BS IEC 61892-5:2000 pdf download.Mobile and fixed offs. hore units - Electrical installations
1 Scope
This part of IEC 61892 specifies the characteristics for electrical installations in floating units,for use during transfer from one location to another and for use during the exploration and exploitation of petroleum resources.
NOTE Attention is drawn to further requirements concerning electrical installations on such mobile offshore units contained in the MODU CODE of the International Maritime Organization (IMO).
2 Normative references
The following normative documents contain provisions which, through reference in this text,constitute provisions of this part of IEC 61892. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of IEC 61892 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards.
4 General requirements
4.1 In every mobile unit in which electric power is used for the services necessary for the safety of the unit， the generators, switchgear, motors and associated controlgear for such services, with the exception of machinery in the platform of semi-submersibles, shall be so situated or arranged that they continue to operate satisfactorily in the event of partial flooding by bilge water above the tank top in the space in which they are situated. The design criterion for partial flooding shall be assumed to be a depth of water 1/12h beam but not exceeding a depth of 1,5 m except where this requirement is impracticable for horizontally mounted propulsion generators and motors. In such circumstances the machine enclosures shall, at least, be watertight to the underside of the shaft.
4.2 Rotating machines shall be installed to minimise the effects of motion. The design of bearings of all machines and the arrangement for their lubrication shall be adequate to withstand the motions encountered in heavy weather and operation for prolonged periods at the list and trim specified in clause 5 without the spillage of oil.
4.3 Conductors and equipment shall be placed at such a distance from each magnetic compass or shall be so disposed that the interfering external magnetic field is negligible; that is, the total singular deviation shall not exceed 30 minutes when any combination of circuits is switched on and off.
4.4 Where the total installed electrical power of the main generators exceeds 3 MW the busbars of the main switchboard shall be subdivided into at least two parts. The subdivision may be effected by removable links, circuit-breakers or other suitable means so that the main generators and any supplies to duplicated services which are directly connected to the busbars are, as far as is practicable, equally divided between the sections.BS IEC 61892-5 pdf download.