903.02 EXCAVATIONS; BARRICADES AND WARNING LIGHTS.
   (a)    Whenever an open excavation is being made or exists upon premises abutting upon a street, and such excavation adjoins or is within five feet of the line of the street, it shall be the duty of the owner of such premises or the agent of such owner in charge of the property to cause such excavation to be protected by substantial barriers sufficient to protect persons passing along such streets from falling into such excavation.
   (b)    Whenever an excavation is being made in any of the streets of the City under lawful authority, either for the laying, connecting or repairing of a sewer or of gas, water or other pipes, or for any other lawful purpose, it shall be the duty of the person making such excavation, and of any employee in charge of the work, to protect any and all such excavations with sufficient guards by day and lights by night, to properly warn persons passing along the street where such excavation exists.
(1957 Code §18-16)