[PSUBS-MAILIST] DNVGL

[River Dolfi via Personal_Submersibles]

Scott and I have been driving ourselves crazy trying to interpret the DNVGL
rules on subsea electrical cables. We think that the essence of the problem
is that DNVGL lacks rules specific to oil-compensated external battery
banks (except being subject to "approval by the society"), and to the best
of our knowledge DNVGL has yet to certify any submersible with external
ambient batteries.

One rule in particular is making us scratch our heads. UWT pt4 ch8 sec2-1.3
states that "All cables in the outer area shall comply with (cargo ship
cable rules section). All cables shall have an EARTHED braiding or screen
around the conductors and be equipped with an insulating outer sheet." If
this is applicable to the main battery cable, damage could potentially
create an incredibly dangerous ground fault condition where high voltage is
passed to the sphere. While this requirement makes sense for low-voltage
electronics who require protection from electromagnetic interference, it
appears to be nonsense when applied to a high-voltage DC power cable.

Thanks,

-River J. Dolfi
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