Fundamentals of Electric Fencing    

The most effective
perimeter security
anyone can have.


Just like anything else one can buy, there is a wide range of quality on the market. Poor quality normally equates to cheap. But consider this – cheap also means unreliable, which costs money to repair. It will also have a far shorter lifespan and will require replacing components earlier. It is dangerous on two fronts – false alarming causes complacency (when the alarm sounds, the homeowner assumes it’s not from a true threat and does not take appropriate action) and it offers an ineffective barrier (that criminals can penetrate with ease). And any company that offers cheap equipment will undoubtedly offer a substandard installation and back-up service. In a nutshell – poor quality equipment costs far more in the long run and is ineffective.

A good example (of what we offer) is the JVA z range energizers. Take the JVA Z14 for example. It’s a 4 Jule machine, but that is the Jules that it actually pushes out onto the fence (it has 6 Jules stored in the energizer). Cheaper brands have 4 Jules stored and push out below 3 jules onto the fence (but they are sold as 4 jule energizers!). The JVA’s are extremely reliable and sophisticated. They carry a 2 year guarantee and parts are readily available. We have aligned ourselves with the JVA brand of energizers because they offer high end features, they rarely break down, repairs are quick and costs are reasonable, and the operating costs are low.

Basic equipment for an average installation:

  • Energizer (converts electricity into legal format)
  • Backup battery (if mains power is down)
  • Siren
  • Lightning Diverter Kit
  • Electric fence (wall-top or freestanding)
  • Keypad or Remote/Receiver (to turn system on/off)
  • Nite Lite (LED lights in fence that flash indicating on/off)
  • Semi-Industrial Gate Contact (sliding gates only)
  • Conduit and cable
  • COC certificate

The energizer is most commonly installed in a garage/outbuilding as is does emit a ticking sound (similar to a wall clock) that can be annoying. It can also be housed in a weather-proof box and installed outdoors. We do require a standard plug point for the energizer. Energizers have a standard on/off key on the casing but most customers order a receiver and 2 remotes for convenience and safety. The lightning diverter kit is a legal requirement and is usually installed near to the fence circuit start point.


How the fence is installed is as critical as the equipment used. A good installer is an experienced installer and needs to understand how a criminal thinks. Our staff are able to stand across the road from any property with an electric fence (not ours!) and can, the vast majority of times, point out several weak points that can offer easy access to an intruder. The average roadside electric fence has several access points and criminals take seconds to identify them.

Our philosophy is simple – install the fence in such a way that when a criminal surveys the property for a discreet entry point he quickly realizes that there aren’t any! (and he looks elsewhere for a softer target). The brutal truth is that your security needs to be noticeably higher/more sophisticated than the properties in your vicinity (the hardest target in the area).

At ASF, our installation techniques are far higher than what is recommended as industry good practice as well as the legal requirements. We have in-house staff with COC certification and all our fences are issued with a certificate.

How Electric Fencing Works

Electric fences are designed to create an electrical circuit when touched by a person. An energizer converts power into a brief high voltage pulse. One terminal of the power energizer releases an electrical pulse along a connected bare wire about once per second. Another terminal is connected to a metal rod implanted in the earth, called an earth spike. A person touching both the wire and the earth during a pulse will complete an electrical circuit and will conduct the pulse, causing an electric shock.

The fence will go to alarm if: The fence is earthed for 3 pulses/seconds (shocks someone/something) OR if a live wire and an earth wire make contact for more than 3 seconds OR of a live wire is cut.

The siren would then sound. Most customers have their security company/provider monitor the energizer (just like a home alarm system is monitored).

The system would now need to be re-set by simply turning it off and then on again. This can be done from the safety of your bedroom with the remote.

Electric fencing is only turned off for maintenance (eg. cutting back plants) or for servicing and its electricity consumption is below R20.00/month. The battery back-up offers approximately 8 hours of operation at full function.

Specs and Features

 Inherently stable system (unlike beams)

 Extremely effective

 Is a self contained alarm system (includes a siren)

 Can be linked to your security company

 Operates 24/7 (turned off only for maintenance)

 Highly adaptable

 Low running cost (approximately R20/month)

 Low maintenance (vegetation needs to be kept clear)

 Safe (non-lethal and no permanent damage from a shock)

 Long battery back-up is standard equipment(for load shedding/power cuts)

 Aesthetically pleasing (not highly noticeable)