What are the code requirements for crossing a buried electric line (from meter to panel) with a sewage line?
Here it's not an issue: Sewer lines have to be below frost line, so they are put at 8 feet. Electrical lines are, I think 3 feet, and can be less if protected. This of course makes it difficult to run a sewer line after the electrical is in.
I would try very hard to keep buried lines from crossing. SOMETIME one is going to be dug up for maintenance.
Code is whatever local ordinances tell you that you can do. It isn't good to cross lines but there has to be thousands of examples where you would have to so obviously it is done. Whether it is a use case, safety, or other type of reason needed is up to your local city in the US.