Small craft have an ever-increasing amount of electrical equipment, systems, and associated power requirements. As a result, significantly more risks and safety concerns need to be considered in the design and testing of electrical installations on small recreational and commercial craft. Insufficient understanding of the issues associated with electrical installations and safe wiring on small craft can lead to poor practice and potential danger. For many years the electrical systems on boats consisted of 12V DC or 24V DC battery powered systems charged by a propulsion engine driven generator supplying little more than lighting and navigational aids. Nowadays, 230V AC equipment is commonplace, and craft may be fitted with a variety of domestic equipment including microwave cookers and washing machines etc, for use when connected to a shore-supply, or powered from on-board AC sources of power when cruising. Because a wider range of DC powered equipment is available and being installed by owners (including sophisticated navigational aids, GPS chart plotters, radar, audio-visual entertainment systems), additional photovoltaic and/or wind-charging systems are also being fitted to keep the commensurately larger domestic/house battery banks topped up. Often such electronic systems require special treatment and testing to minimise electro-magnetic interference. The risks regarding electrical safety on small craft are now more complex than ever and, in some instances, may be greater than many land-based installations.
Small craft have many potential hazards particular to their construction and use, for example:
- gas accumulating in poorly ventilated hull spaces.
- under/over voltages causing malfunction of equipment and damage to batteries.
- a susceptibility for damage to metal hulls and submerged metallic equipment due to galvanic and electrolytic effects.
- interruptions in power supplies or safety services.
- arcing, over-heating or burning in battery compartments which may have serious implications for both the craft and any persons on-board.
- excessive pressure and/or toxic gas emissions resulting from incorrect battery charging - particularly from Lithium-based battery technologies.
- mechanical movement of on-board equipment due to listing or pitching when navigating in rough waters or when passing other boats.
- exposure to a wide range of weather and environmental conditions.
This new On-Board Guide provides practical advice on the design, installation, testing, commissioning, and maintenance of electrical installations on small recreational and commercial craft. It summarises the existing standards and directives relative to this sector and covers key areas such as electrical supplies (including batteries and AC power sources) as well as design guidance, cable requirements, electrical protection and testing.
The full contents include:
- Working safely and general requirements.
- Types of electrical installations on-board small craft.
- Electric power sources for small craft.
- Protection against electric shock.
- Earthing.
- Distribution systems.
- Cable installation, conductor terminations and identification.
- Batteries.
- Design guidance.
- Inspection and testing of electrical installations.
The primary readers of this guide are electrically skilled boat owners, marine electrical technicians, designers and installers of electrical systems, and also those involved in boat safety examinations. The contents and coverage are applicable to the recreational and commercial small craft sectors.
