technical article from Blue Sea Systems
Recreational Vessels Electrical Requirements
By Captain Tony Ford USCG (Ret.)
Note: This paper is a summary of the Coast Guard regulations for electrical systems on recreational boats and those carrying less than 6 passengers for hire. Readers should not use this document as a compliance guideline and check the prime source - the regulations.
There are three classes of Uninspected Vessels - Recreational, Fishing and Towing. Coast Guard officials do not look at fishing and towing vessels during their construction.
Recreational vessels and vessels carrying 6 or less passengers for hire may be covered by manufacturer standards. The Coast Guard has contracted with private companies for a nationwide Recreational Boat Factory Visit Program (RBFV). Qualified contractors will contact and visit recreational boat manufacturers and have been doing so since early 2001. The visits are intended to help manufacturers understand and comply with the standards but if they see violations, the representatives will make reports to the Coast Guard.
Electrical System Standards
Electrical standards are required on all boats, regardless of size, "..that have gasoline engines for electrical or mechanical propulsion, except outboard engines." If there is a gasoline engine on an inboard or inboard-outboard that is used as a generator or for propulsion, the boat must meet these standards.
Ignition Protection - Electrical components must be ignition protected if they are in a compartment with a gasoline engine or fuel tank. Inspectors will look for proof in the form of labeling. If the component is not labeled, the inspector generally will accept a statement in the manufacturer's catalog. If the component is isolated from the fuel source, ignition protection is not required. The regulations go to some length to define isolation.
Batteries - Must be secured so they cannot be moved more than 1" in any direction; terminals must be protected so that metallic objects cannot contact ungrounded terminals (positive battery terminal); and be vented to permit the discharge of hydrogen gas. Batteries cannot be installed directly above or below a fuel tank, fuel filter or fuel line fitting.
Conductors (Wires) - Look for Table 5 - which has allowable amperage for conductors. Wires must meet SAE standards J378 and J1127 or J1128. Inspectors will look for markings on the wire. If they do not find them, they will want a compliance statement from the supplier. Engine spark plug wires must meet SAE J557. Wires that pass thru bulkheads or other rigid surfaces must be protected from abrasion. 18 AWG conductors are restricted in use to 7" unprotected pigtails.
Overcurrent Protection - Manually reset, trip free circuit breakers or fuses must be at the source of power for each circuit or conductor. There are some exceptions if it is physically impractical to do so and also note that if these breakers are in an area not isolated from gasoline fuel sources, they must be ignition protected.
Original article from Blue Sea Systems