Can armored cables in explosion-proof areas be used without flexible conduits?

I also couldn’t find any relevant standards; it’s just that some experts who came to inspect it approved it. The self-control installation manual also contains installation diagrams; the cables in the explosion-proof areas are not connected to explosion-proof hoses, but rather to explosion-proof couplings. I haven’t seen any experts support this approach – they always say it’s not explosion-proof and unsafe. It’s difficult to explain this to experts, and the people from the design institute are also at a loss.

It is not necessary to use a flexible tube. As long as the instruments, junction boxes, etc. meet the explosion-proof requirements, including the sealed joints (glands). In fact, the flexible tube itself only serves to protect the cable; it does not have the function of separating hazardous areas from safe areas. In many of our projects abroad, armored cables are laid directly. Additionally, unarmored cables can also be laid directly for the same reason.

For wiring in explosion-proof areas, we just need to connect it to the explosion-proof junction box

There are currently two types of explosion-proof cable connectors: one is called a gland, also known as an explosion-proof cable sealing joint; the other is an explosion-proof isolation sealing joint, also referred to as a horn connector. Grundfos has direct electrical connections; since it is explosion-proof, there is no need to use explosion-proof flexible hoses. Even if such hoses were used, they would be of no use for providing explosion protection, but they do help improve the aesthetic appearance. For the installation using elbow connectors, an explosion-proof flexible tube must be used for the electrical connections before connecting the elbow connectors; explosion-proof putty is then filled inside these elbows. However, this method is no longer commonly used due to electrical regulations that require the explosion-proof distance to be no more than 450 units.