Rick, you don't mention the deep submersibles method of routing nearly all
electrical cables inside of tygon tubing and fittings and filled with
mineral oil. The fluid is always at the same pressure as the water outside..
If everything goes as planned, the cabling is never exposed to seawater,
even at 10,000 ft.

I have built and repaired hundreds of cable assemblies for the DSVs and the
DSRVs while working for Locheed Advanced Marine Systems.

Steve
s/v Good Intentions