Section 7 Switchgear and controlgear assemblies
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, July 2022 - Part 6 Control and Electrical Engineering - Chapter 2 Electrical Engineering - Section 7 Switchgear and controlgear assemblies

Section 7 Switchgear and controlgear assemblies

Parent topic: Chapter 2 Electrical Engineering

7.1 General requirements

7.1.1 The general requirements for switchgear and control gear assemblies and their components are given in IEC 61892-3:2012, Mobile and fixed offshore units – Electrical installations – Part 3: Equipment, Section 7 and Pt 6, Ch 2, 7.1 General requirements of the Rules for Ships, which are to be complied with where applicable. Special consideration shall be given for voltages above 35 kV a.c. and 1,5 kV d.c., Additions or amendments to these requirements are given in the following paragraph(s) of this sub-Section.

7.1.2 Switchgear and control gear assemblies and their components are to comply with one of the following Standards amended where necessary for ambient temperature and other environmental conditions:
  1. IEC 61439, Low voltage switchgear and control gear assemblies;
  2. IEC 62271-200, High-voltage switchgear and controlgear – Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV;
  3. IEC 62271-201, High voltage switchgear and control gear – Part 201: AC insulation-enclosed switchgear and control gear for rated voltages above 1 kV and up to and including 52 kV;
  4. IEC 60255, Electrical Relays – Part 5: Insulation coordination for measuring relays and protection equipment – Requirements and tests;
  5. IEC 62271-205, High-voltage switchgear and controlgear – Part 205: Compact switchgear assemblies for rated voltages above 52 kV;
  6. IEC 62271-203, High-voltage switchgear and controlgear – Part 203: Gas-insulated metal-enclosed switchgear for rated voltages above 52kV;
  7. alternative relevant International or National Standards. In addition, the requirements of this Section are to be complied with.

7.2 Busbars

7.2.1 The requirements for busbars and their connections are given in Pt 6, Ch 2, 7.2 Busbars of the Rules for Ships, which are to be complied with where applicable.

7.3 Circuit-breakers

7.3.1 The requirements for circuit-breakers are given in Pt 6, Ch 2, 7.3 Circuit-breakers of the Rules for Ships, which are to be complied with. Additions or amendments to these requirements are given in the following paragraph(s) of this sub-Section.

7.3.2 Circuit-breakers are to comply with one of the following standards amended where necessary for ambient temperature:
  1. IEC 60947-2, Low voltage switchgear and Control gear – Part 2: Circuit-breakers;
  2. IEC 62271-100, High-voltage switchgear and control gear – Part 100: High-voltage alternating-current circuit-breakers;
  3. IEC 62271-108, High-voltage switchgear and controlgear – Part 108: High-voltage alternating current disconnecting circuit-breakers for rated voltages of 72,5 kV and above.
  4. Alternative relevant International or National Standards. Type test reports to verify the characteristics of a circuit-breaker are to be submitted for consideration when required.

7.4 Contactors

7.4.1 The requirements for contactors are given in Pt 6, Ch 2, 7.4 Contactors of the Rules for Ships, which are to be complied with where applicable.

7.5 Creepage and clearance distances

7.5.1 The requirements for creepage and clearance distances are given in Pt 6, Ch 2, 7.5 Creepage and clearance distances 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.

7.5.2 For assemblies with a rated voltage of up to and including 1kV, the requirement of Pt 6, Ch 2, 7.5 Creepage and clearance distances 7.5.1 may met by complying with IEC 60092-302, Electrical installations in ships – Part 302: Low-voltage switchgear and controlgear assemblies.
  • Table 2.7.1 Minimum clearance distances and Table 2.7.2 Minimum creepage distances in Pt 6, Ch 2, 7.5 Creepage and clearance distances of the Rules of Ships indicate the minimum clearance and creepage distances normally allowed.
  • For assemblies installed in spaces where the environmental conditions are in excess of pollution degree 3 (that is conductive pollution occurs or dry, non conductive pollution occurs which is expected to be conductive due to condensation) as defined in IEC 61439-1, Low voltage switchgear and controlgear assemblies – Part 1: General rules; the clearance distances for non-verified assemblies are to be used.
  • A minimum creepage distance of 16 mm is permitted for assemblies verified in accordance with the requirements of IEC 61439-2, Low-voltage switchgear and controlgear assemblies – Part 2: Power switchgear and controlgear assemblies.
  • An alternative relevant National or International Standard may be used when an acceptable justification is submitted as part of the documentation required by Pt 6, Ch 2, 1.3 Documentation required for supporting evidence 1.3.3.
7.5.3 For assemblies with a rated voltage above 1kV, the requirement of Pt 6, Ch 2, 7.5 Creepage and clearance distances 7.5.1 of Rules and Regulations for the Classification of Ships, July 2022 may be met by complying with IEC 60092-503, Electrical installations in ships – Part 503: Special features – AC supply systems with voltages in the range of above 1 kV up to and including 36 kV.

An alternative relevant National or International Standard may be used when an acceptable justification is submitted as part of the documentation required by Pt 6, Ch 2, 1.3 Documentation required for supporting evidence 1.3.3.

For voltage levels above 15 kV a.c., creepage distances are to comply with manufacturer's recommendations and alternative relevant International or National Standards.

7.5.4 Suitable shrouding or barriers are to be provided in way of connections to equipment, where necessary, to maintain the minimum distances in Table 2.7.1 Minimum clearance distances in Pt 6, Ch 2, 7.5 Creepage and clearance distances of the Rules for Ships. Suitable bushing is to be provided in way of connections to equipment, where necessary, to comply with IEC 60137, Insulated bushings for alternating voltages above 1 000 V.

7.6 Degree of protection

7.6.1 The requirements for the degree of protection are given in Pt 6, Ch 2, 7.6 Degree of protection of the Rules for Ships, which are to be complied with where applicable.

7.7 Distribution boards

7.7.1 The requirements for the distribution boards are given in Pt 6, Ch 2, 7.7 Distribution boards of the Rules for Ships, which are to be complied with where applicable.

7.8 Earthing of high-voltage switchboards

7.8.1 The requirements for earthing of high-voltage switchboards are given in Pt 6, Ch 2, 7.8 Earthing of high-voltage switchboards of the Rules for Ships, which are to be complied with where applicable.

7.9 Fuses

7.9.1 The requirements for fuses are given in Pt 6, Ch 2, 7.9 Fuses 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.

7.9.2 Fuses are to comply with one of the following Standards amended where necessary for ambient temperature:
  1. IEC 60269, Low-voltage fuses;
  2. IEC 60282-1, High voltage fuses – Part 1: Current-limiting fuses;
  3. IEC 60282-2, High-voltage fuses – Part 2: Expulsion fuses;
  4. Alternative relevant International or National Standards for enclosed current-limiting fuses.

Type test reports to verify the characteristics of a fuse are to be submitted for consideration when required.

7.10 Handrails or handles

7.10.1 The requirements for handrails or handles are given in Pt 6, Ch 2, 7.10 Handrails or handles of the Rules for Ships, which are to be complied with where applicable.

7.11 Instruments for alternating current generators

7.11.1 The requirements for instruments of the alternating current generators are given in Pt 6, Ch 2, 7.11 Instruments for alternating current generators of the Rules for Ships, which are to be complied with where applicable.

7.12 Instrument scales

7.12.1 The requirements for instrument scales are given in Pt 6, Ch 2, 7.12 Instrument scales of the Rules for Ships, which are to be complied with where applicable.

7.13 Labels

7.13.1 The requirements for labels are given in Pt 6, Ch 2, 7.13 Labels of the Rules for Ships, which are to be complied with where applicable.

7.14 Protection

7.14.1 The requirements for protection are given in Pt 6, Ch 2, 6 System design – Protection, which are to be complied with.

7.15 Wiring

7.15.1 The requirements for wiring are given in Pt 6, Ch 2, 7.15 Wiring of the Rules for Ships, which are to be complied with where applicable.

7.16 Position of switchboards

7.16.1 The requirements for position of switchboards are given in Pt 6, Ch 2, 7.16 Position of switchboards 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.

7.16.2 When switchboards and section boards contain withdrawable equipment, an unobstructed space as defined by the manufacturer but not less than 1 m wide is to be provided in front of switchboards and section boards. When switchboards and section boards contain withdrawable equipment the unobstructed space is to be not less than 0,4 m wide with this equipment in its fully withdrawn position. Adequate space for operation and maintenance is to be provided around and above the switchboards and section boards.

7.16.3 So far as possible, pipes should not be installed directly above or in front of or behind switchboards, section boards and distribution boards. If such placing is unavoidable, suitable protection is to be provided in these positions, see Pt 5, Ch 13, 2 Construction and installation of the Rules for Ships and Pt 5, Ch 13, 2 Construction and installation.

7.16.4 For switchgear and controlgear assemblies, for rated voltages above 1 kV a.c., arrangements are to be made to protect personnel in the event of gases or vapours escaping under pressure as the result of arcing due to an internal fault. Where personnel may be in the vicinity of the equipment when it is energised, this may be achieved by an assembly that has been tested in accordance with Annex A of IEC 62271-200:2011, High-voltage switchgear and controlgear – Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kVor Annex B of IEC 62271-203:2011, High-voltage switchgear and controlgear – Part 203: Gas-insulated metal-enclosed switchgear for rated voltages above 52 kV and qualified for classification IAC (internal arc classification).

7.17 Switchboard auxiliary power supplies

7.17.1 The requirements for switchboard auxiliary power supplies are given in Pt 6, Ch 2, 7.17 Switchboard auxiliary power supplies of the Rules for Ships, which are to be complied with where applicable.

7.18 Testing

7.18.1 The requirements for testing are given in Pt 6, Ch 2, 7.18 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.

7.18.2 For switchgear and control gear assemblies, for rated voltages above 1 kV a.c., type tests are to be carried out in accordance with Annex A of IEC 62271-200:2011, High-voltage switchgear and controlgear – Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV or Annex B of IEC 62271-203:2011, High-voltage switchgear and controlgear – Part 203: Gas-insulated metal-enclosed switchgear for rated voltages above 52 kV and IAC (internal arc classification) assigned, to verify that the assembly will withstand the effects of an internal arc occurring within the enclosure at a prospective fault level equal to, or in excess of, that of the installation.

7.19 Disconnectors and switch-disconnectors

7.19.1 The requirements for testing are given in Pt 6, Ch 2, 7.19 Disconnectors and switch-disconnectors 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.

7.19.2 Disconnectors, switch-disconnectors and their components are to comply with one of the following standards, amended where necessary for ambient temperature and other environmental conditions:
  1. IEC 60947-3, Low voltage switchgear and control gear Part 3: switches, disconnectors, switch-disconnectors and fuse combination units;
  2. IEC 62271-102, High-voltage switchgear and control gear – Part 102: High-voltage alternating current disconnectors and earthing switches;
  3. IEC 62271-104, High-voltage switchgear and control gear – Part 104: Alternating current switches for rated voltages of 52 kv and above;
  4. Alternative relevant International or National Standards. Type test reports to verify the characteristics of a disconnector or switch-disconnector are to be submitted for consideration when required.
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