[PSUBS-MAILIST] G.L. Rules Electrical Equipment Part 2

[Alan James]

   The emergency power supply has to be adequate to simultaneously supply
any electrical system needed for surfacing plus emergency lighting, emergency 
communications equipment, life support equipment, essential monitoring & alarm
equipment such as fire alarm system, breathing air monitoring, H2 monitoring,
locating equipment & signal lamps.
   For charging there needs to be an indicator on the main switchboard to show whether 
the shore connection line is live.
   The batteries have to be sufficient for the mission when charged to 80% ( that's how I
interpret it)
   All equipment running off batteries has to be able to operate at a voltage
of 25% (30% if operating while charging) above normal voltage or 25% below.
It looks like they require the battery voltage to be above the lower limits in the above

paragraph, at the end of your day. I got a bit lost here, they refer you to GL rules for ships
electrical installations (1-1-3), section 1, F. & section 3, C.
   Batteries aren't allowed to leak at angles of up to 45 degrees.
   Where the battery capacity is 1000 Ah or more the battery is to be divided in to smaller units
so that in the event of a fault there is still some operational ability.
   The use of rigid interconnection links between batteries is to be avoided.
   The rating data of the battery is to be indicated on "rating plates".
   The weight of the biggest battery can't exceed 100kg.
   Electrical distribution systems are to be designed so that a fault in one circuit can't impair
the operation of another circuit or the power supply.
   Circuits at protective low voltage aren't allowed to be routed with higher voltage circuits in
a joint conductor bundle or cable duct.
   All consumer circuits are to be fitted with switches. The switching action has to be on all poles.
   Fuses may be used for overload protection up to a rated current of 63 A ??? don't know whether 
this includes circuit breakers, seems a bit low.
   A continuously operating insulation monitoring system is to be installed with an alarm on the control
stand that is tripped if the insulation value drops below a preset limit. (in general 50ohm for 1V)
   Electrical enclosures outside the hull are to be G.L. approved.
   There is a chart for the selection & dimensioning of wires in the electrical rules for ships 1-1-3 section 12.
   Only halogen free materials are to be used in wire insulations.
   Bus bar temperatures aren't allowed to exceed 100 C.
   Where bus bars are used for connecting equipment only sealed or insulated systems may be employed.
This does not include switchboards & enclosed electrical service spaces.
   Pressure hull penetrations are to be gas & watertight, even if they are damaged or shorn off. ( there goes the
blue globe cable glands)
   The positive & negative conductors from a power source aren't allowed to pass through the same hull penetration.
   Electrical conductors within the penetrating device shall be of solid material.
   The minimum insulation resistance is 5 MOhm for the type test.
Alan
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