I would have thought that not dying from electric shock must be a pretty timeless body of knowledge What gauge of copper conductor is required for 50m run to

I would have thought that not dying from electric shock must be a pretty timeless body of knowledge What gauge of copper conductor is required for 50m run to a 30A 240v recepticle? What type of conductors are allowed if that run is outdoors a underground? How deep does the trench need to be? What over current protection is required? And so on.