Article 502 vs 506

[HazInspector]

So I notice that article 502.6 allows for equipment suitable to 506.9 to be installed in Class II locations.

Is there an allowance within 506 for the vice versa? We are looking at supplying equipment to satisfy the requirements of 506 but there may be one or two items that can only be sourced as per the those equipment requirements and so may meet the 502 requirements.

506.7 does not allow the Class and Division classification to overlap the Zone classification so as I read it for the Zone classification method (Art 506) only equipment marked as per that article is acceptable? Am I missing something?

 

[rbalex]

It depends on whether you are installing in the US or an IEC regulated facility. (My Australian experience is very dated and, while I have a few kiwi friends, I have no NZ design experience at all)

Assuming the US, it still depends a bit on the NEC edition. Basically 506.9(C)(1) permits Division equipment to be marked for applicable Zones with certain provisions. Most reasonable US jurisdictions would recognize the equipment as suitably identified. No guarantees though. I can tell you no CENELEC jurisdiction would accept it.

 

[HazInspector]

Thanks rbalex.

This will be installed in the US. I am assuming the 2014 version of NEC is applicable?


We wouldn't dare to try to put US marked equipment in anywhere else in the world
(Why would we when we have the glorious IEC!!)
Humbly Yours.

 

[HazInspector]

I should clarify the question perhaps:

Can we install equipment marked with only Class II Division 1 markings in an area classified as Zone 21 via Article 506?

It seems that 502.6 allows the opposite.

 

[rbalex]

You must first understand that the US isn't monolithic withy respect to the NEC. Not many, but some jurisdictions still use the 2005. Quite a few are still on the 2008 and 2011 editions. See this link. The truth is most jurisdictions have no clue about Zone systems.

That said, Section 506.9(C) doesn't require Division equipment to be marked by Zones; it gives a reasonable basis for permitting additional marking without further testing. In my opinion, getting the external temperature right is the critical issue.