A challenge facing both existing and potentially new perimeter electric fence installations is how to economically meet the legal requirements required in clauses 4.8.2, 9.4, and 9.7 of the SANS 10222-3:2016 standards document referred to in the new Act. These clauses relate to the protection of the general public from being accidently shocked by an electric security fence.
These clauses require one to erect an expensive barrier fence in front of an electric fence to protect the general public from making inadvertent or accidental contact with the fence and thus receiving a shock. A solution to overcome this expensive option economically is to install JVA low voltage monitors along those portions of the fence-line requiring protection from the public.
Let us start by looking at the relevant clauses referred to in the Act, their interpretation, and their purpose:
Clause 220.127.116.11 states: “No electric fence shall be installed in a public area unless the first live conductor’s minimum height is 1500 mm above walking or ground level (or both) or is covered by a barrier fence from the public area with a minimum height of 1500 mm….”
Quite simply, this means that one may not have any high-powered electric fence wires below a height of 1500 mm, be it for a wall-top or free-standing electric fence and, if you do, you must have a barrier fence in front of these live wires. This is to prevent the general public, and in particular, small children, from making accidental contact with the fence and being shocked.
Clause 18.104.22.168 states, “The minimum distance between an electric fence and a building element or barrier fence (or both) shall be less than 200 mm or greater than 1000 mm.”
This means that your barrier fence has to be closer than 200 mm or further than 1000 mm away from the electric fence. Why? Simply to avoid entrapment between the electric fence and the barrier fence. One can’t fit between 200 mm away barrier fence and the electric fence or alternatively one has enough space to move between the barrier and the electric fence if it is over a metre away.
Clause 22.214.171.124 states, “The building element or barrier fence next to an electric fence (or both) shall have one dimension of the opening not greater than 150 mm.”
This means that one can use palisade fencing as the barrier fence as long as the panels of the palisade are no more than 150 mm apart. Alternatively, one can reinforce an existing palisade fence with electric wires as long as the panels are no more than 150 mm apart. Once again, the public is protected.
9.7. Barrier fences
Clause 9.7 states: “Barrier fences shall have
a) A minimum height of 1500 mm, and
b) One dimension of the opening not greater than 150 mm”.
Again, for protection. One can’t simply stretch over the barrier fence and touch the electric fence, nor can one accidently blunder into it. However, clause 4.8.2. then states, “… the minimum height of the barrier fence can be reduced to 1.2 m provided the barrier is erected more than 1.5 m from the electric fence. The barrier fence shall comply with 126.96.36.199.”
This clause effectively means that people in rural areas (farmers in particular) need not install a barrier fence next to their homestead electric security fence because the farm is ring fenced by a 1.2 m fence which is more than 1.5 m away from the electric fence. Anyone within this area is not regarded as general public and if they are there without permission they are trespassing.
How to adhere to the law
This brings us to the question of how to meet these legal requirements. There are two scenarios that need to be covered, both of which require a COC. A COC is a Certificate of Compliance that certifies that the fence meets legal requirements. The two scenarios are: a homeowner with a property which is for sale, with an existing electric fence around it, which will need to produce a COC at completion and handover; and any new security electric fence erected after 1 October 2012 will also require a COC.
In the first scenario above, one has two options: the first option is to erect a barrier fence in accordance with the legislation. This is an expensive option. A further problem encountered with many existing installations’ electric security fences is that they have been erected right on the property’s boundary, so there is no room to erect an expensive barrier fence, even if the owner wishes to do so.
In this case, the simplest solution is to reconfigure the fence so that the bottom 1500 mm is still monitored but now, by using JVA’S low voltage technology while the upper portion above 1500 mm retains its high voltage shock and monitoring ability. This option will obviously remove the deterrent shock off that portion of the fence, but it will still be monitored and will still retain a visual psychological deterrence.
When it comes to the erection of new, free-standing fences, one can simply repeat the above and power the bottom 1500 mm portion of the fence lines using a JVA ZLM4 low-voltage monitoring system and again have the top portion wired for high-voltage monitoring – a simple, economical and effective solution. One could also further improve the sensitivity of the fence by including a taught-wire monitoring system into this design.
Low-voltage compared to reduced-voltage
A question often asked is what exactly is low-voltage monitoring compared to reduced-voltage monitoring and how come this low-voltage monitoring makes the fence legal? According to Clause 3.30 of SANS 10222-3-2016: ‘High tension electric fencing – where the peak voltage of the pulsed system exceeds 50 V d.c. or a.c. (r.m.s.)”. A JVA LM4 meets this requirement by emitting a monitored pulse of less than 50 volts. By definition it is therefore not a high-tension electric fence and it is therefore completely legal.
On the other hand, reduced-voltage fencing is simply a high-powered energiser that has had its output voltage reduced by means of applying resistors and these generally operate at around 600 volts making it still a high-tension electric fence and therefore illegal.
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