Is it necessary for cable trays to have a fully enclosed bottom plate?
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During a recent inspection, the inspectors found that the bottom of the cable trays in our conduit system was hollow (with horizontal grids spaced about 300–400 mm apart). They considered this to be incorrect and stated that trays with solid bottoms should be used instead. To avoid embarrassment, I didn’t argue with them. Since such a bridge frame exists, why can’t it be used? I would like to ask my friends: what are the usage regulations for different cable trays?
Trunking systems come in slot-type, tray-type, and ladder-type; as far as I know, there are no regulations prohibiting the use of ladder-type trunking in pipe racks
Power cables generally use ladder-type cable trays and do not require full enclosure. In sections of cable trays where fire protection is required, materials with fire-resistant or flame-retardant properties such as panels and meshes can be added to the cable ladders and trays to create enclosed or semi-enclosed structures. Measures such as applying fire-resistant coatings to the surfaces of the trays and their supports should also be taken, and the overall fire resistance of these structures must meet the requirements of relevant specifications or standards.
Whether it is enclosed or not is mainly related to the requirements for fireproof and explosion-proof areas
An armored cable? I think that would work; it would also help with ventilation and heat dissipation!
For power and control cables in electrical systems, T-class cable trays are generally used, as mentioned by the building owner； To achieve better shielding, instrument cable trays are generally used in the tray type. In fact, in certain areas, such as cable trenches, electrical instrument cables often cross and overlap with each other, making interference inevitable; it is therefore important to ensure proper grounding.
Interference mainly refers to control cables, that is, the grounding of control cables
In electrical systems, ladder-type cable trays are generally used, as they offer high strength and facilitate heat dissipation. Only in cases where special requirements apply, such as fire protection needs, will fireproof panels be added at the bottom on top of the ladder-type cable tray.
This post was last edited by Yu Qin on 2019-8-7 19:24. How is grounding done for control cables? I’m not familiar with this field; I’ve only heard from instrumentation control engineers that the cable trays for instrument cables need to be resistant to static electricity and should be grounded to eliminate static. I’m not sure how grounding is handled for control cables – could you explain that to me?
If the control cable is armored or has a copper shield, a copper soft grounding wire should be welded to the armor; in the case of a copper shield, it should be directly grounded by crimping it with a terminal. If neither of these features is present, then the spare core can be used for grounding, which helps to effectively address interference issues.