Example 1. Employer B, who operates a farm and a store, employs A to perform services in connection with both operations. A's services on the farm are such that they are excepted as agricultural labor and do not constitute employment, and his services in the store constitute employment. He is paid at the end of each month. During a particular month A works 120 hours on the farm and 80 hours in the store. None of A's services during the month are deemed to be employment, since less than one-half of his services during the month constitutes employment. During another month A works 75 hours on the farm and 120 hours in the store. All of A's services during the month are deemed to be employment, since one-half or more of his services during the month constitutes employment.
Example 2. Employee C is employed as a maid by D, a medical doctor, whose home and office are located in the same building. C's services in the home are excepted as domestic service and do not constitute employment, and her services in the office constitute employment. She is paid each week. During a particular week C works 20 hours in the home and 20 hours in the office. All of C's services during that week are deemed to be employment, since one-half or more of her services during the week constitutes employment. During another week C works 22 hours in the home and 15 hours in the office. None of C's services during that week are deemed to be employment, since less than one-half of her services during the week constitutes employment.
26 C.F.R. §31.3306(d)-1