Senior Member
I have solar install where the EMT conduit containing DC conductors go from on building to another. However in between goes underground and HDPE is shown to be used.

Has anyone used HDPE for underground install? Can you even do it? 353 says direct buried earth or concrete but was wondering if anyone had problems


Senior Member
I don't really know anything about HDPE but 690.31(A) for solar systems says: "All raceway and cable wiring methods included in this Code ... shall be permitted."