I need to run a circuit to the opposite side of the house from the service panel to an AC disconnect box. From my understanding this could be run with THWN wire in Schedule 80 PVC above ground if it's attached to the structure (A in attached pic). If instead it was buried, Schedule 40 could be used (for any sections not above ground) but it would have to be 18" deep.
Does that rule for burying 18" deep apply if the conduit is in contact with the structure? In this case the whole run would be up against the house, I would essentially just be wrapping it around the house. It would not cross through any area with traffic. I'd like to bury it enough to keep it from being visible (2-3 inches - B in attached pic) but it would seem that digging an 18" trench all around the foundation is overkill when the same path is allowed if it's simply moved up a few inches to be above ground.