The maker’s name, trademark, or other identification symbol shall be placed on all electrical devices or equipment that use one hundred fifteen volts or more which are sold, offered for sale or use or used in the city. These markings and others such as voltage, amperage, wattage, and power-factor or appropriate ratings described in the 1951 edition of the National Electrical Code, shall be required, and are necessary to determine the character of the material, device or equipment and the use for which it is intended.