It is hereby made the duty of any person, during any excavation, to safely guard the public against any and all accidents liable to occur as a result of the same, by providing suitable and adequate warning signs, lights, safeguards, railings and guard devices around any such excavations, ditches or trenches. From sunset to sunrise, he shall place a sufficient number of warning lights or torches on each side of such excavations, trenches or ditches as is necessary to give adequate and suitable warning of danger. (1988 Code § 14-204)