Use of LV Landscape Wire on/IN Greenroofs on Commercial Bldgs

[mpcarnahan]

We're seeing a lot more greenroofs coming around, and with it, irrigation and now landscape lighting.
There's about 4 inches of growth media (lightweight aggregate soil) up there. Any ideas if this is a code violation?

 

[hbiss]

Interesting because it's another something that the Code hasn't caught up with yet. In my opinion the wiring shouldn't be considered outside or landscape. Outdoor buried landscape LV cable isn't going to cause much of a problem if a fault causes it to burn. In this application it's actually buried in the roofing material (even though it's soil) and with only 4 inches of cover it's probably laying on the roofing membrane. If a fault occurs there is a strong possibility of damage to the membrane or fire. So unless it's CL2 it should be in conduit.

-Hal