46 C.F.R. § 120.370 General grounding requirements.
Title 46 - Shipping
(a) A vessel's hull must not carry current as a conductor except for the following systems: (1) Impressed current cathodic protection systems; or (2) Battery systems for engine starting. (b) Receptacle outlets and attachment plugs for portable lamps, tools, and similar apparatus operating at 100 volts or more, must have a grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor.
Title 46: Shipping
PART 120—ELECTRICAL INSTALLATION
Subpart C—Power Sources and Distribution Systems
§ 120.370 General grounding requirements.