Location of intrinsically safe barriers

[sparks25]

A while back I was told that I/S barriers or relays for I/S equipment located in C1D1 areas had to be located in the non hazardous area but could then be installed in a general purpose or a NEMA 4 enclosure. A local contractor wants to install the barriers in an XP box within the XP area. That would put both 120 Vac and I/S circuits within the enclosure (on opposite sides of the barrier) in the Classified area. I could not find anything in the code prohibiting that. Looking for an article prohibiting or restricting it.
Any help appreciated

 

[rbalex]

It's not so much a prohibition as what must be done in addition for the wiring to become Code compliant. Of course, the purpose of barriers is to separate IS from non-IS conductors of a circuit so, no matter what the enclosure Type, it must be done per Section 504.30(A)(2).

There are other considerations as well. Where is the control drawing that permits the contractor's proposed installation? Seals may also need to be considered and because non-IS conductors are entering the enclosure, they need to be sealed per Section 501.15(C) rather than 504.30.