Section 193.2629 - External corrosion control: buried or submerged components(a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by-(1) Material that has been designed and selected to resist the corrosive environment involved; or(2) The following means: (i) An external protective coating designed and installed to prevent corrosion attack and to meet the requirements of §192.461 of this chapter; and(ii) A cathodic protection system designed to protect components in their entirety in accordance with the requirements of §192.463 of this chapter and placed in operation before October 23, 1981, or within 1 year after the component is constructed or installed, whichever is later.(b) Where cathodic protection is applied, components that are electrically interconnected must be protected as a unit.Amdt. 193-2, 45 FR 70407, 10/23/1980, as amended at 47 FR 32720, 7/29/1982