Whenever any person is engaged in making an excavation subject to this chapter, if the excavation, when left exposed, would be dangerous to persons or vehicles, the person to whom a permit is issued pursuant to this chapter shall erect a fence or railing at the excavation or work in such a manner as to prevent danger to persons, and shall so maintain such fence or railing until such work is completed or danger removed. It shall also be the duty of such person to place upon the railing or fence at sunset, suitable and sufficient red or yellow lights and keep them burning through the night during the performance of such work. (1996 Code § 25-25)