Lightining

[Eric Oyen]

wow,
this almost looks like a ham radio discussion list with this topic (btw, we hams also have need to protect sensitive gear). I will have to dig up a publication online. I think the ARRL has it. It details ways to save your equipment from all these hassles and also reduce noise (some kinds of noise can adversely affect how computer equipment operates).

-eric

On Jun 2, 2016, at 4:25 PM, KevinO wrote:

> 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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