Terminal Junction Boxes in ATEX Category 2G Areas

[blaser1lt]

Hello,

New member here and I have a question concerning an ATEX Category 2G area versus Class 1, Division 1 environments or Zone 1 environments.

My company is updating an older piece of equipment and also increasing the capacity of it. The area in which the machine will be is listed as being an ATEX Category 2G environment. I have two junction boxes that I need to mount on the piece of equipment. The junction box is because there is a hose assembly from the stationary part of the machine to the moving part of the machine. The cable inside of the hose will be a Shipboard Type P, armored cable (General Cable IEEE 1580 Type P MOR Polyrad XT-125 Armored and Sheathed or equivalent) cable and the same type of cable will be used from the junction box to the devices on the moving part of the machine. The devices mounted to the moving part of the machine are a potentiometer for position indication, rated for a ATEX LCIE EEx ia IIc T4 environment (with appropriate barrier relay) and two (2) limit switches that are NEC Class 1, Division 1 rated. All devices are being powered by a 24VDC supply, the potentiometer will have a barrier relay (in order to maintain the area classification), but the limit switches (in the current installation) do not.

The installation is on an offshore oil rig that will be used primarily in Asia, and the vessel is being retrofitted in China. The equipment is mounted on the derrick above the drill floor, but will be exposed to hazardous gases as well as salt water environment.

I need to provide these two junction box enclosures from here in the US. I believe because of the area classification, the junction boxes will need to be rated for a Class 1, Division 1 environment, which would be the same as Ex d protection. Am I correct? Or will a junction box that is rated Ex e be sufficient? I am thinking that the Ex e protection will may be sufficient based on the area classification for ATEX, but I am not 100% sure for the design. If I can make the enclosure a Ex e it would make the junction box a lot smaller than what I currently have for a Ex d enclosure.

If more information is needed please let me know, I would be glad to add any additional information that is required.

Thank you for the help.

Best Regards,
John Blaser

 

[rbalex]

ATEX of itself means nothing in the US/NEC.

2G is effectively Zone 1/ Division 1. Flameproof (Ex d) and expolsionproof are generally the same concepts but are tested to significantly different standards - they are NOT the same; explosionproof is the more stringent standard.

You shouldn't be able to get an EX e or EEx e in the US unless it is also an AEx e.

To be honest, EX e (A or E) should be OK in the environment you described since you have described an intrinsically safe (EEx ia IIc T4) system in the first place.

I warned CMP14 mixing and matching NEC and IEC would lead to this confusion.

And welcome to the forums.

 

[blaser1lt]

Hello Bob,

Thank you for the reply. I probably should have mentioned that the Ex e and Ex d enclosures are being supplied by a European manufacturer, but I believe you are correct that it also has the AEx e rating on it, but I don't remember for sure, but I will check with the label sent over from the manufacturer.

I know that ATEX and US/NEC generally don't mix well. I just want to make sure that the design is safe, as with what has happened in recent years in offshore oil production, I want to make sure the design is safe.

Thank you for the explanation, and I really appreciate the help. I have learned a lot from the forums by browsing it, and glad to be a member now.

Best Regards,
John Blaser