All persons making excavations in any streets, alleys or public grounds shall place, keep and maintain at his expense, at or near such excavation, not less than two signal lanterns and as many more as shall be necessary, and shall keep the same lighted at all hours of the night so that the excavation may be seen by any person passing along or near the excavation. The signal lanterns shall be kept lighted every night from dusk until daylight the next day, so long as the excavation remains open. (1964 Code §519.55)