Electrical Installations
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Construction and Classification of Ships for the Carriage of Liquefied Gases in Bulk, July 2022 - Electrical Installations - Electrical Installations

Electrical Installations

Goal

To ensure that electrical installations are designed such as to minimize the risk of fire and explosion from flammable products, and that electrical generation and distribution systems relating to the safe carriage, handling and conditioning of cargo liquid and vapour are available.

10.1 Definitions

For the purpose of this chapter, unless expressly provided otherwise, the definitions below shall apply.

10.1.1 Hazardous area is an area in which an explosive gas atmosphere is or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of electrical apparatusfootnote.

10.1.1.1 Zone 0 hazardous area is an area in which an explosive gas atmosphere is present continuously or is present for long periods.

10.1.1.2 Zone 1 hazardous area is an area in which an explosive gas atmosphere is likely to occur in normal operation.

10.1.1.3 Zone 2 hazardous area is an area in which an explosive gas atmosphere is not likely to occur in normal operation and, if it does occur, is likely to do so infrequently and for a short period only.

10.1.2 Non-hazardous area is an area in which an explosive gas atmosphere is not expected to be present in quantities such as to require special precautions for the construction, installation and use of electrical apparatus.

10.2 General requirements

LR 10.2–01 The requirements of this Chapter are additional to those of Pt 6, Ch 2 of the Rules for Ships.

10.2.1 Electrical installations shall be such as to minimize the risk of fire and explosion from flammable products.

10.2.2 Electrical installations shall be in accordance with recognized standards.footnote

10.2.3 Electrical equipment or wiring shall not be installed in hazardous areas, unless essential for operational purposes or safety enhancement.

LR 10.2–02 In addition to the hazardous areas related to the carriage of flammable cargo products, other areas where flammable gas or vapour may be present are to be considered with respect to the installation of electrical equipment. These include those areas associated with the use of cargo as fuel, flammable refrigerants, batteries and storage of materials having a flashpoint (closed-cup test) not exceeding 60°C. See also Pt 6, Ch 2,14 of the Rules for Ships.

10.2.4 Where electrical equipment is installed in hazardous areas as provided in 10.2.3, it shall be selected, installed and maintained in accordance with standards not inferior to those acceptable to the Organization. Equipment for hazardous areas shall be evaluated and certified or listed by an accredited testing authority or notified body recognized by the Administration. Automatic isolation of non-certified equipment on detection of a flammable gas shall not be accepted as an alternative to the use of certified equipment.

LR 10.2–03 Where electrical equipment is to be of a ‘safe type’ in order to comply with IEC 60092: Electrical installations in ships - Part 502: Tankers - Special features, such equipment is to be certified for the gases/vapours involved. The construction and type testing is to be in accordance with an appropriate publication from the IEC 60079 series, or an equivalent National Standard.

10.2.5 To facilitate the selection of appropriate electrical apparatus and the design of suitable electrical installations, hazardous areas are divided into zones in accordance with recognized standards.

10.2.6 Electrical generation and distribution systems, and associated control systems shall be designed such that a single fault will not result in the loss of ability to maintain cargo tank pressures, as required by 7.8.1, and hull structure temperature, as required by 4.19.1.6, within normal operating limits. Failure modes and effects shall be analysed and documented to a standard not inferior to those acceptable to the Administration.footnote

LR 10.2–04 The emergency source of electrical power is also to remain operable under the conditions described in Ch 2, 2.7 Survival requirements.

10.2.7 The lighting system in hazardous areas shall be divided between at least two branch circuits. All switches and protective devices shall interrupt all poles or phases and shall be located in a non-hazardous area.

10.2.8 Electrical depth sounding or log devices and impressed current cathodic protection system anodes or electrodes shall be housed in gastight enclosures.

10.2.9 Submerged cargo pump motors and their supply cables may be fitted in cargo containment systems. Arrangements shall be made to automatically shut down the motors in the event of low-liquid level. This may be accomplished by sensing low pump discharge pressure, low motor current or low liquid level. This shutdown shall be alarmed at the cargo control station. Cargo pump motors shall be capable of being isolated from their electrical supply during gas-freeing operations.

Parent topic: Chapter 10 Electrical Installations
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