Are both the sensors and wires intrinsically safe, and is the junction box explosion-proof? Is that acceptable?
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Dear sea friends: The explosion protection rating of the pressure transmitter is E*aIICT4, the control cable is ZA-ia-DJYPVR32 1*2*1.5 35m, while the junction box comes as a complete set with flameproof sealing connectors, and its explosion protection rating is ExdIICT4. Question: Is it acceptable for the junction box to be explosion-proof (d) rather than intrinsically safe (ia)?
This is equivalent to integrating two types of explosion protection; it’s feasible, but it’s a bit wasteful. Originally, there was no such thing as intrinsic safety for junction boxes; generally, intrinsically safe instruments use flameproof junction boxes.
Hello! I was mistaken, haha. Explosion-proof box JBIS 1-1 1/2'' NPT, 12-3/4'' NPT, 36 terminals, ExeIICT4 enhanced safety rating ； The junction box set comes with flameproof sealed connectors, and the spare port is equipped with an explosion-proof plug; the explosion protection rating is ExdIICT4. Is it true that the explosion-proof box is of increased safety type, while the sealed joints are of flameproof type? Can they be used together?
It is appropriate to choose an increased safety type junction box; if it is to be used for intrinsically safe applications, terminal and other related markings can be in blue... I’m not very familiar with how intrinsically safe certified junction boxes are manufactured
Many flameproof connectors also have intrinsic safety certification; in that case, there’s no problem. It’s simply a waste; it only increases the cost of connectors and the difficulty of installation, without providing any explosion-proofing effect.
What is an intrinsically safe control cable? It’s a concept created by manufacturers
There are still problems with this approach; aside from the increased costs, it does not affect safety or functionality. However, when performing maintenance on signals on site, intrinsically safe signals use blue-sealed connectors that allow for on-site maintenance, whereas explosion-proof connectors prevent such maintenance, leading to confusion.
The method is fine； Operations may mislead others; proper on-site signage is necessary
It depends on which zone the defined area belongs to. In an explosive gas environment, as long as it’s not Zone 0, using explosion-proof or increased-safety designs is sufficient; although using intrinsically safe designs for the instruments is also an option, and raising the requirements is certainly no problem.