Regarding cable laying and local cabinet grounding issues
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There is a clause in HG/t20512 that states, ‘The two wires of the redundant data communication cable should be laid along two different paths.’ What does this mean? Do they not have to be laid in the same location? Also, can the 220Vac power cable that supplies power to the local cabinet and the optical cable share the same tray, with a metal partition added in between? The third question is regarding the grounding of the local cabinets: are two grounding wires to be provided from each cabinet to the nearest electrical grounding plate? There are a large number of local cabinets, distributed across different locations.
1. Redundant data highways shall have separate routing paths with maximum practical physical separation to minimize the possibility of a single event causing the simultaneous failure of both wiring systems. The routing paths for redundant data highways must be approved by the owner. This can be achieved through two different paths, such as one path in each location or different cable trays on either side, providing physical separation between them. 2. Currently, there are no relevant standards specifying whether optical fibers and high-voltage cables can be installed together, but the conventional practice is not to allow such installation. Although optical fibers have high resistance to interference, their mechanical strength is low, which poses significant problems during installation and subsequent maintenance. 3. All cabinets are needed.
I would like to ask: for the 220Vac power cable of the instrument, which is laid in the same tray as the signal cable with shielding, is it still necessary to maintain a certain distance between them by using a partition? How to ensure that there are spacing requirements specified for power cables, and should these be followed?
Isn’t the concern when laying optical cables and power cables together interference? Construction is inconvenient; using cable trays should make installation easier, right?
This post was last edited by GeniusTTUV on 2022-7-4 18:07:1111111
This post was last edited by GeniusTTUV on 2022-7-4 18:08:222222
Well, there’s another question: the separate laying of redundant communication optical cables is done for reliability reasons. I saw this mentioned in chemical industry standards; does it also apply to other industries?
The standards of each industry have their limitations and cannot be applied universally. As specified in the \"Design Code for Detection and Alarm of Flammable and Toxic Gases in Petrochemical Industries\" (GB50493-2019), \"the detection and alarm systems for flammable and toxic gases shall be installed independently.\" However, Document No. 116 issued by the State Administration of Work Safety, titled \"Guiding Opinions of the Supervision Administration on Strengthening the Management of Chemical Process Safety Instrumented Systems,\" includes the GDS system within the category of chemical process safety instrumented systems (SIS systems). At the same time, combustible gas detectors fall under the jurisdiction of fire departments and require CCCF certification.
Optical cables should be laid separately, one by one, in different locations, to minimize the risk of data loss due to mechanical damage