It shall be unlawful for City Electrical Inspectors to engage in the business of the sale, installation or maintenance of electrical conductors, devices, appliances, apparatus, fixtures or other electrical equipment, either directly or indirectly, and they shall have no financial interest in any concern engaged in such business at any time while in the employ of the city as electrical inspectors.
(`87 Code, § 30-13) Penalty, see § 151.999