Oh yes. Gas arrestors are one of the best device for lighten 
protection. The company I am working for have lots of 
Over-voltage suppressor (lightning-protection barrier).

Take a look at my company's web site.
http://www.pepperl-fuchs.com and search for P-LB and K-LB.
The discharge current is up to 10KA.

Xiaofan

-----Original Message-----
From: Russell McMahon [mailto:apptech@paradise.net.nz]
Sent: Saturday, May 28, 2005 11:07 PM
To: Microcontroller discussion list - Public.
Subject: Re: [PIC] Pin Protection

>>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.

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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