Hazardous Locations - Dust Material Group Certification

[joshtrevino]

I have an instrument that is being installed in an ATEX IIIB/Zone 22 (equivalent to Class II, Division 2, Group F&G per NEC 502.6/506.6) location. The product certification is for ATEX IIIC/Zone 22 (equivalent to Class II, Division 2, Group E per NEC 502.6/506.6). The protection technique for the instrument is ATEX "tc" (by enclosure - rated for Zone 22, which is the equivalent for Class II, Div 2 per NEC 502.6). I have read in several places that a certification for Group IIIC (Group E) by implication includes Group IIIB (Groups F&G). However, NEC 500.6.B.3 (information note 2) states that "It is necessary, therefore, that equipment be identified not only for the class but also for the specific group of dust that will be present".

I think it is a certification issue, but does anyone have any input on whether the certification for my instrument allows for the installation of the instrument in the environment?

 

[rbalex]

Your problem is complying with Section 506.9(C)(2)(2). That is, an ATEX certification isn't a NRTL certification.

I usually don't reference NEC Handbook commentary, but this one is valid:

The symbol AEx identifies the equipment as meeting American national standards. In European Union countries, the symbol EEx was used historically but no longer appears in current European standards. Only equipment marked AEx has been evaluated for use in electrical systems and hazardous locations covered by the NEC.

You can possibly go the Section 500.8(A)(3)/506.9(A) route - good luck.

 

[petersonra]

the first question that should be asked is if this device is certified to US zone 22 standards or only IEC standards.