Can IP-66 enclosure be air tight? 5

[krisys]

The question here is about Ingress Protection(IP) Level as per IEC standard 60529. As per this standard, I would like to know, whether the IP-66 enclosure is air tight?

or​

Air tight IP-66 enclosure is permitted for the Hazardous area application?

I have a 6.6 kV power junction box with below specifications:
Enclosure material : Stainless steel (316L), epoxy coated, (inside & outside)
Enclosure material thickness : 2mm (min)
Enclosure Protection : Ex 'e', Zone 1, IIB, T3
Enclosure Degree of Protection : IP 66 as minimum

This junction Box is installed in the classified area (Ex rated, Hazardous Area classified).
I know that the IP-66 Enclosure means "dust tight" (first numeral 6)and protected against heavy seas or powerful jets of water (second numeral 6). But not necessarily air tight.

I want to know, whether the Ex rated equipment enclosure is permitted to be air tight? It could be a violation, because the product of internal explosion cannot have controlled release to the atmosphere.

I appreciate if someone could throw some light on this issue.

 

[krisys]

The same hydrogen generation theory holds good for power cables also.

In our case aluminum is not used. These are GI armoured cables. The galvanized (GI) armours are having the zinc coating. The hydrogen generation theory for the reaction of zinc with sea water is also now a known fact.

The cable supplier is doing an in depth study on the subject. But the fact is that the hydrogen generation and transmission through the cables is now a reality with which we have to live with now. Because the cable replacement is not feasible. So we are looking for mitigations not involving the replacement of cables.


So far the discussion is going well. I sincerely thank the contributors.
I encourage the members for "out of the box" views also.