A separate certificate is required for each business activity which falls within the different business classification as defined in this chapter. Where two or more business activities are engaged at one location and each is taxable on the same basis and tax rate, the person may request a consolidated certificate and pay only one tax. A separate business will not be deemed to include any isolated transaction or activity that is ancillary to a primary business. (Ord. 1921 NCS §2 (part), 1993.)