110.40 90c terms /reference to tables for ampacity. MV Cables.

Cables going underwater ? No table for that!

Article 328 MV Cable uses permitted (#1 Wet Location??)

There are cables rated for underwater.

Seems like code needs to catch up.

Are 15 KV dead break elbows rated 105 c or 90c ( For rating of conductor Ampacity?)

FPL ran a couple miles of this stuff under the Estero Bay.
As for ampacity it will certainly be as good as free air.
Water will actually take the heat away faster.