The Merchant Shipping (Cargo Ship Construction) Regulations 1997

Main source of electrical power and main switchboard

47.—(1) Every ship in which electrical power is the only power for maintaining auxiliary services essential for the propulsion or safety of the ship shall be provided with two or more generating sets of such power that these services can be operated when any one of the sets is out of service.

(2) Load shedding or other equivalent arrangements shall be provided to protect the generators required by paragraph (1) against sustained overload.

Additional requirements for ships constructed on or after 1st September 1984

(3) A main source of electrical power shall be provided in every such ship with sufficient capacity to supply all the services required by regulation 46(1)(a) and (b). This main source of electrical power shall consist of at least two generating sets. The main source of electrical power shall be arranged so that such services can be maintained regardless of the speed and direction of rotation of the propulsion machinery or shafting.

(4) The arrangement of the generating sets required by paragraph (3) shall be such that with any one of the sets out of service—

(a) normal operational conditions of propulsion and safety of the ship and minimum comfortable conditions of habitability including those for cooking, heating, domestic refrigeration, mechanical ventilation, sanitary and fresh water can be maintained; and

(b) from a dead ship condition, the remaining sets are capable of providing the electrical services necessary to start the main propulsion plant. The emergency source of electrical power may be used for this purpose if it is capable of simultaneously supplying the emergency supplies required by Part 3 in Schedule 10 in Merchant Shipping Notice MSN 1671, or it is capable of supplying such services when combined with any other source of electrical power.

(5) Any transforming equipment supplying an electrical system referred to in this regulation shall be arranged to ensure the same continuity of supply as that required for generating sets by this regulation.

(6) The main switchboard shall be located in the same main fire zone and watertight compartment as the main generating sets in any ship with only one generating station. Where there is more than one generating station and only one main switchboard, that switchboard shall be located in the same main fire zone and watertight compartment as one of the generating stations. The Certifying Authority may permit other arrangements where other essential features of the ship render the application of this requirement impracticable subject to such alternative provisions as it may require. For the purposes of this paragraph an environmental enclosure for the main switchboard such as a machinery control room within the main boundary of the space, does not provide separation between the generating sets and switchboards.

(7) The main busbars shall be subdivided in every ship in which the total installed electrical power of the main generating sets exceeds 3 megawatt. Each section of the busbars shall be interconnected by removable links or other suitable means such that the main generating sets and any supplies to duplicated services which are directly connected to the busbars are, so far as it is practicable, equally divided between the sections. The Certifying Authority may permit other arrangements which provide equivalent system redundancy.