We receive many electric fences questions, such as “how do they work” and “what parts do I need for my fence.” We’ve listed a few of the most frequently asked questions to help you answer your questions.
Check our our list of frequently asked questions below. If you have more questions about the usage of electric fence equipment and/or components, please feel free to contact us.
Questions:
- How does an electric fence work?
- How does a ground work?
- How important is the grounding system?
- How many grounding rods do I need to make my fence work? How do I install them?
- How do I select the correct sized energizer?
- What are volts, amps and joules?
- What does low impedance mean?
1. How does an electric fence work?
An electric fence is simply a large open circuit waiting to be closed. The electric fence energizer or charger sends a high voltage pulse of electric energy through the wire, tape or rope at short intervals, usually between one and two seconds. The circuit is closed when an animal, which is standing on the ground, touches the fence. The electric energy in the fence wire flows from the fence, through the animal’s body and to the ground causing the animal to be shocked. The animal will only respect the shock if both the voltage and energy are at proper levels. Environmental, fence and ground conditions influence the level of shock received. It takes a minimum of 700 volts to effectively control short haired breeds of cattle, pigs and horses while it takes about 2,000 volts for long haired cattle, sheep and goats. Depending on the type and breed of animal, it may take multiple shocks from an electric cattle fence before they are fully trained to have respect for the electric fence.
2. How does a ground work?
Upon leaving the electric fence energizer, the electric current travels along the wires and connections of the solar electric fence. It is seeking all possible routes back to Earth. These routes include animals, people grass etc. When an animal comes in contact with the wire on a livestock electric fence, the energy passes through its body and returns to the ground causing an electric shock.
3. How important is the grounding system?
The grounding system is a vital part of the system enabling the correct return of electrical pulses (from the electric fence energizer) through the animal from the contact point on the fence to the ground. Without a sufficient ground, the electric fence will be limited in effectiveness of providing a “shock”.
4. How many grounding rods do I need to make my fence work? How do I install them?
Grounding rods should be at least 6 feet long. Even though one grounding rod may work, it is recommended for best results to use 3 rods spaced 10-12 feet apart. The first rod should be within 25-50 feet from the energizer and driven down deep into the earth. The larger your fence, the more grounding rods you should have since more grounding rods increase the shock potential. Connect the rods together and then connect them to the energizer ground terminal using highly conductive wire (the wire should be a minimum of 12.5 ga in diameter). Water the ground after installation and during dry spells if necessary.
5. How do I select the correct sized energizer?
The energizer must deliver sufficient shock in proportion to the requirements placed on it. The power output should be selected based on the following calculations. Location of electric fence energizer (access to A/C power), type of animals, length of the above-ground or underground electric fence, number for strands of wire, conductivity of wire, vegetation present on the fence and soil conditions for grounding.
6. What are volts, amps and joules?
Volts or voltage is the driving force behind the flow of electricity in a wire. It is often related to the pressure water has in a pipe. The more pressure pushing water through a pipe is analogous to the voltage pushing energy through a conductor.
Amps or amperage is the measurement of electrical current through a wire. It is the current or amps that determine the strength of the shock felt from a permanent or temporary electric fence. The higher the amps of current, the higher the strength of the shock. Continuing the water pipe analogy, amps is roughly like the flowrate of water coming out of the end of the pipe.
A joule (pronounced jewel) is a unit of work or energy. It is the energy expended in one second by a current of one amp at a potential of one volt. One joule is equal to one watt of power in one second.
7. What does low impedance mean?
Energizers that are low impedance energizers have the ability to regulate their output and maintain a constant voltage supply to the fence even as the grounding and fence conditions deteriorate as well as increased vegetation contact. This means as more vegetation draws amperage from the electric fence (short circuiting or grounding the fence), a low impedance energizer will produce more energy or joules to overcome this loss due to plants while maintaining adequate levels for animal control.
