Is it necessary to use armored cables when using grid-type instrument trays?
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Now, in some projects, 50mm and 100mm wide mesh cable trays are used instead of conduit. In this way, before the cable enters the trough tray, a section of the cable that is located in the grid tray is relatively unprotected. In some projects, armored cables are used in combination with other cables, but this results in armored cables also being present in the tray-based cable trays, which is rather wasteful. In some projects, the standard cables that are used directly are placed in grid-type cable trays; I’m not sure if this is a safe approach
Try not to use grid-type cable trays; in our factory, from the trough-type cable trays to the primary instruments, we use galvanized pipes with a diameter of DN20.
Trunking trays are used for instrument cables, while ladder-type trays are used for electrical cables.
Our traditional concepts have not changed. Did anyone go there specifically to break those cables? Is the cable so fragile that it can’t even be touched? In current construction work, especially by foreigners, armored cables are used in conjunction with grid or trapezoidal cable trays; tray boxes, protective pipes, and flexible pipes are rarely used. Each cable in the cable tray is neatly tied up, making it easy to see at a glance and facilitating maintenance
Indeed, this design is very convenient for both initial construction and subsequent modifications. But it’s mainly a problem with armored cables, which should increase costs significantly; moreover, grid-type cable trays are likely to be more expensive than conduit as well.
Actually, the costs are more or less the same; protective tubes aren’t cheaper than raceways, while wire conduits are more expensive. There are also explosion-proof hoses, so the overall cost difference isn’t significant
Is there a conclusion on this yet? Places with a high amount of foreign investment use grid cable trays, while in China, conduit tubes are still commonly used. The biggest problem with grids is that there are no design guidelines available in China; for 50 and 100 bridge frames, slot boxes are used to protect the branch cables, and this is indicated in the installation diagrams
I have also used this approach adopted by foreigners; those of you who have relevant standards can explain why this method meets the requirements, and it would be best if it aligns with existing standards.