It does not include the related activities performed for such an enterprise by an independent contractor, such as an independent accounting firm or sign service or advertising company, * * * (S. Rept. No. 145, 87th Cong., 1st Sess., p. 40).
The term "independent contractor" as used in section 3(r) has reference to an independent business which performs services for other businesses as an established part of its own business activities. The term "independent contractor" as used in 3(r) thus has reference to an independent business which is a separate "enterprise," and which deals in the ordinary course of its own business operations, at arms length, with the enterprises for which it performs services.
29 C.F.R. §779.233