(A)   Any person making an excavation in any street in the city shall mark and designate such excavation by lights placed thereat throughout all hours of darkness during the existence of the excavation. The lights shall be placed at the points where such excavation approaches the traveled portion of the street and shall be kept burning during all hours of darkness.  The type of lights to be used for this purpose shall be designated by the Board of Public Works and Safety of the city or its designated representative.
   (B)   Any person placing an obstruction in any street while constructing or repairing a building or other structure, or while improving or repairing the street, or in laying any conduits, wires, pipes, mains or sewers, shall mark such obstruction during the hours of darkness while it exists by lights so placed as to indicate the obstruction to any person passing along such street.
(`94 Code, § 95.49) Penalty, see § 10.99