Is this installation explosion-proof?
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This post was last edited by ssln123 on 2019-1-13 at 17:02. 1 is an explosion-proof flexible tube, 2 is a galvanized protective tube, and 3 is an explosion-proof tee (the port facing downward is empty; it is likely used for drainage). Is this installation method in compliance with explosion-proof requirements? Worried that small insects might get inside that empty opening? That flammable gases could get in through there? That corrosive gases could get in through there?
We have this situation too. The key is to check whether the wires inside this explosion-proof tee are connected; if there are connections, it will be difficult to ensure explosion protection.
Explosion-proof boxes with terminals must be equipped with explosion-proof connectors on the outside, as well as special sealing rings for sealing
This is a very common issue; in my opinion, ensuring proper sealing of all joints should resolve the problem. The opening facing downward is for drainage; we used a drain valve on site. Even if you seal this area, the cables inside the cable tray will still be in the same condition, and it’s not possible to completely seal the cable tray.
Such modifications are quite common on site; many issues arise due to construction problems, which lead to water seepage. A drainage outlet is installed in such cases, but this usually draws attention during safety inspections. Our solution is to use a tee connection and seal the extra outlet with mortar, so that there are no problems during inspections and drainage is still possible, though it may be slower. The amount of water that seeps in isn’t very large anyway. As for sealing, it’s hard to say – as mentioned earlier, even cable trays can’t guarantee perfect sealing. But generally, there are no problems, and I’ve never heard of fires occurring because of instruments or similar devices
1 just connects directly to 2, and that’s it. 3 is extra; the downward opening is open, so it’s no longer explosion-proof
If it’s intrinsically safe, then it’s explosion-proof, right?:)
Try to use a single cable from start to finish; more connectors increase the risk
If installed as required, it is explosion-proof; the connection between the explosion-proof tee and the flexible tube needs to be filled with filler. The port at the bottom of the explosion-proof tee is used for drainage, which I find to be very useful. In practice, it would be best to add an explosion-proof gasket between the flexible tube and the instrument junction box – this is just for reference
Normally, the lower outlet of this tee is sealed with a plug; however, the explosion protection of cable trays and conduit systems does not depend on their insulating properties, but rather on the quality of the cables and their flame-retardant characteristics……
Normally, the lower outlet of this tee is sealed with a plug; however, the explosion protection of cable trays and conduit systems does not depend on their insulating properties, but rather on the quality of the cables and their flame-retardant characteristics……