dpb wrote:

Could be charging blocking cap and is causing some. Or perhaps the
reversing polarity is discharging a cap when into the neutral which is
at ground.
Doubtful. The caps are so small. Getting sparks when plugging in a VOM
means something really wrong. Either a short in the meter or on
something like the 10 amp scale.

My bet is w/ the likelihood you were either on a continuity or current
or input range by accident.
Agree




Except for the floating ground introduced w/ the use of a grounding
outlet w/ a two-wire service, there really isn't anything so
bad-sounding on the house here except it sounds like there might be
crossed neutrals and hots if the receptacles weren't installed
correctly (or at least consistently). I'd do a certainty check on that
for all of them and I'd do it visually rather than relying on an
inexpensive tester -- I've seen cases where some weren't terribly
reliable.

And even if they are crossed it should make no difference for most
appliances. Danger is that some things such as lamps could end up with
the outside being hot. But even they are insulated. In the old days
you could end up with a radio chassis being hot. No polarization at all
in those days either.