof electrical device is severely deformed and cannot be repaired ； 　　b. The flameproof surface is severely damaged and cannot be repaired ； 　　c. The flame arrestor gap exceeds the **standard and cannot be restored ； 　　d. Cracks in the enclosure of explosion-proof electrical equipment that do not meet the original explosion-proof requirements.