The tax hereby imposed and levied shall not apply to the following transactions, which transactions are hereby exempted from the tax:
(a) Purchases of public utility service for resale;
(b) Purchases of public utility service by the United States, the state, and the political subdivisions, municipalities, boards, commissions, authorities and public corporations thereof;
(c) Purchases of tangible personal property such as appliances or the like, as distinguished from the public service supplied;
(d) Charges for telephone services which are paid by the insertion of coins into coin- operated telephones, and specific charges or tolls for, telephone calls to points outside the corporate limits; and
(e) Nonrecurring or one-time charges incidental to the furnishing of public utility service. (1965 Code §20-12)