Section 1 Direct Current System

101. Scope

1. This section is to be applied to the extra-low-voltage direct current (d.c) electrical systems which operate at nominal potentials of 50 V d.c. or less on the recreational crafts. It specifies the require- ments for the design, construction and installation of the d.c electrical systems but engine wiring as supplied by the engine manufacturer is not covered by this section. However, the craft operated by alternating current systems shall comply with the Sec 2.

2. In addition to requirements in this section, the systems shall also comply with ISO 10133 (Extra-low- voltage d.c. installations). However, for the direct current (d.c) electrical systems exceed- ing d.c. 50 V, other standards in the IEC 60092 series are to be applied.

3. Requirements for electrically operated direct-current bilge pumps applies to the pumps rated for less than 50 V direct current, the pumps intended for use in removing bilge water from the recreational crafts and also shall comply with ISO 8849 (Electrically operated direct-current bilge pumps). This pumps do not cover pumps intended for damage control.

102. General

1. Electrical systems shall be designed and installed so as to ensure proper operation of the craft un- der normal conditions of use and shall be such as to minimise risk of fire and electric shock.

2. Attention shall be paid to the provision of overload and short-circuit protection of all circuits, ex- cept engine starting circuits, supplied from batteries.

3. Ventilation shall be provided to prevent the accumulation of gases, which might be emitted from batteries. Batteries shall be firmly secured and protected from ingress of water.

4. The system type shall be either a fully insulated two-wire d.c. system or a two-wire d.c. system with a negative ground. The hull shall not be used as a current-carrying conductor. Engine-mounted wiring systems may use the engine block as the grounded conductor.

5. An equipotential bonding conductor, if fitted, shall be connected to the craft's ground(earth) to min- imize stray current corrosion.

6. Switches and controls shall be marked to indicate their use, unless the purpose of the switch is ob- vious and its mistaken operation will not cause a hazardous condition.

7. Protective devices such as circuit-breakers or fuses shall be provided at the source of power, e.g the panel-board(switchboard), to interrupt any overload current in the circuit conductors before heat can damage the conductor insulation, connections or wiring-system terminals. The selection, arrange- ment and performance characteristics should be such that the following is achieved.

(1) maximum continuity of service to healthy circuits under fault conditions through selective oper- ation of the various protective devices.

(2) protection of electrical equipment and circuits from damage due to overcurrents, by coordination

of the electrical characteristics of the circuit or apparatus and the tripping characteristics of the protective devices.

8. All d.c. equipment shall operate under the voltage range of accumulator terminals like below (1).

Except where the circuit includes equipment requiring a higher minimum voltage, the specified min-

imum voltage shall be used in the calculation of the conductor size (refer to (2))

(1) for a 12 volt system : 10.5 ~ 15.5 V, for a 24 volt system : 21 ~ 31 V

(2) the voltage drop Á(V) may be calculated by the following formula

ŊĦŊËÈĖ×Â× Ä Á G JÅ

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where

Å :

 :

Ä :

the cross-sectional area of the conductor(mmË) load current (A)

the length (m) of the condition from the positive power source to the electrical device and back to the negative source connection.

9. The length and cross-sectional area of conductors in each circuit shall be such that the calculated voltage drop shall not exceed 10 % of the nominal battery voltage for any appliance, when every appliance in the circuit is switched on at full load.

10. Electrical systems shall comply with the ISO 8846 in order to protect against ignition of sur- rounding flammable gases.

103. Batteries

1. Batteries shall be permanently installed in a dry, ventilated location above the anticipated bilge-wa- ter level.

2. Batteries shall be installed in a manner to restrict their movement horizontally and vertically consid- ering the intended use of the craft. A battery, as installed, shall not move more than 10 mm in any direction when exposed to a force corresponding to twice the battery weight.

3. The batteries installed in the craft shall be capable of inclinations of up to 30° without leakage of electrolyte. In monohull sailing craft, means shall be provided for containment of any spilled elec- trolyte up to inclinations of 45°.

4. Batteries shall be installed, designed or protected so that metallic objects cannot come into uninten- tional contact with any battery terminal.

5. Batteries, as installed, shall be protected against mechanical damage at their location or within their enclosure.

6. Batteries shall not be installed directly above or below a fuel tank or fuel filter.

7. Any metallic component of the fuel system within 300 mm above the battery top, as installed, shall be electrically insulated.

8. Battery cable terminals shall not depend on spring tension for mechanical connection to them

104.

Battery-disconnect switch

1. A battery-disconnect switch shall be installed in the positive conductor from the battery, or group of batteries, connected to the supply system voltage in a readily accessible location, as close as practical to the battery or group of batteries. The following constitute exceptions.

(1) outboard-powered craft with circuits for engine starting and navigation lighting only

(2) electronic devices with protected memory and protective devices such as bilge-pumps and alarms, if individually protected by a circuit-breaker or fuse as close as practical to the battery terminal

(3) ventilation exhaust blower of engine/fuel-tank compartment if separately protected by a fuse or circuit-breaker as close as practical to the battery terminal

(4) charging devices which are intended to be used when the craft is unattended (e.g. solar panels,

wind generators) if individually protected by a fuse or circuit-breaker as close as practical to the battery terminal.

2. The minimum continuous rating of the battery switch shall be at least equal to the maximum cur- rent for which the main circuit-breaker is rated and also the intermittent load of the starter motor circuit, or the current rating of the feeder conductor, whichever is less.

3. Remote-controlled battery-disconnect switches, if used, shall also permit safe manual operation.

105. Conductors

1. Electrical distribution shall use insulated stranded-copper conductors.(refer to Table 9.1) Conductor

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insulation shall be of fire-retardant material, (e.g. not supporting combustion in the absence of flame.)

2. Conductors that are not sheathed shall be supported throughout their length in conduits, cable trunk, or trays, or by individual supports at maximum intervals of 300 mm.

3. Sheathed conductors and battery conductors to the battery disconnect switch shall be supported at maximum intervals of 300 mm, with the first support not more than 1m from the terminal. Other

sheathed conductors shall be supported at board-non-sailing starter conductors constitute an

4. Conductors which may be exposed to physical

maximum intervals of 450 mm. Sheathed out- exception to this requirements.

damage shall be protected by sheaths, conduits or

other equivalent means. Conductors passing through bulkheads or structural members shall be pro- tected against damage to insulation by chafing.

5. Conductors shall have minimum dimensions in accordance with Table 9.1, or the conductor manu- facturer's rated current-carrying capacity, based on the load to be supplied and allowable voltage drop for the load to be carried. Conductors in voltage-critical circuits, such as starter non-sailing circuits, navigation-light circuits and ventilation-blower circuits, whose output may vary with system voltage, shall be sized in compliance with the component manufacturer's requirements. (refer to 102. 8 & 9)

6. Each conductor longer than 200 mm installed separately shall have an area of at least 1 mmË . Each conductor in a multi-conductor sheath shall have an area of at least 0.75 mmË and may extend out

of the sheath a distance not to exceeding 800 mm. An exception may be made for conductors of minimum area 0.75 mmË which may be used as internal wiring in panel-boards.

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

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

a.c. circuit by an earthed metal screen of equivalent current-carrying capacity to that of the larg- est core in either 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 d.c and a.c. conductors are fixed directly to a surface and separated by at least 100 mm.

8. Each electrical conductor that is part of the electrical system shall have a means to identify its function in the system, except for conductors integral with engines as supplied by their

manufacturers.

(1) All equipotential bonding conductors shall be identified by green, or green with a yellow stripe insulation, or may be uninsulated. Conductors with green, or green with a yellow stripe in- sulation shall not be used for current-carrying conductors.

(2) Means of identification other than colour for d.c. positive conductors is permitted if properly identified on the wiring diagram of the electrical system(s) of the craft.

(3) All d.c. negative conductors shall be identified by black or yellow insulation. If the craft is equipped with an a.c. electrical system (refer to ISO 13297) which may use black insulation

for live conductors, yellow insulation shall be used for d.c. negative conductors of the d.c.

system. Black or yellow insulation shall not be used for d.c. positive conductors.

(4) Insulation-temperature ratings of conductors 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 9.

(5) For additional conductor specifications, refer to ISO 6722-3 and ISO 6722-4.

(6) Current-carrying conductors of the d.c. system shall be routed above anticipated levels of bilge water and in other areas where water may accumulate, or at least 25 mm above the level at which the automatic bilge-pump switch activates. If conductors must be routed in the bilge area, the wiring and connections shall be in an IP 67 enclosure, in accordance with lEC 60529, as a minimum, and there shall be no connection below the foreseeable water level.

(7) Conductors shall be routed away from exhaust pipes and other heat sources which can damage the insulation. The minimum clearance of the conductors is 50 mm from water-cooled exhaust

components and 250 mm from dry exhaust components, unless an equivalent thermal barrier is

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provided.

9. Cross-sectional area of conductor, allowable continuous current and the number of strands for con- ductors are as follows.

(1) Cross-sectional area of conductor, allowable continuous current and stranding

Table 9.1 Cross-sectional area of conductor, allowable continuous current and stranding

(based on ambient temperature 30 ℃)

(2) Correction factors about temperature rating of conductors insulation in engine rooms

For conductors in engine rooms (60 ℃ ambient), the maximum current rating in Table 9.1

shall be derated by the factors listed below.

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106. Overcurrent protection

1. A manually reset trip-free circuit-breaker, or a fuse, shall be installed within 200 mm of the source of power for each circuit or conductor of the system or, if impractical, each conductor shall be contained within a protective covering, such as a sheathing conduit or cable trunking, for its entire length from the source of power to the circuit-breaker or fuse. The following constitute exceptions.

(1) The main power-feed circuit from the battery to an engine-cranking non-sailing, if sheathed or supported to protect against abrasion and contact with conductive surfaces. (refer to 105. 2)

(2) The main power-feed from the battery to the panel-board (switchboard), distribution panel or fuse block, if sheathed or supported to protect against abrasion and contact with conductive

surfaces. (refer to 105. 2)

If the fuse or circuit-breaker at the source of the supply conductor is sized to protect the small- est conductor in the circuit, only the fuse or circuit-breaker at the source is required.

2. The voltage rating of each fuse or circuit-breaker shall not be less than the nominal circuit voltage; the current rating shall not exceed the value for the conductor of smallest diameter in the circuit.

3. Output circuits of self-limiting generators and battery chargers do not require fuses or cir- cuit- breakers.

107. Panel-boards (switchboards)

1. Panel-boards (switchboards) shall be installed such that the control elements, indicating instruments, circuit-breakers and fuses are readily accessible. The terminal side shall be accessible.

2. Connections and components on panel-boards shall be in locations protected from the expected con- ditions in conformity with lEC 60529

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

- IP 55 as a minimum, if exposed to splashing water

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

3. Panel-boards (switchboards) shall be permanently marked with the nominal

4. Craft equipped with both direct current (d.c.) and alternating current (a.c.) electrical systems shall have their distribution from either separate panel-boards or a common one with a partition or other positive means provided to separate clearly the a.c. and d.c. sections from each other. Wiring dia- grams to identify circuits, components and conductors shall be included, with the craft.

108.

Wiring connection and terminals

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

2. 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.

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

4. Screw-clamp or screwless terminal blocks shall conform to IEC 60947-7-1(Low-voltage switchgear and controlgear - Part 7-1: Ancillary equipment - Terminal blocks for copper conductors). Other terminals shall be of the ring or self-locking captive-spade type, not dependent on screw or nut tightness alone for retention on the stud or screw. An exception is that friction-type connectors may

be used in circuits not exceeding 20 A if the connection does not separate force of 20 N.

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

6. Exposed shanks of terminals shall be protected against accidental shorting by barriers or sleeves, except for those in the grounding system.

7. Solderless crimp-on terminals and connectors shall be attached with the type

when subjected to a

the use of insulating of crimping tool de-

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signed for the termination used and for a connection meeting the following requirements.

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 con- nection, without separating.

Table 9.2 - Tensile values for connectors

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

109.

Receptacles/sockets

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

2. Receptacles/sockets installed in locations subject to rain, spray or splashing shall have a minimum protection of IP 55, in accordance with lEC 60529 when not in use, e.g. protected by a cover with an effective weatherproof seal.

3. Receptacles/sockets installed in areas subject to flooding or momentary submersion shall have a minimum protection of IP 67, in accordance with lEC 60529, including when in use with connect- ing plugs.

110. Electrically operated direct-current bilge pumps

1. General

(1) Bilge pumps shall be designed to operate continuously at 87.5 % of nominal voltage, i.e. 10.5 V for a 12 V system, 21 V for a 24 V system, up to their design voltage at the point within the range of performance recommended for the pump that results in the highest power consumption.

(2) Bilge pumps and devices used to convert bilge pumps to automatic operation shall be igni- tion-protected in accordance with the requirements of ISO 8846(protection against ignition of surrounding flammable gases) and shall meet the electrical requirements of ISO 10133(ex-

tra-low-voltage d.c. installations).

(3) Bilge pumps shall be rated in litres of water flow per minute or per hour at nominal voltage, at static pressures of 0 kPa, 10 kPa and 20 kPa, i.e. 0 m, 1 m and 2 m output lift, with 1.5

times the lift in a

smooth bore hose length of an inside diameter equal to the pump-outlet out-

side diameter fixed to the pump outlet.

(A) The pump rating and capacities shall be stated in the installation and operating instructions.

(B) The pump rating shall include the maximum output pressure and lift at which the pump ceases operation, i.e. the discharge of water.

(4) Bilge pumps shall be provided with means of fastening them to the craft independently and securely.

(5) Materials used in the construction of bilge pumps, which can be expected to come in contact with sea water, shall be

(A) selected or coated to be resistant to corrosion,

(B) galvanically compatible, and

(C) resistant to deterioration by bilge-cleaning agents and intermittent exposure to petrol(gaso- line), oil and diesel fuel.

(6) Submersible pumps shall be provided with a strainer or other means of preventing debris enter- ing the pump inlet. Inlet strainers and screens shall be designed such that they can cleaned.

(7) Installation and operating instructions shall be available for each bilge pump. An electrical dia-

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gram shall be provided. It shall identify each conductor and shall include the proper location of the control switch in the circuit and the bonding connection, if applicable. The recommended overcurrent protection for non-integrally protected bilge pumps shall be stated. Installation in- structions shall require remote-mounted pumps to be fitted with a strainer or other means of preventing debris from entering the pump inlet.

(8) Centrifugal and axial flow pumps shall be capable of operating dry at their design voltage for at least 7 hours without creating a fire hazard. Alternatively, a means integral with the pumps shall be provided to shut the pump off automatically to prevent a fire hazard.

(9) Positive or semi-positive displacement pumps, i.e. those in which the impeller may be in con- tinuous

contact with the housing when operating dry, shall be capable of operating dry for at least 5 min without damage to the impeller or housing and for at least 1 hour without creating a fire hazard. Alternatively, a means integral with the pumps shall be provided to shut the pump off

automatically to prevent a fire hazard. A label shall be provided cautioning against operating the pump dry for more than 1 min.

2. Electrical requirements

(1) Bilge pumps shall be of the two-wire type or ation, with both power (positive) and return housing and the pump housing.

(2) Conductors used for connection to the power

three-wire type if for manual or automatic oper- (negative) conductors insulated from the motor

supply shall be of stranded copper meeting the

size, current capacity and insulation requirements of ISO 10133.

(3) Submersible pumps shall have watertight electrical connections, IP 56 in accordance with lEC 60529. The use of a length of watertight electrical cable sealed at the pump connection is rec-

ommended, so that connections to the power supply may be made above the normal bilge-water level.

(4) Metallic parts of the pump housing that could be exposed to contact with bilge water and may become a source of stray current leakage shall have provisions for bonding conductor connections. However, pumps designed with a double-Insulated electrical system, requiring a break in two distinct insulation systems before electrical leakage can reach exposed metallic parts, do not require a bonding connection.

(5) Bilge pumps shall be protected against continuously locked rotor conditions by

(A) integral overcurrent protection, or

(B) overcurrent protection in the circuit of a size to protect the bilge-pump motor, or

(C) fbaeciengtecmapebraleturoefs siunsteaxinciensgs oopfer1a5t0io℃n ,wiatth aan laomckbeidenrtoteomr pfoerat7urheouorfs 6w0i℃tho,uat ngdenweirtahtoinugt esuvri-

dence of charring, burning or melting.

(6) Bilge pumps shall be capable of withstanding a d.c. voltage of 500 V for 1 minute without leakage in excess of 1 mA. The test voltage shall be applied between the current-carrying parts and the non-current-carrying metal parts. If the pump is internally earthed, the earth connection shall be broken in order to carry out this test.

(7) Bilge pumps designed for automatic operation shall be provided with an override switch to per- mit manual operation if the automatic operation fails.

111. Ignition protection

1. Electrical components installed in compartments which may contain explosive vapour and gases shall be ignition-protected in accordance with ISO 8846(protection against ignition of surrounding flammable gases). Compartments which may contain explosive gases are those containing, or which have open connections with compartments containing, such items as

(1) spark-ignition engines or their fuel tanks

(2) joints or fittings in fuel lines connecting spark-ignition engines with their fuel tanks

Open compartments having 0.34 mË of open area per cubic metre of compartment volume exposed to the open atmosphere outside the craft constitute an exception to this requirement.

2. Electrical components installed in certain compartments in the craft with liquefied petroleum gas (LPG) systems, such as lockers and housings containing LPG cylinders and pressure regulators, shall be ignition-protected (refer to ISO 8846) as required in ISO 10239(Small craft-Liquefied pe- troleum gas (LPG) systems)

3. Electrical fans shall be in accordance with the requirements of ISO 9097 and shall be ignition-pro-

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tected in accordance with the requirements of ISO 8846.

112. Test

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

(1) Continuity test of circuit, particularly ring and protective circuits.

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

113. Owner's manual

Instructions supplied by manufacturers of low voltage d.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 10133 Annex B