modifying contents of an Exd enclosure

[bubu]

Hello,

First of all, I'm mostly used to the European standards, so bear with me if this is a silly question.

I'm involved in a project where the contractors are wanting to replace the components within a certified Exd enclosure. Basically there's a little lcd display that they want to replace with an led one that can be networked rather than the RS485 one they have.

In Europe this is a no go since there's things like the temperature rating and the available internal volume which will be affected by the modification, but I'm told this isn't a concern when it comes to NFPA/UL requirements and I find it slightly odd. I don't have access to the UL1203 to understand the requirements but was wondering if someone can shed some light on this?

 

[petersonra]

If one modified a listed item such as this panel the modification(s) would need to be approved by the AHJ.

Generally these kind of modifications are not an issue.

In any case, none of the IEC standards are used in US classified areas. We have our own standards. They can sound the same, but they are not.

 

[bubu]

If one modified a listed item such as this panel the modification(s) would need to be approved by the AHJ.

Generally these kind of modifications are not an issue.

Thank you so much for the clarification.

So, we'd need to find the AHJ for that area and check their requirements when it comes to altering Exd boxes.

In any case, none of the IEC standards are used in US classified areas. We have our own standards. They can sound the same, but they are not.

IEC standards aren't quite the standards we have to follow in Europe either, those are the ENs which although have very similar text are not at all the same.

My doubt with regards to this is really because of the protection concept relying on available internal volume and temperature within the enclosure.

Still, thanks for the clarification.

 

[petersonra]

I don't think you can use Exd boxes in the USA.