I prefer PVC for underground work. We just installed 500' of 4" sched 80 in 3 parallel runs Friday. They ran from the padmount transformer to the future mechanical room location for a church addition. We put them 66" below the pad and bedded them in 24" of coarse sand before backfilling. Nobody should come near these pipes, but if they do they are going to see sand before they hit PVC, I hope. The same excavator is doing all of the digging on this job. My conduits under the slab will be done the same way only they will be 48" below the slab. Well below the plumber's drains.
