quote from another post....
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"You don't have a clue how lucky you are! Serious. I went to a
Lightning
engineering course at Poly Phaser in Nevada for 7 days to study the
effects
of lightning and what paths are travelled. If that longwire was only
50'
from where your wire was, you are damned lucky!"

"The damage that you mentioned is not from a line getting struck, but
rather
from the ground suddenly becoming an above ground source.... In other
words,
the "Ground" that everything else in the house is attached to started
raising to a potential of 1000 - 50,000 volts. The damage occurs when
the
telephone, cable, electrical and all of the other lines still stay at
their
same normal potential.... 110 volts, 24 volts and cable TV ground....
So,
you see the problem. The 1000 - 50,000 volt charge tries to escape
through
the little life lines to your house. So............ BOOM! IF that
would have
come down your longwire and into your headphones, I as well as your
family
would be very very upset right now. So, you are one lucky guy!"

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This is the post I was referring to as far as differences in ground
potential.
If all the grounds had been tied together, and at the same potential,
this would not have happened. This is the main reason why I could
never advocate separate grounds. It's inviting disaster. MK