BS IEC 61892-1:2010 pdf – Mobile and fixed offshoreunits -Electrical installations Part 1 : General requirements and conditions.
4.6 MaterIals
In general. all electrical equipment shall be constructed of durable, f1ameretardant, moisture- resistant materials, which are not subject to deterioration in the atmosphere and at the temperatures to which they are likely to be exposed.
Equipment enclosures located outdoor. In naturally ventilated and wash down areas shall be made of proven seawater resistant materials.
NOTE I Such material may be seawater resistant aluminium. stamless steel or UV reslatant plastic matenal
NOTE 2 For further infomnetion regarding environmental conditions. refer to IEC 60721.3.6.
47 Power supply system characteristics
4.7.1 General
Unless otherwise stated in other parts of this standard, equipment shall function when supplied from general distflbution systems with due regard to voltage and frequency variations. harmonic distortion and conducted disturbances. The characteristics of general distribution systems are given in the following subclauses.
NOTE 1 Where the power supply is obtained from the shore, due regard should be paid ID the affect that the quatty of the supply. ii different from that specified In this clause. may have on the performance of equipment.
NOTE 2 For systems where semiconductors are connected having a total rating which is a significant portion of the total system rating, it may be feasible to suppress the harmonica Consideration should be given to taking appropriate measures to attenuate these .ff.ct of th. distribution system so that safe Operation S assured, Care Should be taken in selecting consumers supplied from an electric power supply system with a higher harmonic content than Specified in this clause
NOTE 3 Electrical equipment which requires a higher Quality power supply may need additional provisions to be made locally, Where additional equipment is fitt.d to achieve this higher quality power supply. it may be required to be duplicated and segregated to the same degree as the electrical equipment it supplies.
NOTE 4 Special atlsntion should be paid to the installaf ion of .tictñcal equipment which may influence th, quality of power supply on a local basis or react with any harmonics present on the general distribution system.
NOTE S Variable fr.quencylvoltage systems may be admissible provided safe Operation of the system is assured arid equipment is suitably rated for the espected variations.
4.7.2 AC distribution systems General
The voltages referred to in and 4.7.3 are measured at the poInt where the equIpment is installed. Voltage characteristics
Tolerances are expressed in a percentage of the nominal voltage.
Voltages are root mean square (r.m,s,) unless otherwise stated.
4.8 Electrical apparatus for explosive gas atmospheres
When an apparatus Is required to be suitable for use in explosive gas atmospheres, It shall comply with the requirements of IEC 61892.7.
Such equipment shall be constructed and tested in accordance with the requirements of the IEC 60079 series as required in IEC 61892-7 and be certified as fit for purpose for the actual ambient temperature and other environmental conditions, to the satisfaction of the appropriate authority.
NOTE In moat counlfl.a. it is required that ce,tilication Is doria by an independent testing aultioaty
4.9 Precautions against galvanic corrosion
Suitable means shall be taken to prevent galvanic corrosion when securing dissimilar metals.
for example aluminium to the structure or hull of a unit.
4.10 Clearance and distances
The distances between live parts of different potential and between live parts and the cases of other earthed metal, whether across surfaces or in air, shall be adequate for the working voltage, having regard to the nature of the insulating material and the conditions of service.
NOTE information regarding creepage and clearege distencea are given in the specific equipment standards,in IEC 61892.3
4.11 InsulatIon
Insulating materials and insulated windings shall be resistant to moisture, sea air and oil vapour, unless special precautions are taken to protect insulants against such agents.
NOTE As a consequence of his clause, insulating materials in imporlani applications, such as busbar suppoi’Ls. etc ahouid have sufficient resistance egainel tracking. It Ia recommended that the comparative tracking index of auch mat.rieia be not than 175 V when d.I.rmin.d accordan9 to PEC 60112
4.12 Maintenanc, and Inspection
Equipment shall be so designed arid installed as to permit its being maintained and inspected as required for all its parts.