What are the requirements for cable shaft design according to the specifications regarding direct burial of control cables?
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The control cables are fitted with protective sleeves and laid underground at intervals of 400 meters. Are there any requirements regarding cable trenches? What are the relevant specification references?
This post was last edited by waneng on 2017-11-9 08:49 at http://bbs.hcbbs.com/thread-1770398-1-1.html
They are all instrument selection documents; there is no information on cable laying.
Code for Construction and Quality Acceptance of Automated Instrumentation Projects
I checked the \"GB 50168-2006 Code for Construction and Acceptance of Cable Lines\", but there are no instructions regarding cable trenches for directly buried cables.
The HG_T20512-2014 regulations for the design of instrument piping and wiring contain only the following provisions; there is no mention of cable trenches: 8.6 Direct burial installation of cables 8.6.1 When there are few, scattered instrument testing points in outdoor installations and no pipe racks available, it is advisable to use armored cables for direct burial, while taking anti-corrosion measures. 8.6.2 When directly-buried cables pass through roads, they should be protected by protective pipes. The cover depth of soil above the pipe should not be less than 1000 mm. 8.6.3 The burial depth of directly buried cables shall not be less than 700 mm; in permafrost areas, they should be buried below the permafrost layer. When deep burial is not possible, measures should be in place to prevent damage to the cables. 8.6.4 The minimum clear distance between directly buried cables and the underground foundation of buildings is 600 mm, and the minimum clear distance from them to power cables shall comply with the provisions in Table 8.1.9 of these specifications. 8.6.5 Direct-buried cables shall not be laid parallel above or below any underground pipeline. When laid parallel to underground pipelines or intersecting with them, the minimum clear distance shall comply with the following requirements: 1 When parallel to pipelines carrying flammable and explosive materials, it is 1000 mm; when intersecting, it is 500 mm; 2 When parallel to thermal pipelines, it is 2000 mm; when intersecting, it is 500 mm; 3 When parallel to or intersecting with water pipes or other process pipelines, it is 500 mm in both cases. 8.6.6 When a directly buried cable is connected to an outdoor junction box, a margin should be left for the portion of the cable above the ground surface. 8.6.7 For cables laid underground, clear underground markers shall be installed on the ground above them.