Dust explosion prevention marking -- View the diagram
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Everyone, if it is to be used in a dusty environment and I want to use an intrinsically safe version, how should it be indicated within the red box? Thank you. Expressed as: EX it IIIC T6 Db, is that correct? Especially, I don’t know how to represent the “it” position. Please ask the experts for guidance.
Yes, the notation you mentioned, “EX it IIIC T6 Db”, is correct. Here, “it” refers to intrinsically safe devices and systems, which are those that do not generate sparks or heat sources sufficient to cause an explosion during use. .
One more question: the “tb” model I mentioned should be suitable for use in dusty environments. Under what circumstances is it necessary to use “it”?
In the field of explosion-proof electrical equipment, intrinsically safe devices or systems are used to prevent explosions caused by sparks or heat sources generated during operation. When using explosion-proof electrical equipment or systems in a dusty environment, factors such as the flammability of the dust, its explosion rating, and the operating conditions must be taken into account. If it has been determined that intrinsically safe equipment is required, then both “EX ib” and “EX it” can be used in dust-filled environments. Generally, “EX ib” is suitable for environments with power supplies and circuits that do not rely on a reliable ground connection, including dusty environments ； “EX it” is suitable for power supplies and circuits that do not rely on a reliable ground connection, in situations where it is required that the equipment does not generate sparks or heat sources sufficient to cause an explosion during use, including dust-filled environments as well. However, the specific decision and choice still need to be made based on the actual circumstances. .
ia and ib have different use cases
Thank you all for your replies; GB/T 3836.1 explains things pretty well