The related work which an employee may perform is clearly limited in nature and extent by a number of requirements. One limitation is that the work must be an incident to the employee's primary occupation. The work therefore may not predominate over his primary job. He is not “employed as” an announcer, news editor, or chief engineer if his dominant employment is in work outside such occupations (see Walling v. Haden, 153 F. 2d 196, cert. denied 328 U.S. 866). For instance, an announcer who spends 40 hours of his 48 hour workweek in selling broadcasting time would not be considered to be “incidentally” engaged in such selling. Selling would in such circumstances be his primary occupation. His duties as an announcer must constitute his primary job. Another requirement is that the work of the employees must be performed “for the broadcasting company by which they are employed * * *” (see S. Rept. cited in § 793.12). Sale of broadcasting time for a company which does not employ the employee as an announcer, news editor, or chief engineer, is not exempt work. Work which is not performed for the station by which the employee is employed, is not intended to be exempt. For a discussion of the effect on the exemption of nonexempt work see §§ 793.19 to 793.21.