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§ 47 Electrical installations

Electrical systems shall be dimensioned and configured so that the required power requirements can be met in all operating modes.
Electrical installations be shall designed with safeguards and other protection so as to avoid abnormal conditions and faults that can result in danger for the personnel and the facility. Facilities shall be designed with adequate protection against e.g.
  1. electrical shock during normal use and in the event of faults,
  2. thermal effects,
  3. overcurrent,
  4. fault currents,
  5. overvoltage,
  6. undervoltage,
  7. variations in voltage and frequency,
  8. power supply failure,
  9. ignition of explosive gas atmosphere,
  10. electromagnetic interference,
  11. health hazard as a result of electromagnetic fields.
Section last changed: 01 January 2020

In order to fulfill the requirements for the dimensioning and configuration of electrical systems as mentioned in the first subsection, the IEC 61892–2 standard chapters 4 or 5 should be used. Operating modes as mentioned in the first subsection, should be stated in the facility-specific operation and maintenance strategy.
When designing electrical installations, consideration should be given to the output needs, distribution system, earthing system, protection against interruption and adequate selectivity between protections in the event of errors in the installation.
The requirement for protection against electric shock during normal operation as mentioned in litera a, entails that personnel shall not be accidentally exposed to current flow, or the current shall be limited to a non-hazardous level.
The requirement relating to protection against electric shock in the event of errors as mentioned in litera b, entails that quick, automatic disconnection of the power supply shall be provided when a failure arises that can lead to a dangerous flow of current for personnel that unintentionally come into contact with exposed parts of the installation.
The requirement relating to protection against thermal effects as mentioned in litera b, entails that detectors and suitable protection shall be used to detect and guard against abnormal heat development, arcing, fire and explosion in the installation.
The requirement relating to protection against overcurrent as mentioned in litera c, including protection against overloads and short circuits, entails that provision shall be made for automatic and selective disconnection of consumers that cause such overcurrent before it reaches a dangerous level, or that the overcurrent is limited in some other way so that it does not represent a danger.
The requirement relating to protection against fault currents as mentioned in litera d, entails that other conductors than live conductors and any other part that is intended to lead a fault current resulting from isolation failure or error, shall be able to conduct this fault current without reaching too high a temperature. Particular consideration should be given to the installation's potential earth fault currents and leakage currents.
The requirement relating to protection against overvoltage as mentioned in litera e, means that suitable protection shall be used to safeguard against hazard and accident incidents resulting from surge caused by isolation failure, faults in voltage regulators or faults between electric circuits with varying voltage, changes in load associated with connecting and disconnecting switches, earth faults and atmospheric overvoltage.
The requirement to protection against undervoltage as mentioned in litera f, means that measures shall be implemented against danger or injury resulting from the voltage returning after a full or partial cut. If such reconnection can entail a hazard, the reconnection should not take place automatically.
The requirement relating to protection against variations in voltage and frequency as mentioned in litera g, entails that the power supply shall be of such a dimension that the voltage and frequency under normal conditions lie within the tolerance limits that the installation and connected equipment are intended for.
The requirement relating to protection against power supply failure as mentioned in litera h, entails that measures shall be implemented to ensure satisfactory and reliable power supply, cf. Section 38.
The requirement relating to protection against ignition of explosive gas atmosphere as mentioned in litera i, entails that electrical equipment shall be located in unclassified areas insofar as practicable. For requirements related to area classification and plants, systems and equipment for use in areas with explosion hazard, see Sections 5 and 10.
The requirement relating to electromagnetic interference as mentioned in litera j, entails that electrical installations and equipment shall function in a satisfactory manner in their electromagnetic environment without causing unacceptable electromagnetic interference for other equipment in this environment. As regards requirements related to electrical equipment, see Regulation relating to electromagnetic compatibility (in Norwegian only), Regulations relating to EEA electromagnetic compatibility (EMC) for electronic communications equipment (in Norwegian only) and Regulations relating to equipment and safety systems for use in explosion hazardous areas (in Norwegian only).
Protection against health injury as a result of electromagnetic fields as mentioned in litera k, is in particular regulated in the Section 26 of the Radiation Protection Regulations (in Norwegian only).
For the design of electrical installations, the IEC 61892 series, including corrigendum 1 to IEC 61892-2 (2012), should be used. In those cases where the IEC 61892 series is not applicable, relevant parts of the IEC 60092 series and Regulations relating to electrical power installations (in Norwegian only) should be used.
For electrical installations on mobile facilities that are not production facilities, and that are registered in a national ship register, the DNV OS-D201 standard may be used as an alternative.