Signal classification in instrument wiring boxes
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When designing instruments, should the signal type be taken into consideration for the instrument circuits in an instrument junction box? For example, intrinsically safe signals and non-intrinsically safe circuits need to be separated.
Intrinsic safety signals and non-intrinsic safety circuits should be separated; it is advisable to install separate wiring boxes for intrinsic safety signals and those for non-intrinsic safety circuits.
Separate them. For example, those that require 220V power supply need to be separated from 4–20mA signals; three-wire heating resistors and combustible gas detectors also generally have their own wiring boxes
Intrinsic safety vs. non-intrinsic safety, with a separation for those connected to SIS and those not connected to SIS, as well as a separation between 220V and 24V