Electric Fence FAQs
Before you buy or build an electric fence…some common key fence questions—
Will the fence be moved? If so, how often?
- Daily or weekly (temporary/portable)—
Temporary or portable fences are quick to install and remove. To eliminate the need for large end and corner posts, the fence strands (whether single, multiple or a mesh/netting) must be only hand-tensioned. And they must be electrified properly.
- Moved each season or less (semi-permanent)—
Can be an interim barrier until a more permanent fence is installed. This allows folks to field-test fence and gate locations to see what works best. Usually consists of electrified net or multiple electrified strands under low tension—supported by stronger/thicker posts than temporary fences. Will need more maintenance attention than permanent fences.
- Never moved (permanent)—
For boundary and subdivision fences for land that’s owned by the user—and whose usage is not likely to change! Requires strong wood, steel or fiberglass posts that support high-tensile wires, woven wire, rope or wide tape—of which one or more strands are electrified. More reliable than other options but more expensive to install. May require a professional installer.
What’s the fence’s location?
The best design hinges on the following:
- Is the terrain flat?
- Will the fence go over hills, across ditches, or around curves?
- Is fence line brushy or with trees?
- Are the soils rocky, very soft, sandy or firm?
Do the animals know the fence?
Local animals and wildlife get to know a fence by appearance, location and pain memory. If it’s a strong or painful fence, they avoid it. On the other hand, new animals just off a truck often charge into permanent fences and straight through temporary or semi-permanent fences. That’s why strong, tall, visible permanent fences are essential for corrals and feedlots. Temporary fences that are not physically strong pose the greatest risk of escape to newly acquired animals. It pays to train them to it inside of a permanent fence.
What specific animals need to be fenced in or out?
Always design and build for the most difficult species. Rules of thumb:
- Most sheep and goat fences will stop cattle. The inverse is not always true.
- Fencing adult males (bulls, rams, stallions, billies) in/out during breeding season requires taller fences with closer wire/strand spacing and more powerful electric pulses (in joules, not volts).
- Fences for mixed sizes (ewes with lambs, cows with calves, etc.) need more strands than uniform animal groups.
- Certain breeds need better fences (e.g. flighty Romanov sheep, tall Columbia sheep and tall Chianina cattle).
Should you energize the fence?
- An electrified strand has a zone of pain. Fewer strands are needed if one is energized. Both material and the labor to install is reduced.
- Energized fences last longer and require less maintenance—because animals do not crowd, rub or scratch on them. So the fence wires (including wires that are not energized) require less tension to do their job. And braces and corner posts will last longer.
- Animals are more surely contained or excluded during breeding and weaning.
How visible should the fence be?
It depends upon the species. Horses, deer and antelope move at high speed and have restricted color perception (compared to humans). They often fail to see small or dark fence wires like HT wire, MaxiShock and some polywires and charge through them. That’s why it’s wise to include one or more strands of bicolored rope or tape (both highly visible) in fences.
How keen will animals be to breach the fence line?
Build for the worst-case situation (if you can afford to do so). Some situations that require more secure fences:
- Hunger. Starved animals will eventually challenge most fences.
- Weaning. Strong physical barriers are essential to success.
- Breeding. Libido induces all creatures to challenge rules and fences.
- Boredom. Animals in corrals, stalls and feedlots often crave any entertainment or activity.
- Gateways and handling yards. Animals often push each other into fences when being moved.
- Goats. Without a doubt, they are escape artists.
- Frightened animals. Predators or loud noises can cause prey species (e.g. horses, goats, turkeys) to run in terror straight into, under, over or through any fence, no matter what fence design (netting, hi-tensile or woven wire).
Are long, dry periods common?
Electric fences typically rely on soil moisture as a conductor. When the soil is dry or covered in dry snow, normal electric fences and low-impedance energizers may not work effectively to keep animals in/out. Solutions for this are:
- Use a wide-impedance energizer. They’re less affected by dry soil.
- Integrate ground-return wires (connected to energizer’s negative terminal) into the fence. Animals must touch 2 strands (a negative and a positive) but it works well.
What’s the cost if the fence fails?
The higher the potential cost (in time and money) of a failure, the more reliable the fence design should be. Examples:
- Along public highways. In some states the landowner is liable for damages to vehicles and humans.
- Around stored feed. If animals gorge on grain, death may occur.
- High-value protection, e.g. gardens, evergreens; or livestock from predators.
- Fences with animals on both sides. Mix-ups are time-consuming and costly. Neighborhood relations can be strained. Unpleasant lawsuits (aren’t they all?) may occur.
Why are lane and corral fences considered special situations?
Animals are often forced into contact with these fences. Therefore, they need better visibility, more strength and, if possible, no energized wires.
Will heavy snow or ice occur?
Ice can bring down the strongest power lines so all fences are vulnerable to it. Some cope better than others.The question is—are your animals likely to challenge the fence before the ice melts?
What is a fence energizer?
A box that takes in electrical energy from an outside source (either a battery or a 110 volt outlet). The energizer pushes the energy out through the positive terminal in very brief, high voltage, high amperage pulses. The ground (negative) terminal’s purpose is to absorb any excess pulse energy back into the energizer.
How high is the voltage of a pulse?
Up to 14,000 volts. That sounds extreme—but static electricity is often as much as 25,000 volts.
How brief is the pulse?
Less than 3/10,000 of a second. It’s important that it be brief to enable animals and humans time to move away (among other reasons).
Will I feel anything if I touch both the terminals while the energizer is on?
Yes and no. You will feel nothing if you touch only one. But if you accidentally touch both at the same time (we strongly advise against this!) you will feel the full impact of the pulse. Note: We never contact the terminals (even when the energizer is off) without first carefully touching both terminals with an insulated metal wire!
So what is an electric fence?
An extension of the 2 terminals of the fence’s energizer. The negative (earth) terminal is extended by driving metal rods into the soil and connecting them to the negative terminal with conductive wire. Because soil moisture is a good conductor this method makes the soil for miles around (not an exaggeration) an extension of the earth/ground terminal. So, in effect, animals, humans and grass are “standing” upon an extension of the energizer’s earth terminal. The fence terminal is extended by attaching conductive wires or electroplastic cables to it. They are suspended above the soil and kept separate from it by devices called insulators or non-conductive posts.
What happens when grass touches the energized wires in a fence?
The fence wire is “pressurized” with excess electrons from the pulse. Green vegetation is a conductor—particularly when wet. When it contacts an energized wire, the pressurized energy (measured in volts) is pushed down through the moisture in the stem to the soil. Folks call this a “leak” (similar to a hole in a water hose) or a “short.”
What happens when an animal touches energized wires?
The high voltage of the pulse pushes electrons through the animal’s point of contact (often the nose or ears), then through the body’s tissue and fluids and out through the feet/hooves/paws into the soil moisture.
Issues to consider before buying any energizer:
- Total length of fence: This is actually of minimal importance. Why? Because even small units will energize long fences and stop animals—if there are no leaks of energy to the ground via weeds or poor insulators.
- Amount of wet/green weed contact with the energized wires. Very important. 1/4 mile of hi-tensile wire that’s covered with weeds and is only 6 in. above wet soil may leak/drain away more energy than a 3 joule energizer can provide!
- How high off the ground will the lowest live wires be? Low wires mean much more electron leakage from weed contact than higher wires. More leakage means you need an energizer with high joule outputs at 200Ω.
- Species to be contained or deterred: Animal and birds vary in their internal resistance (in ohms) to electricity. Wide-impedance units (or large low-impedance ones) are best for species with high internal resistance (poultry, goats, deer). Low-impedance units work well for cattle, horses and pigs.
- Climate: Low-impedance units are ideal for places where the grass stays green. Wide-impedance units are superior when grass turns brown for 2 or more weeks.
- Soil: Wide-impedance units are better for rocky and/or sandy soil. Low-impedance units are better for clay and/or loam soils.
- Power source: 110v AC plug-in units are best if the fence is close to power. If not, look at solar (battery) options.
- Cost: The most expensive energizer is the one that isn’t big enough and therefore results in escaped animals or predator attacks.
I’m confused by all the energizers Premier offers.
All that we offer are proven reliable units. But some folks have strong brand preferences based on prior experience or advice from others. By offering more we enable them to access our other products and our support services. But we understand the problem this causes folks new to electric fences. If you have questions, call us at 1-800-282-6631. Our folks are used to helping in a soft, no-pressure way. And we’re okay if you then put down the phone and order online to save on shipping cost.
The two basic energizer types compared...
Plug-In units:Energy input is 110v AC (plug-in).
- Least cost to purchase and operate per joule of output.
- Cold temperatures don’t affect them.
- Because they are available with higher outputs, they are essential for complex whole farm systems—with long permanent fences plus portable electric fences.
- Best for fences that experience high weed contact on live wires.
- Can be complex to install. High output needs more ground rods. Needs lead out wires (which often must be buried), “feeder” fences and switches, underground cable across gateways, etc.
Battery and Solar units:Energy input is 12v DC (battery). If solar, the battery is recharged by a panel that is directly attached to the energizer’s case.
- Because they need a battery, these units are more costly to purchase and operate than plug-in units (but still less so than solar units).
- Solar units always cost more per joule than AC units because they include a battery, a solar panel and a larger case.
- Batteries are less effective in colder temperatures.
- Solar units are very portable—reduced need for lead-out wires.
- Most farm store solar units are too weak, in joules of output, to stop more than a horse or dairy cow.
- Limitations on output (due to price, size and weight) also limit the amount of weed-laden fence that can be properly energized.
Why Premier’s “know-how” is unique…
Other firms may supply more units—but no one supplies more units direct to end-users and tracks the results. We know what failed, when and why for 40,000 energizers. If you join our list of satisfied customers, you tap into that wealth of expertise. It doesn’t make us perfect…just better.
Why is the color of grass (green vs brown) a factor in choosing a suitable energizer?
Green grass means the soil is moist, so the soil will have less resistance to a pulse. Also, the high-moisture green stems and leaves are able to drain away far more energy from an energized fence thus reducing the pulse energy available to an animal. All of this suits the capabilities of low-impedance energizers. Brown grass suggests the opposite.
Which animals are most affected by low-impedance electric fence pulses?
In order from most to least: pigs, horses, cattle, canines (wet noses, bare pads), raccoons, sheep, goats, deer, geese, chickens and rabbits. This order assumes adult animals contacting the fence with their nose/beaks.
Shortcuts to finding the right energizer unit for you...
- Least-cost small to midsize plug-in units: HotShock 5, IntelliShock 10, 20, 31. Patriot P5, P10, P20, P31.
- Least hassle to set up: All PRS solar units and Speedrite AN90.
- Most hassle and risk of failure: DC units that require recharging the battery with a recharger.
- For wildlife fences: Most plug-in units that are AC/DC. Their pulse frequency is up to 25% faster than most other energizers.
- DC units for cattle, horses and deer fences (these fences need high output but won’t have wires close to the soil): IntelliShock 10, 20, 31 units. Their energy usage is uniquely low in these situations.
- When soil is dry and grass is brown: Long fences: Kube 4000, IntelliShock 31, 506. Short fences: Kube 4000
- High green-weed contact: Long fences: High joule units—HotShock 1000; Speedrite 6000/12000. Short fences: HotShock 600, Kube 4000; IntelliShock 20, 30; Patriot P10, P20, P30 and PRS 100 units.
NOTE: Do not use an energizer that is labeled high impedance, continuous current, weed burner or weed chopper. We recommend only low or wide impedance energizers. Continuous current (high impedance) energizers have a pulse type that is long (in time) but low in energy. Low impedance have pulses that are very short (in time) but higher in energy. The long duration continuous current pulses create a spark that is also long in duration - long enough for it to set fire to grass/weeds/leaves/needles that might touch the fence. In our opinion they should never be used on any fence - for this reason. They must not be used on electroplastic fences (can melt the plastic). Low impedance pulses are so short (3/10,000 of a second maximum) in time that heat build up is less likely.
Warning: In 1991 an accidental fatality occurred when a young child’s head contacted an electrified fence while the child was crawling on wet grass. The fence was correctly installed and functioning properly. The energizer was a UL approved unit. As a result, Premier strongly advises against allowing toddlers access to any electrified fences. Also, due to this incident and others, experts now suggest that human contact by an energized wire to the head and neck may be the most dangerous point of contact. We urge all to especially avoid this kind of contact.