No person shall engage in the business of installing, maintaining, altering or repairing for others within the City any electric wiring, devices, appliances or equipment unless the person shall have received an electrical contractor's license and a certificate therefor, nor shall any person, except a person employed by and working under the direction of a holder of an electrical contractor's license or an electrician's license, in any manner undertake to execute any work of installing, maintaining, altering or repairing any electric wiring, devices or equipment unless the person shall have received either an electrical contractor's license and a certificate therefor, or an electrician's license and a certificate therefor, except that no license shall be required in order to execute the following work:
(a) For any work involved in the manufacture, test or repair of electric materials, devices, appliances or apparatus, but not including any permanent wiring other than that required for testing purposes.
(b) For the assembly, erection and connection of electric apparatus and equipment by the manufacturer of the apparatus and equipment, but not including any electrical wiring other than that involved in making electric connections on the apparatus or equipment itself, or between two or more parts of the apparatus or equipment.
(c) For minor repair work, for the replacement of lamps or for the connection of portable devices to suitable receptacles which have been permanently installed.
(d) For the installation of wiring, devices, appliances and equipment for the operation of signals or the transmission of information, where the wiring devices, appliances or equipment operate at a voltage of not exceeding fifty between conductors and do not include generating or transforming equipment capable of supplying more than fifty watts of energy.
(e) For authorized persons of the utility company supplying power to install service conductors from pole to service head, to maintain service and distribution lines and to maintain their power producing equipment.
(1957 Code §1143.01)