Ann Larkin Hansen - Electric Fencing: How to Choose, Build, and Maintain the Best Fence for Your Plants and Animals. A Storey Basics Title

Electric net fencing is the portable fence of choice for sheep, goats, and poultry on smaller acreages.

Whether permanent or temporary, electric fencing has advantages and disadvantages compared to nonelectric, traditional fencing (see ). The most obvious difference between the two is that traditional nonelectric fencing whether made of wood or wire provides a physical barrier, while electric fencing presents a psychological one. Electric fences are physically weak; the fear of electric shock is all that stops the animals.

For most farmers the advantages of an electric fence far outweigh the disadvantages. This book will cover the basics of planning, installing, and maintaining an electric fence system appropriate to what you are containing or protecting.

Practicality. Electric fencing is cheaper than nonelectric, more versatile, and more effective in many situations.

Portability. Lightweight posts and plasticized wires make it quick and simple to put up and take down a temporary fence almost anywhere.

Need for frequent inspection. When not if it gets shorted out by lightning, a broken wire, or some other mishap, the electric fences effectiveness is gone and you may have animals where you dont want them.

Invisibility. You cant tell just by looking whether your fence is connected correctly to the energizer or if there is enough voltage on the wires. You can overcome this drawback by the regular use of a fence tester.

When an animal touches a charged fence, the electricity passes through its body to the ground and back to the energizers grounding system. This completes the electrical circuit and gives the animal a memorable shock. The shock is what makes the fence work: animals conclude that the pain isnt worth the reward of pushing through the fence. This is how they are trained.

The intermittent static electrical charges on an electric fence are generated by a fence energizer (also called a fencer, power unit, controller, or charger), a box of electronic components that convert standard low-voltage current from an electrical outlet or storage battery to the high-voltage pulses along the fence wire.

The most important principle of electric fencing is that electricity doesnt shock unless it is moving. For electricity to move there must be a complete circuit; that is, the charge generated by the energizer must be able to find its way back to the energizer.

Clearly, then, the energizer is only part of the circuit; contrary to popular belief, it alone does not control the effectiveness of an electric fence. The type and condition of the wires and whether there is enough moisture in the ground to conduct electricity both play critical roles in how effective a fence will be.

Two additional factors help to make a fence effective:

• Properly insulating the charged wires from the ground so the current flows only through the animal
• Having a good ground system, so that when the current is flowing it doesnt get diluted on its way back to the energizer

The animal is the switch that completes the current in an electric fence system.

Electric-tionary

To understand any discussion of electric fencing its helpful to know some basic electrical concepts. The simplest way to grasp these is to compare the current along a wire to water in a hose.

Volts are the equivalent of water pressure. The more pressure (volts), the farther the charge can jump. Voltage must be higher if the charge has to jump farther to penetrate thick fur or hair.

Amps are the equivalent of water volume. The longer your fence or the more faults present, the more amps youll need to fill the line.

Watts are volts x amps, and are used to describe how much electricity is being drawn from the power source. Watts also underlie the next, very important concept.

Joules are watts multiplied by time. One watt for one second = one joule. The size of a fence energizer is commonly ranked by the number of joules it generates. Joules are related to the amount of fence the energizer is capable of charging effectively, but the relationship is not straightforward, as we will discuss in chapter 2.