12.4 Permissible Voltages and Distribution of Electrical Power
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Statutory Documents - IMO Publications and Documents - International Codes - DSC Code - Code of Safety for Dynamically Supported Craft – Resolution A.373(X) - Chapter 12 - Electrical Equipment - 12.4 Permissible Voltages and Distribution of Electrical Power

12.4 Permissible Voltages and Distribution of Electrical Power

  12.4.1 The electrical distribution voltages throughout the craft may be either direct current or alternating current and should not exceed:

  • (a) 500 volt for power, cooking, heating, and other permanently connected equipment; and

  • (b) 250 volt for lighting, internal communications and receptacle outlets.

The Administration may accept higher voltages for propulsion purposes.

  12.4.2 For electrical power distribution, two-wire or three-wire insulated systems should be used.

  12.4.3 In general, hull return distribution systems should not be used; however, for distribution systems with voltages under 55 volt, hull return systems may be adopted where appropriate precautions are taken for earthing; these should include:

  • (a) consideration of galvanic corrosion under normal operation; and

  • (b) consideration of the ability of the earthing points to accept fault currents without danger to the hull or from fire risk.

Such a system is permitted to be used only up to the section or distribution boards. The final sub-circuits should in all cases have an insulated return to the earthing points.

  12.4.4 The hull return system may be used for starters of main or auxiliary engines.

  12.4.5 When a distribution system for power, heating or lighting, with no connexion to earth (hull) is used, a device to monitor insulation resistance should be provided.

Parent topic: Chapter 12 - Electrical Equipment
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