555.9Electrical connections shall be located at least 305 mm (12 in.) above the deck of a floating pier. Conductor splices, within approved junction boxes, utilizing sealed wire connector systems listed and identified for submersion shall be permitted where located above the waterline but below the electrical datum field for floating piers.
All electrical connections shall be located at least 305 mm (12 in.) above the deck of a fixed pier but not below the electrical datum plane.
This rule restricts the locations of "Electrical connections" not the wiring methods used to get to them.
ARTICLE 555 Marinas and Boatyards
555.13 Wiring Methods and Installation.
(A) Wiring Methods.
(1) General. Wiring methods of Chapter 3 shall be permitted where identified for use in wet locations.
(example)
344(A)(1)....... Galvanized Steel and Stainless Steel RMC. Galvanized steel and stainless steel RMC shall be permitted under all atmospheric conditions and occupancies.
310.8(C) Wet Locations. Insulated conductors and cables used in wet locations shall comply with one of the following:
(1)Be moisture-impervious metal-sheathed
(2)Be types MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, ZW
(3)Be of a type listed for use in wet locations