Section 11 Electrical cables and busbar trunking systems (busways)

11.1 General

11.1.1 The general requirements of electrical cables, optical fibre cables and busbar trunking systems (busways) are given in Pt 6, Ch 2, 11.1 General of the Rules for Ships and IEC 61892-4 (all parts), Mobile and fixed offshore units – Electrical installations – Part 4: Cables, which are to be complied with where applicable

11.2 Testing

11.2.1 The requirements for testing are given in Pt 6, Ch 2, 11.2 Testing of the Rules for Ships, which are to be complied with where applicable. Additions or amendments to these requirements are given in the following paragraph(s) of this sub-Section.

11.2.2 For cables with rated voltage above 30 kV a.c. guidance for requirements and test methods can be obtained from IEC 60840, Power Cables with extruded insulation and their accessories for rated voltages above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV) – Test methods and requirements.

11.3 Voltage rating

11.3.1 The requirements for voltage rating are given in Pt 6, Ch 2, 11.3 Voltage rating of the Rules for Ships, which are to be complied with where applicable.

11.4 Operating temperature

11.4.1 The requirements for operating temperature are given in Pt 6, Ch 2, 11.4 Operating temperature of the Rules for Ships, which are to be complied with where applicable.

11.5 Construction

11.5.1 The requirements for construction are given in Pt 6, Ch 2, 11.5 Construction of the Rules for Ships, which are to be complied with where applicable.

11.6 Conductor size

11.6.1 The requirements for conductor sizing are given in Pt 6, Ch 2, 11.6 Conductor size of the Rules for Ships, which are to be complied with where applicable. Additions or amendments to these requirements are given in the following paragraph(s) of this sub-Section.

11.6.2 The cable current ratings given in Pt 6, Ch 2, 11.6 Conductor size 11.6.5 and Pt 6, Ch 2, 11.6 Conductor size 11.6.5 in Pt 6, Ch 2, 11.6 Conductor size of the Rules for Ships are based on the maximum rated conductor temperatures given in Pt 6, Ch 2, 11.4 Operating temperature 11.4.2 in Pt 6, Ch 2, 11.4 Operating temperatureof the Rules for Ships. When cable sizes are selected on the basis of precise evaluation of current rating based upon experimental and calculated data, details are to be submitted for consideration. Alternative short-circuit temperature limits, other than those given in Table Pt 6, Ch 2, 11.6 Conductor size 11.6.5, may be applied using the data provided in:

IEC 60724, Short-circuit temperature limits of electric cables with rated voltages of 1kV (Um=1,2kV) and 3kV (Um=3,6kV); or
IEC 60986, Short-circuit temperature limits of electric cables with rated voltages from 6kV (Um=7,2kV) and up to 30kV (Um=36kV).
IEC 61443, Short-circuit temperature limits of electric cables with rated voltages above 30 kV (Um = 36 kV).

Alternative short-circuit temperature limits provided in an acceptable and relevant National Standard may also be considered.

11.7 Correction factor for cable current rating

11.7.1 The requirements for the correction factor for cable current rating are given in Pt 6, Ch 2, 11.7 Correction factors for cable current rating of the Rules for Ships, which are to be complied with where applicable.

11.8 Installation of cables

11.8.1 The requirements for installation of cables are given in Pt 6, Ch 2, 11.8 Installation of electric cables of the Rules for Ships and IEC 61892-6:2007, Mobile and fixed offshore units – Electrical installations – Part 6: Installation, Section 5, which are to be complied with where applicable. Additions or amendments to these requirements are given in the following paragraph(s) of this sub-Section.

11.8.2 The minimum internal radius of bend for the installation of fixed electric cables is to be chosen according to the construction and size of the cable and is not to be less than the values given in Pt 6, Ch 2, 11.8 Installation of electric cables 11.8.6 in Pt 6, Ch 2, 11.8 Installation of electric cables of the Rules for Ships. Bends in fixed electric cable runs are only to be in accordance with the cable manufacturer’s recommendations if the recommended bending radii are greater than the values given in Pt 6, Ch 2, 11.8 Installation of electric cables 11.8.6 in Pt 6, Ch 2, 11.8 Installation of electric cablesof the Rules for Ships.

11.8.3 All cables as far as is practicable are to be located outside areas at risk of cryogenic spill.

11.9 Mechanical protection of cables

11.9.1 The requirements for mechanical protection of cables are given in Pt 6, Ch 2, 11.9 Mechanical protection of cables of the Rules for Ships, which are to be complied with where applicable.

11.10 Cable support system

11.10.1 The requirements for the cable support system are given in Pt 6, Ch 2, 11.10 Cable support systems of the Rules for Ships, which are to be complied with where applicable. Additions or amendments to these requirements are given in the following paragraph(s) of this sub-Section.

11.10.2 The distances between the points at which the cable is supported (e.g. distances between ladder rungs, support brackets, hangers, etc.) are to be chosen according to the construction of cable (i.e. size and rigidity) and the probability of vibration and are to be generally in accordance with those given in Pt 6, Ch 2, 11.10 Cable support systems 11.10.3 in Pt 6, Ch 2, 11.10 Cable support systems of the Rules for Ships or manufacturer's recommendations, whichever requires a smaller distance between supports.

11.11 Penetration of bulkheads and decks by cables

11.11.1 The requirements for penetrations of bulkheads and decks by cables are given in Pt 6, Ch 2, 11.11 Penetration of bulkheads and decks by cables of the Rules for Ships, which are to be complied with where applicable.

11.12 Installation of electric and optical fibre cables in protective casings

11.12.1 The requirements for installation of electric and optical fibre cables in protective casings are given in Pt 6, Ch 2, 11.12 Installation of electric and optical fibre cables in protective casings of the Rules for Ships, which are to be complied with where applicable.

11.13 Non-metallic cable support systems, protective casings and fixings

11.13.1 The requirements for non-metallic cable support systems, protective casings and fixings are given in Pt 6, Ch 2, 11.13 Non-metallic cable support systems, protective casings and fixings of the Rules for Ships, which are to be complied with where applicable.

11.14 Single-core electric cables for alternating current

11.14.1 The requirements for single-core electric cables for alternating current are given inPt 6, Ch 2, 11.14 Single-core electric cables for alternating current of the Rules for Ships, which are to be complied with where applicable.

11.15 Electric cable ends

11.15.1 The requirements for electric cable ends are given in Pt 6, Ch 2, 11.15 Electric cable ends of the Rules for Ships, which are to be complied with where applicable.

11.16 Joint and branch circuits in cable systems

11.16.1 The requirements for joint and branch circuits in cable systems are given in Pt 6, Ch 2, 11.16 Joints and branch circuits in cable systems of the Rules for Ships, which are to be complied with where applicable.

11.17 Busbar trunking systems (bustrunks)

11.17.1 The requirements for busbar trunking systems (bustrunks) are given in Pt 6, Ch 2, 11.17 Busbar trunking systems (bustrunks) of the Rules for Ships, which are to be complied with where applicable. Additions or amendments to these requirements are given in the following paragraph(s) of this sub-Section.

11.17.2 Where the busbar trunking system is employed for circuits on and below the freeboard deck, arrangements are to be made to ensure that circuits on other decks are not affected in the event of partial flooding under the normal angles of inclination given in Pt 6, Ch 2, 1.10 Inclination of the unit for essential electrical equipment.