6 Engine electrical systems and components
6.1 D.C. installations
6.1.1 Extra-low-voltage d.c. wiring, i. e. less than 50 V shall conform with ISO 10133.
6.1.2 The d.c. negative ground/earth for electrical systems shall be of two types:
- either fully insulated earth return, or
- ground earth return.
Electrical starting and stopping aids such as glow plugs or induction air heaters (and those using buzz bar connections) and cranking motors shall be activated by remote relays, so as to minimise fire hazards due to potential arcing at terminal connections and short circuits from extended lengths of heavy current draw cables.
6.2 Cranking motors
Earth return cranking motors shall be earthed (d.c. negative ground) to the boat grounding system.
6.3 Alternators
Where alternators are exposed to spillage of coolants, fuel or lubricating oil during top up, a suitable shielding shall be provided.
6.4 Wiring and connections
6.4.1 Cables and wires shall be sized in accordance with ISO 10133.
6.4.2 Where wires or cable are bundled into looms or harnesses cable lengths emerging from the loom shall be of adequate length to prevent stressing of the cable and connections and chafing of the insulation.
6.4.3 Cables and wires and looms shall be kept and secured well clear of rotating shafts couplings, belts, etc.
6.4.4 Cables or looms shall be supported using suitable clips that have no sharp chafing edges at no more than 250 mm intervals.
6.5 Relays, fuse boxes and electronic control modules (ECMs)
Relays, fuses and ECMs shall have a minimum protection according to IP 55 rating to minimise the risk of short circuits.
6.6 Integral and remote stop solenoids systems
6.6.1 Energised to stop systems shall be provided with a stop override system that may be of the lever type.
6.6.2 Remote stop solenoids shall be accessible for inspection and maintenance.
Bibliography
[1] ISO 8846: 1990, Small craft - Electrical devices - Protection against ignition of surrounding flammable gases.
[2] ISO 8849: 1990, Small craft - Electrically operated bilge-pumps.
[3] ISO 9227:1993, Corrosion tests in artificial atmospheres - Salt spray tests.
