All electrical connections not intended for operation while submerged shall be located at least 300 mm (12 in.) above the deck of a floating orДЇixed structure, but not below the electrical datum plane. Service equipment shall disconnect when the water level reaches the height of the established electrical datum plane.Д¦82.12 Electrical Connections.

On land, the service equipment for floating structures and submersible electrical equipment shall be located no closer than 1.5 m (5 ft) horizontally from the shoreline and live parts shall be elevated a minimum of 300 mm (12 in.) above the electrical datum plane. Portion of an enclosure for electrical equipment not identified for operation while submerged shall be located below the electrical datum plane.Д¦82.11 Location of Service Equipment. Electrical equipment and transformers, including their enclosures, shall be specifically approved for the intended location. (3) In land areas subject to flooding, the electrical datum plane based on (1) or (2) above is a horizontal plane 600 mm (2 ft) above the point identified as the prevailingД¦82.10 Electrical Equipment and Transformers. (2) In land areas not subject to tidal fluctuation, the electrical datum plane is a horizontal plane 600 mm (2 ft) above the highest water level for the area occurring (1) In land areas subject to tidal fluctuation, the electrical datum plane is a horizontal plane 600 mm (2 ft) above the highest tide level for the area occurring under normalД¬ircumstances, that is, highest high tide.

The electrical datum plane as used in this article is defined as follows: The only thing I Know of in the NEC is in ARTICLE 682- NATURAL AND ARTIFICIALLY MADE BODIES OF WATER which defines the datum plain as listed belowД®lectrical Datum Plane.

Electrical datum plane