No person shall make any excavation or opening or dig any ditch, trench, tunnel, or hole in, along, across, or under any street, sidewalk, or other public place for the purpose of laying or placing therein any pipe, wires, or poles or for any other purposes unless a written permit therefor has been issued by some officer of the village vested with proper authority, provided, that a permit shall not be required where the work is performed under a contract with the village, but in the event the work requires a sidewalk or street to be wholly or partially obstructed, the party performing the work shall notify the village at least two hours before obstructing the sidewalk or street, unless prevented by sudden emergency.