Purge and pressurized NEMA4X enclosure in a Class 2 D 1 Group E classified area

[zkahn9986]

Hello, we are trying to find a suitable enclosure for C2D1 area. Now if sm1 asks me that, I would say just use a Type 9 enclosure, but the client does not want that.
So, I want to know if we can use a NEMA4X enclosure with a Z purge?
or If we place the enclosure in a non-classified area and provide JBs in the classified area, do the junction boxes in the area have to have type Z purge?

 

[rbalex]

It depends on what is inside the enclosure. But reducing Class II, Division 1 would require either a Type X or Y purge. See the NFPA 496 definitions. Type Z is only suitable for reducing Division 2. Group E is automatically Division 1. [500.5(C)(1)(3)]

That said, it is possible a Type 9 is not necessary. See NEC Section 502.10(A)(3) and note identified does not necessarily mean listed or labeled. This is what permits purged/pressurized protection in the first place.

If you want to stick your neck out, a Section 500.8(A)(3) argument might be made that a property sealed dusttight enclosure is suitable.

 

[zkahn9986]

The enclosure has VFDs, PLC, HMI, signal convertors, frequency convertors etc. The bill of materials is not drafted yet, but most likely not all of the components will be rated for C2D1. So, will a NEMA4x panel with a X or Y purge work? or if I manage to convince the client to move the panel to a non-classified area, will the junction boxes in the classified area need to be purged? these junction boxes will only have terminal blocks with all sorts of wires (signal, power).

 

[rbalex]

Did you read Section 502.10(A)(3)? :

502.10(A)(3) Boxes and Fittings.

Boxes and fittings shall be provided with threaded bosses for connection to conduit or cable terminations and shall be dusttight. Boxes and fittings in which taps, joints, or terminal connections are made, or that are used in Group E locations, shall be identified for Class II locations.