On 5/28/05, Russell McMahon <apptech@paradise.net.nz> wrote:
> >>I still have a problem with my protection to the circuit.
> 
> Completely opto isolating the input circuitry from the processing 
> curcuitry with a coupler (possibly home made) rated at 10's of 
> kilovolts will help greatly and not cost much relative to everything 
> else involved.

  "VERY" agree ! But keep the input circuit into optoisolator supplied
from one accumulator, else the isolation is in vain. 25KV is minimum
range.
Test the homebrew optoisolator for leackage current at 10-20KV ac.

  Vasile

> 
> Where the cable leaves the fence in an insulated pair (or more) of 
> wires, run it down to ground level and wind the cable in a two or 
> three turn loop of around 150mm diameter with the bottom of the coil 
> touching the ground or even partially buried in it. A full lightning 
> strike will burn through to ground at this point. Mathematical 
> calculations show that a coil like this is not an effective bar to 
> lightning BUT practical experience shows that it works. You still have 
> to deal with a very nasty spike on the line beyond this point but it 
> "takes the edge off it".  I don;t think anyone mentioned gaseous 
> arrestors (gas discharge tubes) which are specially made for lightning 
> protection and are arguably THE most effective means available of 
> limiting lightning potential rise. Google will know about them.
> 
> 
> 
> 
>         RM 
> 
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