Regarding the laying of instrument cables, control cables, and communication cables
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This post was last edited by The project’s progress on 2023-10-14 at 22:31. I have a question: when using control cables to transmit communication cables, instrument cables, as well as the DI and DO signals from 380VAc motors or valves, are there any specifications regarding how these cables should be laid within the same tray? Previously, I would separate the DI and DO signal cables for valves and motors from the instrument cables. In Clause 8.3.3 of the Standards for Design of Chemical Plant Piping and Wiring 20512-2014, there is a sentence stating that armored cables and optical fibers do not need to be laid separately. What does this mean? Just to ask further, the chemical industry standards mention instrument AC power cables – can valve control cables with 380V AC be used as a substitute? Since the chemical industry specifications do not mention control cables for high-voltage circuits, does this also apply to the rule in those specifications that armored cables do not need to be laid separately? The power plant specifications state that high-voltage control cables and instrument cables should be laid separately, but they do not specify whether armored cables need to be laid separately as well. Additional note: It is still designed to be installed separately as armored cables
As I understand it, when using control cables for communication cables, instrument cables, control cables, as well as the DI and DO signals of 380V AC motors or valves, a reasonable wiring design should be developed based on the site conditions and installation requirements. There are specific regulations regarding whether cables can be laid in the same tray; it is necessary to refer to relevant industry standards and design requirements, as the demands may vary depending on the industry and application scenario. As mentioned in section 8.3.3 of the Design Specifications for Chemical Plant Piping and Wiring 20512-2014, armored cables and optical fibers do not need to be laid separately; this is likely because the interference between these cables, as well as electromagnetic interference, is relatively low, so it is feasible to lay them together. However, the specific circumstances still need to be considered and evaluated based on the on-site conditions and installation requirements. .
Optical cables (composed of multiple fiber pairs) are generally not affected by electromagnetic interference, while signal copper cables can be affected. I’m not very familiar with the relevant standards, but when I design systems, I make sure to route these two types of cables separately.
I checked the design specifications for power plants, and it states that control cables for high-voltage circuits should be installed separately; currently, it’s the communication cables and instrument cables that are used