For EMT See Section, 348-4. Uses Permitted
(a) Exposed and Concealed. The use of listed electrical metallic tubing shall be permitted for both exposed and concealed work.
(b) Corrosion Protection. Ferrous or nonferrous electrical metallic tubing, elbows, couplings, and fittings shall be permitted to be installed in concrete, in direct contact with the earth, or in areas subject to severe corrosive influences where protected by corrosion protection and judged suitable for the condition.
FPN: See Section 300-6 for information on protection against corrosion.
PS: This installation was about 300 yards from the ocean.
Joe Tedesco, NEC Consultant