It is unlawful for any person to erect or maintain any electric fence within the city. It is further unlawful for any person to construct or maintain any fence in whole or part out of barbed wire or to use barbed wire as a guard to any parking lot or parcel of land within the city; provided, however, that fences of an elevation of not less than six feet (6') may have barbed wire strands affixed to the top thereof with the prior written approval of the building inspector. (1958 Code)