Section 2 Alternating Current System

201. Application

1. This section is to be applied to the alternate current (a.c) electrical systems which operate at nomi- nal potentials of one pole 250 V a.c. or less on the recreational crafts. In addition to requirements in this section, the systems shall also comply with ISO 13297. However, three pole a.c. electrical

systems or one pole 250 V over a.c. electrical

(1) For alternating current systems having

systems are to comply with the following.

exceeding voltages 250 V single-phase or 500 V

three-phase, other standards in the IEC 60092 series are to be applied.

(2) For alternating current systems having not

60092-507 are to be applied.

exceeding voltages 500 V three-phase, IEC

202. General

1. The protective conductor insulation shall be green shall be used for current-carrying conductors.

2. The protective conductor shall be connected to the practicable to the battery (d.c.) negative terminal.

3. For craft with fully insulated d.c. systems (refer to

or green with a yellow stripe. Neither colour craft's d.c. negative ground (earth) as close as

ISO 10133), the a.c. protective conductor shall

be connected to the hull of a metallic hull craft, the craft external ground (earth) or the craft light- ning-protection ground plate, if fitted.

4. Metallic craft hulls shall not be used as conductors.

5. The protective conductor shall be connected to metallic hulls at a location above any anticipated water accumulation.

6. Individual circuits shall not be capable of being energized by more than one source of electrical power at a time. Each shore-power inlet, generator or inverter is a separate source of electrical power. The transfer from one power-source circuit to another shall be made by a means which opens all current-carrying conductors, live and neutral, before closing the other source circuit, pre- vents arc-over between contacts and is interlocked by mechanical or electromechanical means. Both current-carrying conductors, live and neutral, shall be broken simultaneously Vvf1en changing power sources.

7. Energized parts of electrical equipment shall be guarded against accidental contact by the use of enclosures of at least IP 2X type, in accordance with lEC 60529, or other protective means which shall not be used for non-electrical equipment. Access to energized parts of the electrical system shall require the use of hand tools or have a protection of at least IP 2X, unless otherwise specified. A suitable warning sign shall be displayed (refer to 5.2 of ISO 13297).

8. The neutral conductor shall be grounded (earthed) only at the source of power, i.e. at the onboard

generator, the secondary The shore-power neutral ed on board the craft.

of the isolation or polarization transformer, or the shore-power connection. shall be grounded through the shore-power cable and shall not be ground-

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9. A galvanic isolator or other suitable device may be fitted in the protective conductor to resist im- ported stray galvanic current flow Vv'hile permitting the passage of a.c. current, if present. Galvanic isolators shall be designed to withstand the application of power from a short-circuit test from a source capable of delivering 5000 A r.m.s. symmetrically to its output test terminals for the time required for the circuit-breaker in the test circuit to trip. After three applications of the short-circuit test, the electrical and mechanical characteristics of the isolator shall be unchanged.

203. Ignition protection

Electrical components installed in compartments which may contain liquified petroleum gases(LPG) or petrol vapour, e.g. petrol tank, engine compartment and LPG lockers, are to be designed to be compliant with ISO 8846 or in accordance with IEC 60079-0, and are to be located in accordance with ISO 9094-1.

204.

Overcurrent protection

1. General

(1) In unpolarized systems. double-pole Circuit-breakers that open both live and neutral conductors are required.

(2) Fuses shall not be Installed In unpolarized systems.

(3) Overcurrent protection devices for moto loads shall have a predetermined value of current flow that is consistent with demand-load characteristics of the protected circuit.

(4) All a.c. motor installations and each motor of a motor-operated device shall be individually pro-

tected in accordance with (3) by an integral overcurrent or thermal protection device. An ex- ception may be made for motors that will not overheat under continuous locked-rotor conditions.

(5) The rating of the overcurrent protection device shall not exceed

capacity of the conductor being protected. (refer to Table 9.1)

2. Main supply circuits

(1) Double-pole circuit-breakers shall be installed in conductors to the

(2) A manually reset trip-free circuit-breaker shall be Installed within or, if impractical, the conductor from the source of power to

the maximum current-carrying

shore-power supply circuits.

0.5 m of the source of power the panel-board circuit-breaker

shall be contained within a protective covering, such as a junction box, control box, enclosed panel-

board, or within a conduit or cable trunking or equivalent protective covering. If the loca- tion of the main shore-power inlet circuit-breaker exceeds 3 m from the shore-power inlet con- nection or the electrical attachment point of a permanently installed shore-power cord, additional fuses or circuit-breakers shall be provided within 3 m of the inlet or attachment point to the electrical

system in the craft, measured along the conductor.

(3) Overcurrent protection shall be provided for isolation and polarization transformers, including a bank of transformers operating as a unit. Each transformer shall be protected by an individual overcurrent device on the primary side, rated at not more than 125 % of the rated primary cur- rent of the transformer.

3. Branch circuits

(1) The live conductor of each branch-circuit in a polarized system shall be provided current protection, i.e. a fuse or circuit-breaker, at the point of connection to the el- board bus.

(2) Both conductors of each branch circuit in unpolarized systems shall be provided

with over- main pan-

with over-

current protection by double-pole circuit-breakers and double-pole switches, if used, at the point of connection to the main panel-board bus.

205. Ground-fault protection/earth-leakage protection

1. GFCls (RCDs) shall be of the trip-free type.

2. The craft shall be provided with earth-leakage protection in the main supply circuit by

(1) a double-pole RCD having a maximum nominal trip sensitivity of 30 mA and 100 ms maximum trip time located in accordance with 203. 2 (2) or

(2) each receptacle located in the galley, toilet, machinery space or weather deck shall be protected by a GFCI(RCD) having a maximum sensitivity of 10 mA.

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3. The GFCI (RCD) device shall have an internal circuit for manual testing of the trip function.

206. Appliances and equipment

Applicances and fixed a.c. electrical equipment installed on a craft shall have exposed conductive parts connected the the protective conductor, unless the appliance is of double-insulated construction. Integral overcurrent protection shall be provided.

207. System wiring

1. Conductors shall have a minimum rating of 300/500 V. Flexible cords shall have a minimum rating of 300/300 V.

2. Conductors and flexible cords shall be of multistrand copper, and of sizes no smaller than determined by reference to Table 9.1.

3. The insulation-temperature rating of conductors and flexible cords outside engine spaces shall least 60 °C.

4. Conductors shall be at least 1 mmË in area. An exception may be made for conductors of mum 0.75 mmË area which may be used as internal wiring in switchboards.

those be at mini-

5. Temperature ratings of conductor insulation in engine spaces shall be 70 °C minimum. The con- ductors shall be rated oil-resistant, or shall be protected by an insulating conduit or sleeving, and shall be derated in allowable current-carrying capacity in accordance with ISO 13297 annex A.

6. The protective conductor shall not have a cross-sectional area less than that of the live conductor in the supply circuit.

7. Live, neutral and protective conductors of the a.c. system shall be identified. Identification may be made by the insulation colour, by numbering or other means, if a wiring diagram for the system indicating the means of identification is supplied with the craft.

Insulation colours used, in conformance with IEC 60446:

- live conductors : black or brown

- neutral conductors : white or light blue

- protective conductors : green or green with a yellow stripe(refer to 201. 1)

208.

Installation

1. Conductor connections shall be in locations protected from the weather or in IP 55 enclosures, in accordance with IEC 60529, as a minimum. Connections above deck exposed to intermittent im- mersion shall be in IP 67 enclosures, in accordance with IEC 60529, as a minimum.

2. Conductors shall be supported throughout their length in conduits, cable trunking or trays, or by in- dividual supports at maximum intervals of 450 mm.

3. An a.c. circuit shall not be contained in the same wiring system as a d.c. circuit, unless one of the following methods of separation is used.

(1) For a multicore cable or cord, the cores of the a.c. circuit are separated from the cores of the

d.c. circuit by an earthed metal screen of equivalent current-carrying capacity to that of the largest core of the a.c. circuit.

(2) The cables are insulated for their system voltage and installed in a separate compartment of a cable ducting or trunking system.

(3) The cables are installed on a tray or ladder where physical separation is provided by a partition.

(4) A separate conduit, sheathing or trunking system is used.

(5) The a.c and d.c. conductors are fixed directly to a surface and separated by at least 100 mm

4. Current-carrying conductors of the a.c. system shall be routed above forseeable levels of bilge water and in other areas where water may accumulate, or at least 25 mm above the water level at which the automatic bilge pump switch activates.

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If conductors must be routed in the bilge area, the wiring and connections shall be in IP 67 enclo- sures, in accordance with IEC 60529, such as continuous conduit, as a minimum, and there shall be no connections below the forseeable water level.

5. Metals used for terminal studs, nuts and washers shall be corrosion-resistant and galvanically com- patible with the conductor and terminal. Aluminium and unplated steel shall not be used for studs, nuts or washers in electrical circuits.

6. Solderless crimp-on terminals and connectors shall be attached with the type of crimping tool de- signed for the termination used and for producing a connection meeting the requirements of 13.

7. All conductors shall have suitable terminals installed, i.e. no bare wires attached to stud or screw connections.

8. Screw-clamp or screwless terminals shall conform to lEC 60947-7-1. Other terminals shall be of the ring or captive-spade type, not dependent on screw or nut tightness alone for retention on the screw or stud. Captive-spade terminals shall be of the self-locking type.

An exception is that friction-type connectors may be used in circuits not exceeding 20 A if the connection does not separate when subjected to a force of 20 N.

9. Twist-on connectors(wire nuts) shall not be used.

10. Exposed shanks of terminals shall be protected against accidental shorting by the use of insulating barriers or sleeves, except those in the protective conductor system.

11. Conductors shall be routed away from exhaust pipes and other heat sources which can damage the insulation. The minimum clearances is 50 mm from water-cooled exhaust components, and 250 mm from dry exhaust components, unless an equivalent thermal barrier is provided.

12. Conductors which may be exposed to physical damage shall be protected by sheaths, conduits or other equivalent means. Conductors passing through bulkheads or structural members shall be pro- tected against insulation damage by chafing.

13. Each conductor-to-connector and conductor-to-terminal connection shall be capable of withstanding a tensile force equal to at least the value shown in Table 9.2 for the smallest conductor in the connection for 1min, without separating.

14. No more than four conductors shall be secured to one terminal stud.

209. Switchboards

1. An a.c. system switchboards with a lamp indicating the system on/off function shall be installed.

2. A system voltmeter shall be installed on the panel-board if the system is designed to supply motor circuits or if an on-board generator is installed.

3. Panel-boards shall be permanently marked with the system voltage.

4. The front side of panel-boards, i.e. the switch and circuit-breaker operating face, shall be readily accessible, and the rear side, i.e. the terminal and connection side, accessible.

5. Connections and components on panel-boards shall be in locations protected from the conformity with lEC 60529

- IP 67 as a minimum, if exposed to short-term immersion

- IP 56 as a minimum, if exposed to splashing water

- IP 20 as a minimum, if located in protected locations inside the craft

6. Craft equipped with both d.c. and a.c. electrical systems shall have their distribution separate switchboards or from a common one with a partition or other positive means

weather, in

from either provided to

separate clearly the a.c. and d.c. sections from each other, and be clearly identified. Wiring diagram

to identify circuits, components and conductors shall be included with the craft.

210. Receptacles/sockets

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1. Receptacles/sockets and matching plugs used on a.c. systems shall not be interchangeable with those used in the d.c. system on the craft.

2. Receptacles/sockets installed in locations subject rain, spray or splashing shall be able to be en- closed in IP 55 enclosures, in accordance with lEC 60529, as a minimum, when not in use. Receptacles mated with the appropriate plug shall also remain sealed, in accordance with lEC 60529.

3. Receptacles/sockets installed in areas subject to flooding or momentary submersion shall be in IP

56 enclosures, in accordance with lEC 60529, as a minimum, also meeting these requirements when in use with electrical plugs.

4. Receptacles/sockets shall be of the earthing type with a terminal provided for the protective conductor.

5. Receptacles/sockets provided for the galley area shall be located so that appliance cords may be plugged in without crossing above a galley stove or sink or across a traffic area.

6. Receptacles/sockets shall have a voltage rating in accordance with the voltage supplied by the pow- er sources.

211. Power-source options

1. Power for the a.c. system shall be supplied by one of the following means:

(1) single shore-power cable, power inlet, wiring and components with a capacity to supply the re- quired design system load;

(2) multiple shore-power cables, power inlets, wiring and components with a capacity to supply the

required design-system load;

(3) inverter supplying a.c. power from the craft's d.c. system;

(4) on-board a.c. generator(s) supplying the required system load;

(5) combination of shore-power cable(s) and on-board generator(s) used simultaneously if the craft's circuitry is arranged such that the load connected to each source is isolated from the other in accordance with 202. 6.

2. The shore-power cable(s) capacity alone, or with on-board generator(s) capacity in addition, shall be at least as large as the required system load(s).

3. A.C. generators, where installed, shall be connected to the electrical distribution system as required in 202. 6 or protected in accordance with 202. 7.

4. The power-feeder conductor from the a.c. generator shall be sized to transmit at least the gen- erator's maximum rated output and shall be protected at the generator with over current protection devices with a rating such that 120 % of the generator nominal output is not exceeded. An ex- ception may be made for self-limiting (self-adjusting) generators whose maximum over current does not exceed 120 % of its rated current output; these do not require additional external overcurrent protection.

212. Test

1. The following system tests should be performed upon completion of the a.c. installation.

(1) Residual current device (RCD) testing

(2) Continuity test of circuits, particularly ring and protective circuits

(3) Insulation resistance testing at 500 V d.c. for each circuit

(4) Polarity test at distribution and at each outlet.

213. Owner's manual

Instructions supplied by manufacturers of a.c. systems are to be included in owner's manual of Ch 1, 206. and owner's manual are to include the instructions according to ISO 13297 Annex B.

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