What is a fence energizer?

It’s a device that takes in electrical energy from an outside source (either a 110V outlet or a battery) and then pushes the energy out through the positive fence terminal in very brief, high-voltage, high-amperage pulses. The negative ground terminal absorbs any excess pulse energy back into the energizer.

Two basic energizer types:

Most modern fence energizers send very brief (less than 3/10,000 of a second in duration), high-voltage pulses (usually 2,000–6,000 volts) of electrons down the conductor every 1–2 seconds. Though powerful enough to deter animals and poultry, pulses this brief and this infrequent almost never pose a fire risk when the conductor is near combustible material. There simply isn’t enough “on” time for heat to build and allow ignition to occur.

Dry, sandy or rocky soil increases resistance—a weaker, less effective pulse occurs that does not deter animals. To overcome this, use additional ground rods, Positive/Negative fence and/or a higher output energizer.

Should you energize the fence?

• A common mistake is not electrifying it. Electric fence is a pain barrier, not a physical barrier. Animals conclude the fence itself is painful—and then avoid it.
• Energized fences last longer and require less maintenance—because animals do not crowd, rub or scratch on them.

Issues to consider before buying an energizer

• Amount of wet/green weed contact with the energized wires. A 1/4 mile permanent fence 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 (3-6" off the ground) cause much more leakage from weed contact than higher wires (> 18").
• Species to be contained or deterred: Animal and birds vary in their internal resistance (in ohms) to electricity. In order from most to least affected by an energized pulse are: pigs, horses, cattle, canines (wet noses, bare pads), raccoons, sheep, goats, deer, geese, chickens and rabbits. Heavy animals tend to be the most affected because their weight compresses the topsoil which reduces its electrical resistance.
• 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 soil via weeds or poor quality insulators.
• Power source: Plug-in (AC) energizers are best if the fence is close to a 110V power outlet. Solar energizers may be a good option for fences far away from an outlet.
• Farmstore “Miles of Fence” rating: This can be misleading because in many cases the rating refers to a single strand fence with the energized wire very far off the ground and with no weed or grass contact. Instead, Premier indicates how many rolls (or feet) of weed-laden fence can be energized.
• Cost: The most expensive energizer is the one that isn’t big enough and therefore results in escaped animals or predator attacks.

We collect ratings and reviews from our customers about all of our products—including energizers. If you’re still not sure which energizer is the right one for your situation, please call us at 800-282-6631. Our folks are used to helping in a soft, no-pressure way and have used many of the units we sell on their own farms.

Other firms may supply more units—but no one supplies more energizers directly to end-users and tracks the results. When you join our community of satisfied customers, you tap into that experience and expertise.

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.

To Reduce Risk and Liability...

Are electric fences a serious safety risk to humans?

Because touching an electric fence is painful and the voltages are high, most assume that the risks from an energized fence must also be high. That’s a myth. Consider that millions of people throughout the world are "exposed" to millions of electric fences every day—yet they are involved in (but are not always the cause of) less than one human death or serious injury per year worldwide. Compare that to the number of annual injuries and deaths that occur from human exposure to tractors, skid loaders, ladders, PTO shafts, balers, mowers, combines, bulls, stallions, rifles, shotguns, knives, etc. This is not to suggest that there is no risk at all. There is, indeed, a small level of risk. And with risk, there is also liability to the fence’s owner.

What NOT to do!

• Never place your head or upper spine near an electrified wire. Accidental head or neck contact can occur when pushing a voltage probe into the soil. Be careful when doing so to avoid head-to-wire contact!
• Never attempt to step over or climb through an energized fence of any kind.
• Never encourage anyone to touch an electric fence.