Questions regarding flexible hoses
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As is well known, instruments in explosion-proof areas need to be connected to galvanized steel pipes using explosion-proof flexible connectors. However, I have a question I’d like to ask everyone: for instruments that are not subject to explosion-proof requirements or are not located in explosion-proof areas, what kind of protection should be used for their cables? Is it still a flexible pipe + galvanized steel pipe? What kind of flexible pipe is it? Are there any relevant product specifications or guidelines available? Since I have only been working in design for less than a year, and my previous experience has been in explosion-proof areas, I haven’t delved deeply into this issue. I hope everyone can offer some suggestions; thank you
In explosion-proof areas, armored branch cables connected with explosion-proof armored connectors can be used; in non-explosion-proof areas, flexible rubber seals that are waterproof and dustproof can be employed for connection, while for a cheaper solution, plastic waterproof and dustproof connectors can be used to connect directly to the cables. The main idea is to prevent mechanical damage, as well as protect against water and dust. In explosion-proof areas, consideration is given to explosion-proof sealing and armoring
Okay, thank you{:1_90:}
No one has discussed this issue in depth, because it is a question for elementary school students.
The cables are explosion-proof; they can be laid from the main cable tray, through secondary cable trays or galvanized steel pipes, to the instruments and valve accessories. Some of the cables can be connected to the instruments and valves using explosion-proof connectors, and it is not necessary to use explosion-proof flexible conduits
Now, explosion-proof pipes are no longer needed in many places~!
But since there is some distance between the cable tray or galvanized pipe and the instrument, it’s better to use flexible tubing for the connection. Or are there any specific regulations that require this?
There are no mandatory regulations; in the past, instruments were powered with high voltage and used explosion-proof wiring tubes in accordance with electrical design standards. Nowadays, most instruments operate at 24V, or even in intrinsically safe configurations. Explosion-proof flexible tubes are consumable items; if left exposed for too long, they will explode and get damaged at the slightest touch. Many design institutes design them in the traditional way *with explosion-proof flexible tubes.
In actual use, the owner’s suggestions are followed; previously, flexible pipes equipped with stainless steel braided wire armor and explosion-proof sealed joints were used to lead the cables to the instrument points on site, which eventually led to water accumulation. So the owners’ current opinion is generally to avoid using flexible pipes, as water accumulated in such pipes is not visible, and prolonged exposure of the joints to water can lead to moisture seeping into the interior of the device. Secondly, most of the current solutions involve junction boxes along with branch cables; after all, it’s a way to save money, and that’s how EPC projects are carried out. If there are multiple failure points, then there are multiple failure points.