Explosion-proof sealing issue for excess holes in instrument enclosures
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SH/T 3521-2013 \"Technical Specifications for the Construction of Petrochemical Instrumentation Projects\" 8.8.3 When introducing cables for explosion-proof instruments and electrical equipment, elastic sealing rings should be used to secure them or isolation sealing fillers should be employed for sealing; any excess holes on the enclosure must be made explosion-proof. One hole in the elastic sealing ring should be used to seal one cable. May I ask whether a stainless steel explosion-proof plug is necessary for this explosion-proof seal? Can plastic plugs or plastic caps be used instead? Is there a distinction between intrinsically safe and flameproof types?
In accordance with the requirements of SH/T 3521-2013, when introducing cables for explosion-proof instruments and electrical equipment, any excess holes in the enclosures must be sealed to prevent explosions; however, specific requirements regarding the materials used for such sealing are not clearly specified. Generally speaking, stainless steel explosion-proof plug valves are widely used in explosion-proof devices, and their high-temperature resistance and corrosion resistance endow them with excellent explosion-proof properties. However, plastic wire plugs or plastic plugs can also be used, provided that they undergo appropriate testing and certification to ensure compliance with relevant explosion-proof standards and requirements. As for distinguishing between intrinsically safe and flameproof types, according to the SH/T 3521-2013 standard, the explosion protection rating of instruments can be classified as intrinsically safe (ia category) or flameproof (d category). Depending on the specific circumstances, the appropriate material and type of explosion-proof plug or stopper should be selected, taking into account the equipment’s explosion-proof rating requirements. .
Do plastic plug wires or plastic plugs have explosion-proof properties?
For intrinsically safe equipment, there is no need to worry about whether stainless steel explosion-proof thread plugs are used; in my opinion, explosion-proof types should employ stainless steel explosion-proof thread plugs, and such plugs should also have explosion-proof certification.
Experts say plastic is not explosion-proof, so we replaced all our excess openings with stainless steel plugs.
Plastic should only serve to prevent dust and water from entering; it probably can’t prevent explosions.
In accordance with the requirements for sealing elements specified in 16.4 of GB3836.1-2021, threaded sealing elements shall be sealing elements for Ex equipment, Ex components, or part of the explosion protection certificate for a complete device.
Plastic parts are not only non-explosion-proof but also not waterproof. The plastic plug caps provided with most transmitters and repeaters are threadless; they neither offer protection nor provide explosion-proofing. Theoretically, intrinsically safe instruments do not generate sparks, and this plug can be a threaded plastic plug.