On 06/02/2016 01:52 PM, Mike Bushroe wrote:
> ... And of course consider lightning rods on the roof and above the tallest
> things (trees or antennas) on the property. No guarantee that ALL of that
> would have stopped such a close strike but I think it would have greatly
> reduced the damage, especially the collateral damage.
>
>
Hello Mike
We took a direct hit to the antenna... Thankfully, the antenna served as a
lightning rod.
When you have that high of a dI/dt, that close, the magnetic flux is going to
induce currents into every conductive-loop nearby. A voltage surge with a field
intensity of many kV/foot propagates outward from the point of strike and across
the ground.
I had a battery powered toy turn itself on when the strike hit... and so did one
of the neighbors. Both of these were just sitting on tables... not electrically
connected to anything.
While I didn't have a whole-house suppressor, the vast majority of my damage was
from induced currents in ethernet, audio, and video cables strung around the
house. The induced current in the copper line feeding the swamp cooler gave it a
big enough jolt to destroy the controller I made for it in the attic just below.
(A 1kV 0.1uF ceramic disk cap I had across a 12v rail was blow to little burnt
pieces)
I did have six computers survive and keep running without any damage at all. Two
more froze: one lost an ethernet card and the other a video card. Five of the
'unscathed" computers were racked up in a common rack with in-rack UPSs and surge
suppressor.
If either of the neighbors had had a whole-house suppressor or inductors on their
mains, it might have helped them.
--
KevinO
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