Low Voltage Wiring Above Class 1 area

[itjag]

I have a question that relates to installing security/voice/data/video in the area above a class 1 area. I my case its a major repair garage. Art 511 indicates that all wiring must be in conduit or use MC,MI,TC,AC cable above the 18" class 1 area. If the code permits Tray cable why not other low volt cables? I am contesting the fact that I need to have all of my security wiring in conduit above the 18" class 1 area(major truck garage).

 

[rbalex]

Section 511.7 permits Types PLTC and ITC as well.

 

[itjag]

Now I have also contacted another resource who used to be an inspector and teaches CEU classes, and he indicated that If run inside the walls the wiring does not have to be in conduit due to 511-8, the wall being the barrier to the class 1 space. He also made note that some contractors have built a dummy wall within a class1 space(sided with steel) and ran conduits up that wall to avoid the class 1 space from grade up 18"

 

[rbalex]

Now I have also contacted another resource who used to be an inspector and teaches CEU classes, and he indicated that If run inside the walls the wiring does not have to be in conduit due to 511-8, the wall being the barrier to the class 1 space. He also made note that some contractors have built a dummy wall within a class1 space(sided with steel) and ran conduits up that wall to avoid the class 1 space from grade up 18"

Assuming you are no longer dealing with Section 511.7(A)(1) (wiring above a classified location) I see no problem with using the wall as a barrier.

Something to consider: a dummy wall is unnecessary if you use Section 501.15(B)(2) Exception 1.