In article aqZwi.10204$Ns6.6028@trnddc01,
Robert Allison wrote:

I built a lake home for some clients and later installed an
underground drop to a pedestal with a 240 volt disconnect
(exactly like an AC disconnect). From there, the people who
built the dock tied into the disconnect to run wire out to the
dock.

Then the rains came. The lake rose almost 35 feet in a matter
of weeks. More rain. The lake rose to flood stage and
submerged the pedestal. Yet power remained to the dock. The
pedestal was under about 15' of water, yet did not trip the
breaker at the main service. The owner called me and asked if
this was dangerous and I said yes, turn off the breaker at the
breaker box, which he did.

My question is: why did the breaker not trip when the
disconnect was submerged? It is not waterproof by any means.

It's probably one of those new-fangled distilled water lakes that the
military is experimenting with.