© Intelligent Fencing Systems, Inc. 2006-2011 Brandon, Florida 1-813-315-8082

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

---

 

GENERAL DESCRIPTION AND INSTALLATION

There are several basic considerations and many secondary considerations in designing an electric fence. We shall discuss the primary considerations first.

NOTE:  When properly designed and installed, an electric perimeter security fence is the least expensive, safest, and most secure method for securing the perimeter of a property and lives when compared to walls, other types of fences, human guards, and watch dogs. The fence does NOT sleep. The fence CANNOT be bribed. The fence does NOT require food or water. A well designed electric perimeter fence has more deterrence value than a guard with a sawed off shotgun or a snarling pit bull, Either a fence alarm or electric fence alarm is a critical component. Few to zero people will touch a live electric fence, however, and electric fence is relatively easy to short out and remove the voltage involved and this is why in combination with; a fence monitor, or electric fence alarm, or just a plain fence alarm, with voltage alarm capabilities is required to make a secure electric fence. The trespasser or intruder may cut or short the fence, however, will not be able to do this without setting off the alarm. Our Electric Fence Companion with Weed Alert is the best on the market for this purpose. The Weed Alert feature lets you know when  the weeds and brush are starting to affect the operation of your fence. This is a very accurate measurement and can be adjusted for any fence energizer, or fence charger (fencer). When the fence conductor is cut, the voltage on the fence is dropped off, and the alarm responds .... There is NO way an intruder can pass through or over a well designed electric fence that is using the Electric Fence Companion. The Electric Fence Companion turns a ordinary electric fence into a high security electric fence. This is the best of both worlds ... With a fence alarm or electric fence alarm, especially with the "Weed Alert" feature, your nights turn into peaceful sleepy evenings.

1. COST:  Please consider that any cost is “too expensive” if the perimeter  fence is ineffectual, or just doesn’t work. So then, we have to have a minimally effective design, to justify the cost, or it isn’t worth doing at all. Do it right, or don't bother. There are many design suggestions of different types of Perimeter Electric Fence solutions within this web-site.

If you have security guards, you can pay for the perimeter fence (justify) by laying off at least half of your guard force and still maintain a much higher security level. The remaining guards can respond quickly before an intruder even enters onto the property.  

   An Electric Perimeter Security Fence is designed to keep out predators, thieves, trespassers, vandals and disease. If you also employ security guards, they will complement the security that is provided by a well designed high voltage electric fence perimeter.

   An Electric Fence Secure Perimeter is designed to protect property, livestock, production, manufacturing, and lives. We have the electric fence supplies that are hard to find and make a secure electric fence. We don't try to compete with specialty stores selling electric fence supplies, but concentrate around the needs of a secure perimeter.

   There is literally no way one can penetrate or pass through a well designed high voltage perimeter fence without setting off the electric fence alarm. This electric fence alarm or electronic fence alarm will sense and monitor the fence voltage and will sound a low voltage alarm if the fence voltage is starting to be reduced by weeds or brush. It will absolutely sound a no voltage alarm if the fence conductor is cut or shorted. In any case, when the voltage drops below a certain level, the different alarms will sound.

   When designing your electric perimeter security fence, keep in mind the above two statements and each individual item that applies. Also to “keep out” or to “keep in” or “both” are all valid considerations.

   The smallest effective “fence extension” consists of 3 strands where one (1) center strand is grounded (ground potential) and a minimum of two (2) charged strands. The reason for 2 charged strands is security. You make the connections to achieve one (1) charged wire where the high voltage goes out and then loops to return on the second strand. 

   However, if you connect both the outgoing and returning ends to the charger, then, even if cut, the high tensile wire is charged from both ends. 

   The more secure design is, the returning high tensile wire is connected to a high voltage monitor and alarm.

   Therefore all electric security fences should have an even number of charged “high tensile” strands. 2, 4, 6, 8, etc. strands.

   A voltage sensing monitor attached to the very end of the charged strand will sound and alarm or siren if the wire is cut or shorted making the voltage drop. Although very few petty thieves will attempt to cut through the fence, the fence/voltage sensing monitor makes the electric security fence perimeter into an alarm sounding security device when tampered with. 

   If the perimeter fence is designed to make it very difficult to pass without a resultant shock, and when coupled with a voltage sensing fence monitor becomes an extremely effective security system. The final determination will always be a balance to whether the additional level of security is worth the added cost of a voltage sensing monitor alarm.

   Grounded Strands: the high tensile strands should alternate with grounded strands. The grounded strands should be insulated exactly like the high tensile strands. If all the strands are insulated, the fence is perceived as much more lethal, and therefore becomes much more effective. If an intruder actually decides to cut a wire, not knowing which are grounded strands and which are charged strands makes the fence retain a higher security rating.

   A perimeter fence is designed with 3 or more strands. Usually, the top strand and the bottom strand are charged, however, there are some cases where a 4th grounded strand is added as the topmost strand to help ward of falling foliage, fronds, etc to help prevent the plants from shorting out the high tensile strands and creating "false alarms". 

   If the perimeter electric fence is constructed from ground level, then the bottom strand may be a grounded strand to prevent weeds and grass from shorting out the “high tensile” circuit. However, a concrete footer is a better design option.

(goto MAIN MENU)

INSTALLING THE EQUIPMENT:


   The components of your system should be installed and mounted inside and out of sight and LOCKED out of reach from unauthorized people. Hang the high voltage charger from the wall and connect it to the battery placed under fence charger using the red and black wires that are attached to the fence charger with the red wire to the positive terminal and the black wire to the negative terminal.

NOTE: Make sure the fence charger switch is turned to the “OFF” position. Connect the battery charger to the battery and plug the battery charger into the wall voltage of 230 volts so that the battery is being continuously charged. The current limiting circuit supplied with the charger will keep the battery from becoming over-charged and protect the charger from shorts.

   Now connect your Earth Ground System  and all your ground return wires together, and then make the connection to ground connection on the fence charger. Use a minimum sized wire of 14 AWG or larger, in either solid copper or galvanized steel and make the connections with appropriate connectors. A common cause of failure is a poor connection to the high voltage strands from the high voltage charger.

   Finally make your high voltage connection to the fence using an appropriate connector with high tensile or spark plug wire with an insulation rating of 15,000 volts or higher. When you run the high tensile wire to the fence charger make sure the high voltage wire is not laying on the ground, and is not running through water, and is not placed across sharp corners. Many installations use standard (14AWG solid) single strand wire fed through a thick wall plastic hose.

   If you have purchased a fence monitor connect it to your battery and connect the high voltage input to the high voltage terminal on the monitor using the same high tensile wire that you used to connect the charger to the fence. Connect the Earth Ground System to the ground terminal of the monitor.

   The fence monitor will continuously monitor the voltage on the fence. If an intruder cuts a wire the fence monitor will sound a siren alarm.

   As the monitor is powered from the same battery that feeds the charger, and the "fail safe" relay will close on loss of High Voltage, the relay will also close on the loss of the 12 volts from the battery that is powering both the charger and the monitor, so we strongly recommend a separate battery that powers the siren, bell, or whatever alarm notification is provided. The small extra cost of a small 12 volt battery that will feed your siren raises the security rating of your system at least another notch higher on the security rating scale.

   The built-in voltmeter on the High Voltage charger also continuously monitors the voltage on the fence. If a frond or foliage is laying across the high tensile wire, and partially shorting it out, the fence voltage will drop. If the voltage drops out of the green zone, it is time to clean your fence.

   We recommend that you check your fence at least once a week. Plant foliage, or branches or fronds laying across the high tensile wire might not reduce the voltage on the meter when dry, but foliage becomes a conductor when wet and might easily short out your system completely reducing the fence voltage to almost zero when soaked from rain.

BASIC DESIGN CONSIDERATIONS 

EFFECTIVENESS:  When considering the design of the electric security fence perimeter, look around at what is already being used. The coiled barbed wire and barbed wire strands that top off most fences are meant to look hurtful and difficult to get over and around. Also the broken glass that is embedded on the top of many walls needs to be plainly visible to be truly effective, and works because it is visible and makes it more difficult for a trespasser to scale the wall, so that hopefully the trespasser will bypass this property and pick another house or property to break into, where it is easier to gain access.

   A wall or fence is just a device that defines your perimeter property line, and sometimes provides some privacy. Any wall or fence can be easily scaled. And if you make the walls higher, the intruder uses a pole or ladder or tree and climbs over. There are many ways that even a very high wall can be scaled and breached. 

   Dogs are one of the better methods that will provide an alarm. However if the dog is tied or caged, then it is only able to provide noise, which is effective only if someone is there to hear the barking. Dogs can be poisoned; require care, feeding and sleep. In contrast, an electric security fence deters someone from even trying to trespass and is actually more effective than a 15 meter high wall and never sleeps and can provide noise if tampered with.

   When a thief or trespasser picks a house or property to rob, they will invariably pick a target that is easy to gain access to, and they will pick a target that offers the least risk and exposure to themselves. A well designed electric security fence will virtually eliminate all petty theft and trespassers. They won’t even try to gain access.

NOTE:  The primary object of an electric security fence is NOT to shock the intruder or trespasser in the process of scaling your fence or wall, but to persuade the intruder that it is not worth the trouble to try to get onto your property in the first place. Let the thief go to another house that is an easier target for him. 

   Stop the intruder from trying to trespass onto your property before he even attempts. If he suspects that your fence is a bluff, a very few might touch the charged wires and the resultant shock will completely convince them otherwise. Even if the trespasser suspects that the voltage is “non-lethal” he will not be sure, and he will be quick to try a different property. This is why “the lethal look” of the fence is just as, and even more important than the fact that the fence is actually charged. People are scared of electricity. People can’t see electricity. If people perceive that the fence is dangerous, then it becomes effective.

 Every municipal ordinance that is available for review, require warning signs spaced approximately every 10 meters or less. The municipal requires “warning signs” from a liability perspective, but it has been shown that these signs, by them selves, are as effective as the fence itself in keeping out trespassers even when, or if the fence is turned off. When you have a “lethal looking” fence combined with “warning signs”, the fence now becomes almost totally effective is stopping passage through or over the fence. (NOTE: there is absolutely NO device or method devised that has proven to be 100% effective)

 The “warning signs” take a lightly designed fence and transform it into a “most lethal looking” fence. Keep in mind that the electric fence is completely non-lethal and not dangerous to the smallest most vulnerable animal. When shocked repeatedly, new born baby rabbits are not harmed. The fence will administer a stinging and most unpleasant feeling shock, but will not physically harm an animal, child, or adult. So you need to understand, that the fence is an elaborate bluff, that will slap their wrist hard if someone chooses to ignore it.

 Because of the “non-lethal” action of the electric fence, the legal liability exposure is very small, however, warning signs about every 10 meters or so, in plain sight, as close to eye level as possible, minimize the legal liability exposure to almost nothing.

 If you were to plug your fence into the wall outlet/receptacle then you might indeed kill somebody. Your liability exposure is extreme. Your insurance will NOT cover you. Wall voltage is not only dangerous, but mostly not effective. At 220 volts, dry cement, and rubber slippers will insulate you from a shock, however, if someone accidentally comes in contact with an electrical ground you may easily be killed.

 Dry ground combined with insulated footwear is why 10,000 volts is used, so as to carry the shock through the ground and the footwear. The “pulse” technology is what makes it both painful and non-lethal. This technology has been tested and proven for over 75 years of usage around the world. There are safety standards all over the world that when met, insure that the shock is “non-lethal”. The pulse length is approximately 100 microseconds (0.0001 seconds) If you use house voltage on the fence, the fence now becomes potentially extremely LETHAL !

 If you were to hold your arm over a burning candle for several seconds, you would receive a nasty burn. If you were to pass your arm through the flame of an acetylene torch (which is much hotter than a candle) and do it quickly enough, you would escape and not even singe a hair. That is primarily the safety principle with pulsed electricity charging electric fences. The safety standards mandate the maximum voltage (not to exceed 10,000 volts) and the maximum pulse length (not to exceed 300 microseconds) of the pulse and the repetition rate (not less than ½ second) of the pulse. We use a fence charger that peaks out at about 9,500 volts and has a pulse length of approximately 100 microseconds and repeats approximately once per second which are all well within the safety standards that have been set and tested accordingly. 

INSTALLING THE FENCE WIRES:

    
                                            click on picture for more detail

All wires including the ground return wires and the high voltage wires are to be installed and mounted on insulators. This is necessary to complete the psychological component and so the trespasser cannot   distinguished the ground wires from the high voltage wires.

The maximum spacing between the wires should be approximately 6 inches or about 15 centimeters. This has been tested and shown to be the most effective spacing to deter people from trying to go over or through the fence.

The fence should be designed and installed with an odd number of wires, with both the top-most wire and the bottom-most wire being high voltage wires.

However, when there is an excessive amount of foliage around the fence, the top wire might be a ground wire. This is to reduce the number of faults when the high voltage wire is partially shorted with fronds or banana leaves.

SPECIFIC DESIGN SOLUTIONS

Typical wiring hookup and installation

(goto MAIN MENU)

This describes a 4 wire/strand extension above a standard concrete wall. The bottom strand is stretched about 3 inches (7.5 cm) above the cement wall. The other strands have approximate 6 inches (15 cm) spacing from each other. In this design, the top strand is a grounded to provide a measure of "false alarm" protection from falling foliage. 

All strands are insulated so the grounded wires cannot be distinguished from the high voltage wires.

In this installation, the grounded strands are connected together in a standard common parallel fashion. This common ground includes three (3) 8 foot ground rods driven at least 7 feet into the earth/ground. An absolute minimum of 2 grounds are always recommended to provide a good ground over the length of your fence. Also connected to this common ground are the output ground terminals of the fence charger 220VAC to 12VDC  and the voltage monitor.

The high voltage strand is broken at the charger connection so the high voltage can only travel in one direction. This bottom high voltage strand is then splice/connected to the next upper high voltage wire at the far end end of the fence installation, and the voltage is looped and travels back to the far left which is the other end of the fence installation, and then connected to the lower high voltage strand and back to the start for a connection with the high voltage monitor. 

This type of loop connection of the high voltage strands insure that if the high voltage is cut or shorted or lost in any manner, the high voltage monitor will provide an alarm. 

So the voltage leaves the fence charger; travels around the fence; connects to the next strand and travels all the way back to the far end of the installation; and then back to the beginning. It DOESN'T, however, connect back to the charger, but instead, connects to the voltage monitor, as shown. This makes the high voltage a single loop originating from the charger and traveling around and back to the voltage monitor. 

The monitor senses the voltage and if the voltage is cut or shorted, then the "fail safe" relay (which closes if the battery fails also) in the monitor makes contact and sounds whatever alarm is connected to it. It is a good idea to power the alarm siren to a separate battery or 12VDC power source.

This is the most common installation, and this and variations of this design account for probably 80% of all installations. 

(goto MAIN MENU)