Tuesday, 7 October 2014

Electrifying against terrorists

We're awaiting delivery of the components for a 150 metres electric fence. After a lot of research we've decided to go for a six strand fence running at 9000 volts. The energiser will deliver a 3 Joule shock. It needs to to be that powerful because some of the potential intruders resort to insulation to protect themselves. If we were protecting against a herd of elephants  it would only be 4000 volts. 

Government legislation requires we identify the electric fence by warning signs, but we don't necessarily have to use a notices in the first language of the intruders. It will need new permanent fence posts installed, stringing galvanised braided steel wire, wire tensioning, myriad insulators carefully placed and trimming back of stray vegetation to prevent shorting of the current. We'll also install a comprehensive electrical grounding scheme both through the earth and also on selected wires to ensure the electric shock load is delivered to an unwary invader.

We had a break-in last winter through an insecure fence at our remote site. After a ram raid the intruders did a lot of damage, but once we were alerted we were able to drive them away from our property. We restored the fences and it kept the intruders at bay.  The local police were not interested. The electric fence will present an additional layer of security and deterrence to keep these cunning intruders at bay. The intruders are of course sheep from a neighbouring field trying to raid our orchard when our winter grass looks more attractive than their field. 

The fence will protect our investment in recently planted fruit trees and also a hedge recently relayed in a the traditional manner (expensive). Protecting the hedge for a couple of years will allow it to regrow the natural defence of sharp thorns and intertwined branches.

The set-up cost, excluding labour, is only £5/metre or approx $3/foot of fence. Extending the fence costs less than £1 a metre. Planning the installation was quite a useful refresher course on planning for security situations where deterrence is required for human intruders. 

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