BCCs were either involved or should find my stupidity
amusing if not salutary.

>> Ordinary vaccum cleaners don't generate anywhere near .5 atmosphere.

I tried to use a vacuum cleaner on "blow" to drive an air line to help
me in patching  a pool liner that was near death and growing holes as
it rubbed against the underlying concrete. I found that it would push
air down maybe 2 feet and that I had to rise from the bottom to the
level; where I could get air and then go down again - still better
than using a snorkel etc.

In due course the liner died - my young son came home from school and
threw a dive stick into the pool. It hit the side and catalysed the
pending death. The liner ripped with a vast bang (I'm told) as about
60 tons of water settled into its new home. The pool was left with
maybe a foot of water in it. My son was sure he was in vast trouble -
when I got home I thought it was a great joke - liner death had been
overdue.

Now - DO NOT TRY THIS AT HOME !!! :-) - I can't believe I did this, I
can't believe I'm still alive [tm] ...

The vacuum was on the poolside. While preparing to remove the dead
liner, and knowing that it could not make anywhere near enough head to
push air down into the pool and as it was now well above pool level I
decided to see how far up the hose it would pull water to. I was
standing in the pool. Duh! Turned on vacuum. As expected it moaned and
laboured as it pulled a head of water to a small height and no
further. Then very suddenly, water shot up the hose into the machine
and it started to spray water out various orifices while still
running. I had visions of imminent death and left the pool asap. Water
is not "overly" conductive and the column of rising water would have
been the conduit to the pool water, which I'm sure would have been
bulk grounded very well. The water was probably chlorinated and had
other chemical in it. Even if mains current did flow into the pool I
would quite possibly have been OK as I would (perhaps) be  at a local
potential above ground but not have  a significant potential
difference between my legs. Murphy has ways of making theories like
that not work.

So, I didn't die, I had fun, I learned several new things, and the
vacuum got an internal wash.


             Russell
--=20
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