[TowerTalk] My situation: Is lightning protection needed?

[K8RI]

On 7/10/2013 10:29 AM, Art Greenberg wrote:
> The discussion about protecting networked computers is of interest to me
> because I have been thinking about an application here. I thought I'd
> start a new thread about my particular situation to see what others think.
>
> I have an enclosed, air conditioned barn that I'd like to put my shack
> in. The thinking is, I'd run an Ethernet cable to the house using an
> existing buried conduit (that is now empty) and run the radio equipment
> remotely. The conduit run is about 230 feet. I figure a total run of 300
> feet or so to connect a switch in the barn to a switch in the house. Our
> Internet service comes into the house.

Being in FL the ground is probably dry, even if it gets soaked a couple 
time a day. (Been there)

Using Cat 6, I'm using 2 runs of 130 feet with 9, 90 degree bends in PVC 
conduit running a gigabit network that is about 200 feet from end to end.

"Supposedly" you can get up to 300 feet, but that is one of those 
misleading statements where the key is the phrase "up to".  Even 130 
feet gets a bit fussy with bends "without kinks".


IF you can make it work, I'd want lightning protection on each end.  I 
know, most of it is in conduit, run underground but two buildings that 
far apart AND on separate feeds (different transformers?) can be many 
thousands of volts apart just with a nearby strike. Although partially 
protected by being underground, if the soil is dry sand you will have no 
where near the protection we have up here with wet, heavy clay.

You have a lot of negatives:  A long run, near the limit for Cat6
You will have over 200 feet of copper wire between two different 
services in a lightening prone area

I don't know that much about fiber even though my field and degree are 
in CS. (I graduated in 1990)  I'd really like to change to fiber for my 
whole network.


73

Roger (K8RI)

>
> The barn has its own electric service. There is a shunt-mode "whole
> house" surge arrestor installed in the load center. The service feeder
> to the barn and the service feeder to the house come from completely
> different directions. Both are above ground until they get close.
>
> The antenna transmission lines to the barn would all be run through an
> entrance panel with lightning arrestors, bonded to the barn's service
> ground. All of the radio equipment would be grounded to the entrance
> panel ground. The radio equipment would be very close to the load center.
>
> If I can get a reliable gigabit network running between the barn and the
> house, I could put some of my other computer equipment in the barn as well.
>
> I'm in Florida, near Gainesville. Lots of lighthing, particularly during
> summer.
>
> Long prologue. Now the question.
>
> I think its obvious that fiber would provide complete isolation between
> the buildings. But would a copper cable (Cat5e, Cat6) with lightning
> arrestors at each end be good enough? What strike scenarios would be
> problematic?
>
> Thanks all.
>
> --
> Art Greenberg
> WA2LLN
> art at artg.tv
>
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