The provisions of Sections 3, 4.2, and 4.3 of this Act do not apply to electrical contractors, to agencies or instrumentalities of the State of Illinois or of the United States, to units of local government, their agents or representatives, that have contracted with the recyclable metal dealer in the disposal of its metal street signs, to common carriers or to purchases from persons, firms or corporations regularly engaged in the business of manufacturing recyclable metal, the business of selling recyclable metal at retail or wholesale, in the business of razing, demolishing, destroying or removing buildings, to the purchase of one recyclable metal dealer from another or the purchase from persons, firms or corporations engaged in either the generation, transmission or distribution of electric energy or in telephone, telegraph and other communications if such common carriers, persons, firms or corporations at the time of the purchase provide the recyclable metal dealer with a bill of sale or other written evidence of title to the recyclable metal.