46 CFR 169.673 - Installation of wiring for power and lighting circuits.
(a) Wiring must be run as high as practicable above the bilges.
(b) Wiring, where subject to mechanical damage, must be protected.
(c) A wiring joint or splice must be mechanically secure and made in a junction box or enclosure.
(d) Unless a splice is made by an insulated pressure wire connector, it must be thoroughly soldered and taped with electrical insulating tape or the soldered joint must be otherwise protected to provide insulation equivalent to that of the conductors joined.
(e) Where ends of stranded conductors are to be clamped under terminal screws, they must be formed and soldered unless fitted with pressure terminal connectors.
(f) Conductors must be protected from overcurrent in accordance with their current-carrying capacities.
(g) Conductors supplying motors and motor operated appliances must be protected by a separate overcurrent device that is responsive to motor current. This device must be rated or set at not more than 125 percent of the motor full-load current rating.
(h) On metallic vessels the enclosures and frames of all major electrical equipment must be permanently grounded to the metal hull of the vessel by the mounting bolts or other means. Cable armor must not be used as the normal grounding means.
(i) On nonmetallic vessels, the enclosures and frames of major electrical equipment must be bonded together to a common ground by a normally noncurrent carrying conductor.
(j) For grounded systems the negative polarity of the supply source must be grounded to the metal hull or, for nonmetallic vessels, connected to the common ground.
(k) On a nonmetallic vessel, where a ground plate is provided for radio equipment it must be connected to the common ground.
(l) For grounded systems, hull return must not be used except for engine starting purposes.