Intrinsic safety explosion protection
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Does the communication cable that connects intrinsically safe (EXid) devices to non-intrinsically safe devices need to be isolated? Are there any specific regulations in the guidelines?
First of all, there is no intrinsically safe type like EXid; only EXia and EXib exist. In general, intrinsically safe and non-intrinsically safe systems are required to be isolated from each other, but this is difficult to achieve in practical engineering applications. As long as it involves low-voltage systems, it is fine to place intrinsically safe and non-intrinsically safe systems together.
I guess you mean: instruments with an explosion-proof enclosure, equipped with communication ports, where the communication is designed using intrinsically safe signals/circuits. The control room is equipped with a communication safety barrier, allowing the communication cables to be plugged in and removed while the meter is still online ； Without a safety barrier, it is a “non-intrinsic safety circuit”. For the external trough boxes, try to maintain an appropriate distance between intrinsically safe and non-intrinsically safe cables; once they enter the cabinet room, a less stringent approach can be taken – I agree with the view from upstairs. Intrinsic safety systems are very safe, at least in theory, as the standards set are quite stringent.