I would like to ask why pressure transmitters have two different explosion-proof temperature groups indicated on them
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As shown in the figure, why are there two different temperature groups for explosion protection indicated as Exd II C T4/T6 on the explosion protection certificate? Shouldn’t T6 cover T4 instead?
. The temperature groups T4/T6 in the label correspond to the equipment protection levels Ga/Gb, respectively. The Ex equipment protection levels Ga/Gb/Gc are the protection levels for Ex equipment used in explosive gas environments other than coal mine gas environments. Under the same conditions, Ga > Gb > Gc. It is marked this way because, first, it indicates that its temperature category can actually reach T6. However, during the authentication process, the two protection levels are processed separately. Different authentication contents cannot be mixed, so they must be marked separately. Second, it indicates that it has not yet reached the level of being able to directly label it as T6 Ga. .
Ga: Equipment for explosive gas environments, with a “very high” protection level, and does not constitute a source of ignition under normal operation, expected failures, or rare failures. Gb: Equipment for explosive gas environments with a “high” protection level, which does not constitute a source of ignition under normal operation or in the event of expected failures. Are you saying that Exd II CT4 Ga and Exd II CT6 Gb are equivalent to the highest level, and cannot both be obtained?
. Yes. It can be used for Exd II CT4 Ga and Exd II CT6 Gb, but not for Exd II CT6 Ga. .
I have another question for the experts: generally, we only consider what explosion protection zone is required, whether it’s for dust or gases, as well as CT4 or CT6. But when do we need to pay attention to Ga and Gb?
GA and GB correspond to which regions respectively?
There are also intrinsically safe versions available for this brand name; everyone might want to give them a consideration. The fact that explosion-proof and intrinsically safe versions coexist does not necessarily mean that it’s fake product
Refer to GB 3836.20-2010 Explosive atmospheres – Part 20: Equipment protection levels (EPL) – Equipment of category Ga