On  Thursday, 08 January, 2009 3:33 PM   Xiaofan wrote


> In my previous job, my colleague was involved in the development
> of the lightening barriers. I believe that Gas Discharge Tube was
> used along with other components.
> http://www.am.pepperl-fuchs.com/products/productsubfamily.jsp?division=PA&productsubfamily_id=1328
>
> Xiaofan

Thanks for the leads Xiaofan  ...  I should be able to recommend a 
protection device from that lot.

Because the communications line is located around the circumference of the 
dairy  ...  a length of over 60 metres   ...  should there be more than one 
of these devices  ...  or should one suffice?

Because of the nature of the damage, I'm assuming that the cause was because 
of voltage induced in the communications cable  ...  not by any spikes up 
the supply lines.

Regards,   Roger

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