This Section consists of the following parts:
General “General” for descriptions and requirements applicable to systems, installations, machinery and equipment in general.
Part A “Systems” for specific requirements necessary for initial planning and basic design of electrical systems.
Part B “ Installations” for specific requirements necessary for the subsequent outfitting, selection of the machinery/equipment, etc.
Part C “Machinery and Equipment” for requirements for procured equipment.
Part D “Specialized Installations” for supplemental requirements for high voltage system, electric propulsion system and system of less than 75 kW.
Part E “Specialized Vessels and Services” for supplemental requirements for installations in special-category spaces.
General
4/5.1 Applications
Electrical apparatus and wiring systems are to be constructed and installed to the satisfaction of the Surveyor in accordance with this Section. The following are minimum requirements for classification purposes. Consideration will be given, however, to arrangements or details which can be shown to comply with other recognized standards, provided they are not less effective.
For craft having an aggregate generator capacity not exceeding 75 kW, the requirements contained in 4/5D3 are to be complied with. Electrical installations in machinery spaces with gasoline engines will be specially considered.
For passenger craft, see Section 5/1.
4/5.3 Definition
The following definitions apply for the purpose of this Section.
4/5.3.1 Earthed Distribution System
A system in which one pole of a single phase system or the neutral point of a three phase system is earthed but the earthing connection does not normally carry current.
4/5.3.2 Essential Services
Services essential for the navigation, steering and maneuvering, or for special characteristics (e.g. special services) of the craft
,
or for the safety of human life.4/5.3.3 Explosion-proof (Flameproof) Equipment Explosion-proof equipment is an equipment:
a Having an enclosure capable of:
1 Withstanding an explosion within it of a specified flammable gas or vapor, and
2 Preventing the ignition of the specified flammable gas or vapor in the atmosphere surrounding the enclosure by sparks, flashes or explosions of the gas or vapor within, and b Operates at such an external temperature that a surrounding flammable atmosphere will not be ignited.
Where explosion-proof equipment is required by this Guide, equipment certified as being flameproof as defined in IEC Publication 79 or other recognized standard may be accepted.
4/5.3.4 Hazardous Area (Hazardous Location) An area where flammable or explosive vapor, gas, or dust, or explosives may normally expected to accumulate.
4/5.3.5 Hull-return System
A system in which insulated conductors are provided for connection to one pole or phase of the supply, the hull of the craft or other permanently earthed structure being used for effecting connections to the other pole or phase.
4/5.3.6 Intrinsically-safe
A circuit or part of a circuit is intrinsically-safe when any spark or any thermal effect produced in the test conditions prescribed in a recognized standard (such as IEC Publication 79-11) is incapable of causing ignition of the prescribed explosive gas atmosphere.
a Category “ia” Apparatus which is incapable of causing ignition in normal operation, or with a single fault, or with any combination of two faults applied, with the following safety factors:
- in normal operation: 1.5 - with one fault: 1.5 - with two faults: 1.0
Above safety factors are applied to the current, voltage, or their combination as specified in 10.4.1 of IEC Publication 79-11.
4/5.3.7 Increased Safety
Type of protection applied to electrical apparatus that does not produce arcs or sparks in normal service, in which additional measures are applied so as to give increased security against the possibility of excessive temperatures and of the occurrence of arc and sparks.
See IEC Publication 79-7.
4/5.3.8 Non-Periodic Duty Rating
A rating at which the machine is operated continuously or intermittently with varying the load and speed within the permissible operating range. The load and speed variations include the overloads applied frequently, which may be greatly exceed the full load rating of the machine.
4/5.3.9 Non-sparking Fan
A fan consisting of a combination of impeller and housing which are unlikely to produce sparks by static electricity or by entry of foreign objects in both normal and abnormal conditions.
4/5.3.10 Periodic Duty Rating
A rating at which the machine is operated repeatedly on cycle of sequential loading with starting, electric braking, no-load running, rest and de-energized periods where applicable. The time for the duration of operating cycle (duty cycle) is to be 10 minutes and the ratio (i.e., cyclic duration factor) between the period of loading (including starting and electric braking) and the duty cycle is to be one of the values of 15%, 25%, 40%, or 60%.
4/5.3.11 Portable Apparatus
Portable apparatus is any apparatus served by a flexible cord.
4/5.3.12 Pressurized Equipment
Equipment having an enclosure in which positive pressure is maintained to prevent against the ingress of external atmosphere and complying with the requirements in 4/5B7.3.3.
4/5.3.13 Semi-enclosed Space
A space limited by decks and/or bulkheads in such a manner that the natural conditions of ventilation in the space are notably different from those obtained on open deck.
4/5.3.14 Separate Circuit
A circuit which is independently protected by a circuit protection device at the final sub-circuit and is dedicated to a single load.
4/5.3.15 Short Circuit
A short circuit is an abnormal connection through a negligible impedance, whether made accidentally or intentionally, between two points of different potential in a circuit.
4/5.3.16 Short-time Rating
A rating at which the machine is operated for a limited period which is less than that required to reach the steady temperature condition, followed by a rest and de-energized period of sufficient duration to re-establish the machine temperature within 2 oC (3.6 oF) of the coolant.
4/5.5 Plans and Data to Be Submitted See 4/5A1, 4/5B1, 4/5C1 and 4/5D2.3.
4/5.7 Standard Distribution System
The following are recognized as standard systems of distribution. The distribution systems differing from these will be specially considered.
- Two-wire direct current - Three-wire direct current
- Two-wire single-phase alternating current - Three-wire three-phase alternating current* - Four-wire three-phase alternating current
* Three-wire single-phase A.C. may be used in conjunction with this system for lighting.
However, the electrical distribution voltages throughout the craft
are not to exceed:
-
500 V for power, cooking, heating and other permanently connected equipment; and-
250 V for lighting, internal communications and receptacle outlets.Subject to the acceptance by the Administration, high voltage systems as outlined in 4/5D1 may be acceptable for propulsion systems.
4/5.9 Voltage and Frequency Variations
Electrical appliances supplied from the main or emergency systems other than battery supplied are to be so designed and manufactured that they are capable of being operated satisfactorily under the normally occurring variations in voltage and frequency. Unless otherwise stated, the variations from the rated value may be taken from the Table 4/5.1. Any special system, e.g. electronic circuits, which cannot operate satisfactorily within the limit shown in the Table is to be supplied through a stabilized supply.
4/5.11 Materials
All electrical equipment is to be constructed of durable and flame-retardant materials. Materials are to be resistant to corrosion, moisture, high and low temperatures, and are to have other qualities necessary to prevent deterioration in the ambient conditions the equipment may be expected to encounter.
4/5.13 Insulation Material
For the purpose of these requirements insulating material is designated as follows.
4/5.13.1 Class A Insulation
Materials or combinations of materials such as cotton, silk and paper when suitably impregnated or coated or when immersed in a dielectric liquid such as oil. Other materials or combinations of materials may be included in this class if, by experience or accepted tests, they can be shown to be capable of operation at 105 oC (221 oF).
4/5.13.2 Class B Insulation
Materials or combinations of materials such as mica, glass fiber, etc., with suitable bonding substances.
Other materials or combinations of materials, not necessarily inorganic, may be included in this class if, by experience or accepted tests, they can be shown to be capable of operation at 130 oC (266 oF).
4/5.13.3 Class E Insulation
Materials or combinations of materials which, by experience or accepted tests, can be shown to be capable of operation at 120 oC (248 oF) (materials possessing a degree of thermal stability allowing them to be operated at a temperature 15 oC (27 oF) higher than Class A materials).
4/5.13.4 Class F Insulation
Materials or combinations of materials such as mica, glass fiber, etc., with suitable bonding substances.
Other materials or combinations of materials, not necessarily inorganic, may be included in this class if, by experience or accepted tests, they can be shown to be capable of operation at 155 oC (311 oF).
4/5.13.5 Class H Insulation
Materials or combinations of materials such as silicone elastomer, mica, glass fiber, etc., with suitable bonding substances such as appropriate silicone resins. Other materials or combinations of materials may be included in this class if, by experience or accepted tests, they can be shown to be capable of operation at 180 oC (356 oF).
4/5.13.6 Insulation for Temperature Above 180 oC (356 oF)
Materials or combination of materials which by experience or accepted tests can be shown to be capable of satisfactory operation at temperature over 180 oC (356 oF) will also be considered: supporting background experience or report of tests conducted in accordance with a recognized standard ascertaining their suitability for the intended application and temperature operation are to be submitted for review.
4/5.15 Degree of Protection for Enclosure
The designation to indicate the degree of protection consists of the characteristic letters IP followed by two numerals (the "characteristic numerals") indicating conformity with conditions stated in Tables 4/5.2 and 4/5.3. The test and inspection for determining the degree of protection may be carried out in accordance with IEC Publication 529 by the manufacturer whose certificate of tests will be acceptable and is to be submitted upon request from the Bureau. Type of enclosure required for protection of equipment is to be suitable for the intended location. See 4/5B2.1.1 for selection of protective enclosure for electrical equipment based on location condition. Equipment in compliance with recognized national standards will also be considered.
4/5.17 Temperature Ratings
With the exception of equipment associated with control and monitoring systems described in 4/11, in the following requirements an ambient temperature of 40 oC (104 oF) has been assumed for locations outside of boiler and engine rooms while 45 oC (113 oF) has been assumed as the ambient temperature for the latter spaces; however, electric rotating machines in boiler and engine rooms are to be rated for an ambient temperature of 50 oC (122 oF). Where the ambient temperature is in excess of these values, the equipment's total rated temperature is not to be exceeded. Where equipment has been rated on ambient
temperatures less than those contemplated, consideration will be given to the use of such equipment, provided the total temperature for which the equipment is rated will not be exceeded. For equipment associated with control and monitoring systems described in 4/11, refer to 4/11.3.7e2.
4/5.19 Clearances and Creepage Distances
The distances between live parts of different potential and between live parts and the case or other earthed metal, whether across surfaces or in air, are to be adequate for working voltage having regard to the nature of the insulating material and the conditions of service. See 4/5C4.11.6 and 4/5D1.1.4 for additional requirements for switchboard and high voltage systems.
4/5.21 Service Trial
4/5.21.1 Electrical Installation for Craft Services All auxiliary apparatus is to be tried under working conditions. Each generator is to be run for a time
sufficient to show satisfactory operation, and parallel operation with all possible combinations is to be demonstrated. Each auxiliary motor necessary to the operation of the craft is to be run for a time sufficient to show satisfactory performance at such load as can readily be obtained. All main switches and circuit breakers are to be operated but not necessarily at full load. The operation of the lighting system, heaters, etc., is to be demonstrated satisfactorily. The entire installation is to operate to the satisfaction of the Surveyor and the drop in voltage on any part of the installation is not to exceed 6 %. See 4/5B3.1.3.
4/5.21.2 Communication Facilities
Satisfactory operation of the interior communications system required by 4/5A8 is to be demonstrated to the Surveyor during sea trials. Particular attention is to be given to demonstrating that the voice communication systems required by 4/5A8 provide the capability of carrying on a conversation while the craft is being navigated.