Program Requirements. Some essential, basic information about your program can be found in the Graduate Programs in the Graduate Catalog, including the program description, curriculum, and contact information. Doctoral Students. For your program's handbook, go to Graduate Handbooks and select your graduate program.
The National Electric Code requires that wire placed in Schedule 80 PVC must be buried at least 18 inches below ground. If the wire is being buried without PVC, it must be at least 24 inches underground.
Schedule 40 rigid PVC conduit, elbows, that are specifically marked for underground use are suitable for use underground only by direct burial or encasement in concrete. The UL listing says both 80 and 40 can be used in both above and underground installations. Guide Information for Electrical Equipment The White Book 2013