My boss is telling me to redline approved plans, he says that instead of having our sub trench and run conduit in the trench because of the condition of the ground (very rocky)we should propose an above ground concrete encased conduit run. I have done my homework and have not been able to find anything that speaks of this. Please help me out of another one of my boss's hair brained ideas which will in the end make me look unprofessional in the eyes of our subs.

Conduit under a minimum of 2 inches of concrete is considered as protected, no matter how deep in earth. This should be allowed by NEC Section 300.5, see Note #5 under Table 300.5.