Direct burial grounding conductor

[Magnus]

I have a main panel that is going to be turned into a sub fed panel. I therefore need to run a seperate grounding conductor to it. The run is currently direct burial with PVC stub ups. Can I direct bury dual listed thhn/thwn? I see it is listed as dry and wet locations. Reasoning: (which may be invalid ) if I can do this with bare wire, what difference would be jacketed wire with a wet location listing?
Thanks in advance
Magnus

 

[RUWired]

Can I direct bury dual listed thhn/thwn? I see it is listed as dry and wet locations. Reasoning: (which may be invalid ) if I can do this with bare wire, what difference would be jacketed wire with a wet location listing?

I would think that the following articles might prevent that use.

300.3 Conductors
(A) Single Conductors Single conductors specified in Table 310.13 shall only be installed where part of a recognized wiring method of Chapter 3.

310.7 Direct Burial Conductors
Conductors used for direct burial applications shall be of a type identified for such use.

Rick