[TowerTalk] TowerTalk Digest, Vol 127, Issue 27

[David Robbins]

actually.... you can have great grounding and still get this kind of damage if you don't equalize the incoming line voltage with ground at the entrance.  most of this damage was probably from what is called a back flashover.  this is where the ground potential changes relative to the power/signal wires due to a lightning strike to a tower or ground or power line ground.  in these cases the power/signal wires can be looked at as being at a constant voltage while the ground potential changes until it flashes over to the signal wire, in the case of homes this is often through your equipment power supply or modem on a phone line or cable tv box.  the fix for this is to apply mov's or other voltage equalizers between the power/signal lines to ground at your service entrance/single point ground so all the wires rise and fall at the same time.

Low voltage stuff can still be damaged by another factor, induced currents from nearby strikes.  the longer the wiring attached to the device the higher the voltage.  preventing this type of damage requires mov or other equalizer on devices inside if they don't have them built in.  this is where surge arresters in power strips or ups's can help out since the energy is 'relatively' small compared to other events.


Jul 11, 2013 08:38:26 AM, nn4x at embarqmail.com wrote:

Skip -

Lighting protection is science, not religion, and requires no "belief".

Consider that tall buildings, towers, the electrical grid, and aircraft, 
among many other things, are routinely hit by lightning and survive 
unscathed.

Clearly, the lighting damage you and your neighbors experienced was due 
to insufficient grounding.

73,
Steve
NN4X


>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 10 Jul 2013 12:28:13 -0400
> From: "Skip K3CC"
> To:
> Subject: Re: [TowerTalk] lightening strike
> Message-ID: <1799C47B78784951BBB6AE974178086C at k3ccPC>
> Content-Type: text/plain; charset="iso-8859-1"
>
> I have had one very bad lightening strike that I lost almost all
> the appliance's connected to the electrical service.
> THey included, hot water heater, cook stove, freezer, dishwasher
> my entire radio station, computers , TV, Stereo ETC. You get the picture.
>
> The strike was a ground strike that came in through the ground system of the
> electrical panel and phone line.
> This strike took out 4 homes and all the under ground utilities had to be replaced.
>
> I have never believed in any kind of lightening protection. I used to live on top of
> a hill at 1200 ft. I now live in a 20 acres field at 2300 ft. How can you protect against
> a strike through the grounding system ????
>
> de Skip
> Skip Kauffman
> ARS K3CC
> EC ARES Potter CO, PA
> www.k3cc.net 
>
>

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