Instrument wiring in explosion-proof areas
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If it is in an explosion-proof area and the instrument is equipped with explosion-proof flanges, what other requirements must be met on-site to comply with the standards?
This question is too vague. The instrument itself must be explosion-proof in order to be useful, or it must be intrinsically safe – an intrinsically safe circuit is required.
My requirements here aren’t high; it’s sufficient as long as it reaches SIL2 level
Explosion protection rating and SIL2 are two completely different things
In explosion-proof areas, the use of explosion-proof gland connectors for instrument cable connections indicates discontinuous protection; there are two types of protection: trunking protection and steel pipe protection. In the case of trunking protection, it is also necessary to install cable shielding sleeves at the entrance of the cables into the trunking on site； If steel pipe protection is used, then welding steel pipes, wire protectors, and tee wire passing boxes are also required. For specific details, refer to the chemical industry standard HG/T21581-2012, Automation Installation Atlas (Volume 2), HK105. Furthermore, explosion protection and SIL are two different concepts with no connection between them.