Electric fence - Wikipedia. Electric fence of high tensile wire. Not all strands are electrified, only those attached to the fence posts with black insulators. An electric fence is a barrier that uses electric shocks to deter animals from crossing a boundary. The voltage of the shock may have effects ranging from discomfort to death. Most electric fences are used today for agricultural fencing and other forms of animal control, although they are frequently used to enhance the security of sensitive areas, such as military installations, prisons, and other security sensitive places; places exist where lethal voltages are used. Design and function. This material is more visible than wire, but most often used for temporary fencing. Electric fences are designed to create an electrical circuit when touched by a person or animal. A component called a power 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 a ground or earth rod. A person or animal 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 effects of the shock depend upon the voltage, the energy of the pulse, the degree of contact between the recipient and the fence and ground and the route of the current through the body; it can range from barely noticeable to uncomfortable, painful or even lethal. Fence energizers. The pulses were wide and the voltage unpredictable, with no- load peaks in excess of 1. The switch mechanism was prone to failure. Later systems replaced the switch with a solid- state circuit, with an improvement in longevity but no change in pulse width or voltage control. These were responsible for many grass fires when used during dry weather. An electric fence is a barrier that uses electric shocks to deter animals from crossing a boundary. The voltage of the shock may have effects ranging from discomfort. Find top-rated Los Angeles schools, read recent parent reviews, and browse private and public schools by grade level in Los Angeles, California (CA). The New Jersey Judiciary is committed to ensuring equal access to our courts and fairness in our procedures. Click here to learn more about the Supreme Court Advisory. Provides surgery residency, laparoscopic nephrectomy, kidney and pancreas transplant, cardiac disease, neurology, neurosurgery, obstetrics and childbirth health care. The latest news, sports and life in general throughout western Wayne and Oakland counties, from the Observer and Eccentric. WBRZ News 2 is an ABC affiliate and Baton Rouge's only locally owned and operated television news source for more than 50 years. WBRZ provides coverage of local news. National organization representing county governments in the United States. Livingston BagelAlthough still available, they have declined in popularity. Most modern fences emit pulses of high voltage at a given interval of time, and don't take into account whether there is an animal or person touching the conductive wires, except for the voltage multiplier based electric fence charger that stores high voltage potential and dumps its charges as soon as a conductive load (grounded animal/person) touches the wires. Depending on the area to be fenced and remoteness of its location, fence energizers may be hooked into a permanent electrical circuit, they may be run by lead- acid or dry cell batteries, or a smaller battery kept charged by a solar panel. The power consumption of a fence in good condition is low, and so a lead- acid battery powering several hundred metres of fence may last for several weeks on a single charge. For shorter periods dry cell batteries may be used. Some energizers can be powered by more than one source. Fencing materials. Less often, woven wire or barbed wire fences can be electrified, though such practices create a more hazardous fence, particularly if a person or animal becomes caught by the fencing material (electrified barbed wire is unlawful in some areas). White picket fence surrounds a front-yard lotus pond in a Hubei village. Temple is a top-ranked research university. A leader in education, science, healthcare and the arts, we are the powerhouse that charges the Philadelphia region. Synthetic webbing and rope- like fencing materials woven with fine conducting wires (usually of stainless steel) have become available over the last 1. The electrified fence itself must be kept insulated from the earth and from any materials that will conduct electricity and ignite or short out the fence. Fencing must therefore avoid vegetation, and cannot be attached directly to wood or metal posts. Typically, wooden or metal posts are driven into the ground and plastic or porcelain insulators are attached to them, or plastic posts are used. The conducting material is then attached to the posts. Electrified palisade fences are usually made from painted mild steel, galvanized steel, stainless steel or aluminium. Typically the fences are 2. The palisade fence is mechanically stronger than a typical steel cable electric fence to withstand impact from wildlife, small falling trees and wildfires. Livingston Public SchoolsThe top spikes are electrified while the bottom slats of the palisade are grounded. History. Published in 1. Mark Twain's novel A Connecticut Yankee in King Arthur's Court, uses an electric fence for defensive purposes. David H. Wilson obtained United States Patent 3. He constructed an experimental 3. Texas in 1. 88. 8, but it was not successful. In 1. 91. 5, during World War I, the German army installed the . The fences covered 3. An estimated 3,0. Electric fences were used to control livestock in the United States in the early 1. United States and New Zealand. An early application of the electric fence for livestock control was developed in 1. At RWJBarnabas Health, the comprehensive care you need is in reach! Call today for cardiac, cancer, pediatrics, and women's healthcare. Built from a car ignition trembler coil set, Gallagher used the device to keep his horse from scratching itself against his car. Gallagher later started the Gallagher Group to improve and market the design. A variety of plastic insulators are now used on farms throughout the world today. By 1. 93. 9, public safety concerns in the United States prompted Underwriters' Laboratories to publish a bulletin on electric shock from electric fences, leading to the ANSI/UL standard No. Cox, a farmer in Adams County, Iowa, invented an improved electric fence bracket and was issued United States Patent No. June 2. 3, 1. 97. This bracket improved electric fences by keeping the wire high enough above the ground and far enough away from the fence to permit grass and weeds growing beneath the wire to be mowed. The brackets attached to the posts by what may be called a . Improvements include: Polyethyleneinsulators replacing porcelain insulators, beginning in the 1. Polyethylene is much cheaper than porcelain and is less breakable. Improvements in electrical design of the fence energizer, often called a . In some jurisdictions, certain types of electrical outputs for fences were unlawful until the 1. In other areas, signage requirements and other restrictions limited usability. Many US cities continue to have outdated laws prohibiting electric fences to prevent agricultural fences from entering the city. Houston in Texas for example, changed their ordinance that prohibited electric fencing in 2. The risk of injury to livestock (particularly horses) is lower compared to fences made of barbed wire or certain types of woven wire with large openings that can entangle the feet. Its disadvantages include the potential for the entire fence to be disabled due to a break in the conducting wire, shorting out if the conducting wire contacts any non- electrified component that may make up the rest of the fence, power failure, or forced disconnection due to the risk of fires starting by dry vegetation touching an electrified wire. Other disadvantages can be lack of visibility and the potential to shock an unsuspecting human passer- by who might accidentally touch or brush the fence. Many fences are made entirely of standard smooth or high- tensile wire, although high quality synthetic fencing materials are also beginning to be used as part of permanent fences, particularly when visibility of the fence is a concern. Conventional agricultural fencing of any type may be strengthened by the addition of a single electric line mounted on insulators attached to the top or front of the fence. A similar wire mounted close to the ground may be used to prevent pigs from excavating beneath other fencing. Substandard conventional fencing can also be made temporarily usable until proper repairs are made by the addition of a single electric line set on a . It is also popular in some places for confining horses and pack animals overnight when trail riding, hunting, or at competitions such as endurance riding and competitive trail riding. Typically, one or more strands of wire, synthetic tape or cord are mounted on metal or plastic posts with stakes at the bottom, designed to be driven into the ground with the foot. For a hand- tightened temporary fence of electrified rope or web in a small area, these are usually spaced at no more than 1. Larger areas where tools are used to stretch wire may be able to set step- in posts at larger distances without risk that the fencing material will sag. With temporary electric fencing, a large area can be fenced off in a short period. Temporary fencing that is intended to be left in place for several weeks or months may be given additional support by the use of steel T posts (which are quickly driven in with hand tools and unearthed with relative ease, using a leverage device), to help keep the fence upright, particularly at corners. Livestock owners using rotational grazing in set patterns that are similar from one year to the next, may permanently drive a few permanent wooden fence posts in strategic locations. Portable fence energizers are made for temporary fencing, powered solely by batteries, or by a battery kept charged by a small solar panel. Rapid laying- out and removal of multiple- strand temporary electric fencing over a large area may be done using a set of reels mounted on a tractor or all- terrain vehicle. For sheep, poultry, and other smaller animals, plastic electric netting may be mounted on insulating stakes . However, some animals learn to avoid the shock, either by running under the fence quickly between pulses, or by pushing other individuals through the fence. Animals with thick woolly coats (such as sheep or highland cattle) may learn to push through the fence themselves, using their coats as electrical insulation. Some animals also learn to recognize the slight clicking sound made by some electric fences and thus can sense when the fence is off. Wild animals. Examples include deterring deer from entering private property, keeping animals off airport runways, keeping wild boar from raiding crops, and preventing geese from soiling areas used by people. Electric fencing has been extensively used in environmental situations reducing the conflict between elephants or other animals and humans in Africa and Asia.
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