[PSUBS-MAILIST] G.L. Rules Electrical Equipment Part 1

[Alan James]

Sorry I'm going to short change you in this summary. I am just covering the electrical rules for submersibles which are an adjunct & take priority over the G.L. rules "Electrical Installations," (190 pages), which  cover all sea going ships. If you know how to design your 1 person submersible to G.L. electrical standards, you should be able to do the same for a 480 meter long super tanker.
   The materials used in construction of electrical machines, cables & apparatus are to be resistant to moist & salty sea air, seawater & oil vapors. They aren't allowed to be hygroscopic & have to be flame resistant & self-extinguishing.
   Materials with high tracking resistance are to be used to support live parts.
   Pressure hull wall penetrators, underwater plug connectors & appliances directly connected to bus bars are designed for the next higher nominal insulation rating.
   Materials & insulation for electrical equipment used in water are assessed case by case.
   Networks with earthed neutrals aren't permitted.
Max of 50 volts for mobile appliances used in confined or damp spaces. 
   Chapter 2 section 11 B provides IP rating requirements for various electrical equipment. This section also provides dimensional rules for protective conductors.
   All electrical equipment essential for the safety of the submersible & it's crew is to be connected to 
an independent main & emergency power supply system.
   The main power source has to consist of at least 2 mutually independent, redundant power generating systems. Exceptions may be permitted for vehicles with restricted range of service or
accompanied by a support ship. I am not sure whether this means that if you have a 24V system,
that you could have 2 banks of 24V & draw from them simultaneously or 1 bank at a time if required.
To be continued.....
Alan
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