Volts vs Joules

When determining the electrical needs of your fence system it is important to recognize the difference between volts and joules. A volt is a unit of measure assigned to the electrical potential or voltage across a conductor. However a joule is a unit of energy or work done, to move an electric charge through an electric potential. The following are mathematical understandings of volts and joules, which later will be put into layman’s terms according to choosing the correct energizer.

The difference between volts and joules can be simplified by remembering that joules are the energy used to create voltage on the fence line. Whereas, voltage is the speed at which the current is moving along the line. The diagram below is an excellent example of volts and joules.

    Joule = Truck

    Hill = Fence

    Speed = Voltage

    Weight = Ohms/Weed load/Resistance

When selecting a truck to haul livestock, you must first determine the heaviest load that the truck will need to pull. The truck must be capable of pulling the trailer and stock successfully. Choosing the appropriate energizer for your fence system is a very similar concept. Consider that the voltage is carried by the speed at which the charge travels through the fence line and joules will be created by the energizer according to the watts per second of output. In an electric fence system, a high voltage is important for making sure that an electrical charge can find its way through the hair on the animals it is intended to contain or exclude. The more or thicker the hair, the greater the voltage required. The higher the voltage, the greater the charged wire’s ability is to shock the animal that happens to touch the wire. The longer the fence line (mileage) and the heavier the weed load or resistance on the fence, the more output joules the energizer will need to maintain a volt range between 5,000 and 10,000 volts for good stock control.

“It is always best to take the path of least resistance.” This is exactly what to keep in mind when building and choosing an energizer for your fence system. Resistance will decrease voltage on your fence line, because each energizer only has a specified amount of output joules (energy) to maintain the voltage along the conductor (fence line). When resistance begins to diminish output joules the voltage falls low enough that it becomes ineffective because it cannot bridge or arc across the insulation of the hair and hide of the animal. The following are common causes of resistance:

  • Weed Load
  • Induction- Stray voltage bridging to neutral wires, gates, diagonal braces wires, etc.
  • Bad Connections
  • Multiple Splices
  • Broken Insulators
  • Type of wire- Poli-wire, Tape, Ribbon, High Tensile, etc.
  • Rusty Wire


Generally rule of thumb is a minimum of 1 joule of output per mile of fence, to maintain a secure voltage. Kencove is willing to step outside the box and state, “This is not enough power once you do the math!” A mile is equal to 5,280 feet, which in turn is equal to the perimeter of 40 acres. Would you want a 1 joule unit to power your multi-strand 40 acre paddock? The easy answer is “NO”. Kencove would recommend at least a 6 joule unit with an open circuit voltage of 9,500 volts. Understand that if your fence line has numerous sources of voltage leakage, you will need to choose an energizer with a higher joule rating. The truth of the matter is that you can never have too much power. When training livestock having too little power is no different than having no power at all and the fence could actually causes harm to the animal.

Commonly energizer manufactures and dealers overestimate the amount of fence an energizer will securely power. In today’s world it is easy to fall for attractive ads and eye appealing packaging, so when purchasing an energizer look closely at the details.

AnimalRecommended Voltage
Horses2,500 Volts
Cattle3,500 Volts
Cow/Calf Operations4,000 Volts
Sheep/Goats/Heavy Haired Animals4,500 Volts

Many manufactures rate their energizers. A unit which is rated as a fifty-mile unit only means that it can essential power 50 miles of a weed free, well insulated, single strand wire. You will be disappointed if you select an energizer based on miles of fence line. Ultimately, the output joules of the energizer should be the selling point. If only stored joule information is available, you can estimate that output joules are about 70% of the joules stored within the units capacitors.

Remember, that the energizer is the heart of your fence system. It should be accurately sized according to what type of animals are being contained or excluded, the length of the fence line, and how long it could potential be in the future, as well as possible resistance on the fence. This is a basic description of the relationship between volts and joules, and the effectiveness of your electric fence.  Kencove hopes that through your comments and input the readers of this Blog will be able to have greater insight into the proper energizer for their fence.

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  1. Nathanial Shaw
    Posted July 20, 2018 at 3:06 pm | Permalink

    I have two 164’ lengths of electric netting for a couple of goats and and bought a 6.7 joule dc Charger from tsc and have 6kv at the fence but our one goat will almost walk though the fence. So I was looking to getting a charger from you I would looking at the ek13. Would that be enough to keep her from testing the fence

    • Kencove Kencove
      Posted July 26, 2018 at 10:13 am | Permalink

      Nathanial, both energizers are oversized for the amount of fencing you are trying to electrify. I believe the issue stems from having too large of an energizer on your net. You would get a much stronger volt reading on your fence with an appropriately-sized energizer. Our recommended voltage to keep goats in is roughly 7,000 volts. A second issue you are experiencing from your large energizer is the lack of grounding. Can you give our product specialists a call at 1-800-KENCOVE? They will be able to assist you in selecting a properly-sized energizer for your nets.

  2. Cooper Moore
    Posted June 20, 2018 at 10:38 pm | Permalink

    First time to install a hot wire fence. Using a solar low impedance fence charger that puts out 0.15 joule. It’s barely putting out anything. I’ve checked my grounds. Just not getting the output I need. I check the output on the box (hot to ground pegs on the charger) and it’s good. The charge is just not getting to the actual fencing. Suggestions?

    • Kencove Kencove
      Posted July 26, 2018 at 10:06 am | Permalink

      Cooper, if your energizer is testing well, then the issue lies somewhere between the energizer and the fence. What type of wire are you using to connect the energizer to the fence? Also, how long of a fence are you trying to energize?

  3. lee
    Posted October 12, 2017 at 9:30 pm | Permalink

    any way to make cow panels hot

    • Kencove Kencove
      Posted October 17, 2017 at 7:23 am | Permalink

      Lee, we do not recommend energizing cattle panels. You can run an offset wire on the inside or outside of the panel, depending on your situation. Give our sales team a call at 1-800-KENCOVE, and we can help you design a safe and effective fence using cattle panels, offset wires, and an energizer.

  4. Al Tom
    Posted July 30, 2017 at 8:45 pm | Permalink

    I just want something simple to keep critters out of my four raised bed vegetable garden. My raised beds are 4′ x’ 6′ in width and length. I have raised beds because the soil is so hard. I’m not sure if I can drive 6-8 feet of grounding copper rod into the soil. This stuff is totally new to me. Any help with charger size and fencing would be appreciated. Regards, Al

    • Kencove Kencove
      Posted August 1, 2017 at 2:22 pm | Permalink

      Al, we have just the product for you! Have you checked out our electric nets? They are the only American-made electric nets on the market, and they are easy to install, take down, and store, which makes them the perfect protection for gardens! The type of critters you have would determine the best net for the situation. The standard net that we would recommend is our NPCW net. This net is 164’ long and 48” tall with 14 horizontal lines and 3 ½” vertical line spacing. The NPCW can make a 40’ x 40’ square or any shape needed to meet your needs. Multiple nets can be connected if needed to create the perfect protection for your garden. Our nets come with 13 double-spiked step-in posts that are already built into the net, making installation quick and easy.
      I know you mentioned hard soil. Is your soil also dry? If so, you may want to invest in a positive/negative net. We would recommend the NPX. These nets do not require a ground rod. If you do decide on the NPCW, we have a Quick-Ground Rod (item code: MGQ), which is sufficient grounding for a net. The MGQ is easy to install and remove. For your energizer, we recommend the Kencove .50-Joule Solar Energizer (item code: EKS.5H). If you have the option for AC power, we would recommend the Kencove 1-Joule AC Energizer (item code: EK1H). Feel free to give our sales team a call at 1-800-KENCOVE with any additional questions.

  5. Jerry Russell
    Posted February 28, 2017 at 6:42 am | Permalink

    I have a dog enclosure with a fence controller that has a .5 joule output. The fence it protects is only 400′. I keep both adult dogs and small puppies in the enclosure and the single wire prevents digging under the dog fence. I feel like the .5 joule controller is giving too high an output. Would a .2 joule output controller reduce the felt shock? Am I looking at the right thing to reduce the felt shock?

    • Kencove Kencove
      Posted March 1, 2017 at 9:25 am | Permalink

      Hello Jerry, although a .2 joule energizer would be sufficient for your 400′ of fence the voltage will be the same on any size energizer. The “power pushing” the voltage is stronger on larger energizers. You would feel a difference between say a 9 joule vs a 3 joule energizer. However the difference between a .5 joule and a .3 joule would be so small you wouldn’t be able to tell. I wouldn’t be worried about the .5 joule harming your pets. As long as your energizer is low-impedance the pain felt is causing a discomfort rather than harm to your pet.

    • Earl
      Posted April 3, 2017 at 6:32 pm | Permalink

      Thats the purpose of the electric fence. To shock them to stay away from it…..

  6. Sue
    Posted January 2, 2017 at 5:46 pm | Permalink

    Hi, I have 5000 to 7000 volts running through my fence does this mean my earth is working?

    • Kencove Kencove
      Posted January 3, 2017 at 6:22 am | Permalink

      Correct Sue, sounds like you are reading great voltage on your fence line and excellent grounding!

  7. Sue
    Posted January 2, 2017 at 5:45 pm | Permalink

    Hi, I have a 3.2 stored joules energiser. It’s running 3 strands of electric tape around around 1.5 acres. I have a voltage tester and am getting between 5000 and 7000 volts on the fence, depending on where I test it as some of the tape has got damaged where horses have gone through and it’s frayed. If I get this high level of voltage, does that mean my earth is definitly Ok? I’m confused as they are still going through it! Haven’t tested the earth as don’t have any steel cables to put over the tape…. thanks!

    • Kencove Kencove
      Posted January 3, 2017 at 6:24 am | Permalink

      Correct, if you are reading voltage between 5,000 and 7,000 volts your ground bed is working. You may want to replace the frayed pieces of your fence. You are going to start leaking voltage in the frayed areas.

  8. Loreen Pantaleone
    Posted August 24, 2016 at 10:24 am | Permalink

    We rent a property with three strand braided wire. The Zareba 100 mile range unit stopped working (over 5 years old). It’s just for two small paddock areas with total length of rope of 1,500 including bungee gates and installed on T-posts. The 100-mile was overkill and the homeowner agreed, but they boarded several horses and used additional paddocks, which are now hay fields. Do we just need an energizer? Only thing that was attached to the Zareba was a Storm Guard. Would the 3 Joule Energizer be all we need and would you recommend replacing all of the braided that’s existing? There are a few scorched spots where the grounded connectors touched the rope. Thanks for any help.

    • Kencove Kencove
      Posted August 26, 2016 at 7:40 am | Permalink

      First off what are you trying to contain? If you have a fence set up that meets the needs of your animals then yes all you will need is an energizer, and for protection from lightening we recommend using a lightning diverter, you will also need a ground rod kit for the energizer and diverter. If the rope is not in good shape then we have a variety of products. Also keep in mind future additions to your farm, you may want to invest in a larger energizer or different fence depending on what you have now or plan on adding down the road. If you have any additional questions feel free to give us a call at 1-800-KENCOVE our product specialists are great at helping customers figure out the best fence for their needs as well as all the hardware and tools you may not have thought of!

      • Loreen
        Posted December 27, 2016 at 12:28 pm | Permalink

        Sorry for the delayed response. Contains two Thoroughbreds, no other animals.

  9. Kori
    Posted May 19, 2016 at 5:51 pm | Permalink

    I raise boer goats and am having trouble containing them. I run woven wire as primary fence with 2 hot wires 1 on top and 1 on bottom( about 10 to 12 in off ground). I also have about a 70 to 80 yards of 3 strand just electric fence along the driveway.

    1st yr we ran everything off a solor zahbra sp? Solor charger with 1 ground. Seemed to work OK towards end of grazing seasons it lost charge.

    2nd year we split lines into 2 padlocks (removed connecting wire from old fence line to new fence line). I replaced old charger with another zahbra solor charger for old line. The new line I used a 25 mile plug in model with a 4′ t post as my ground. Goats are still getting out.

    New lines has the 3 strand plus 1 bottom where it is woven. Thanks in advance

    • Lacy Weimer Lacy Weimer
      Posted May 23, 2016 at 1:46 pm | Permalink

      I would start by testing the chargers directly at the positive terminal, without the fence attached. Use a fence voltmeter to do the testing. If you are not getting adequate voltages from chargers they may need repaired. If voltage readings are good, check for shorts on the fence line. How deep are the T-posts you are using for ground rods in the ground?

  10. Leslie
    Posted March 5, 2016 at 7:01 pm | Permalink

    We have kinko goats they walk through the electric fence like it’s not there. Should we move up to a 6 joules or higher or to a woven wire fence?

    • Lacy Weimer Lacy Weimer
      Posted March 9, 2016 at 1:07 pm | Permalink

      What is the voltage on your fence line and do you have a good ground bed? Is the ground frozen? If the ground is frozen the Kinko may not be making a good ground. Without a ground there will not be a shock.

      • Leslie
        Posted March 10, 2016 at 4:39 pm | Permalink

        We have installed a 6 joules charger on a 1 bare
        Metal line, 3rd line down (the other lines aren’t
        Connected.to the charger). Its a 100 miles one
        On apx. 1/2 mile of fencing. Good ground wire.
        Still at least 3 are getting out – maby more.Any

        • Lacy Weimer Lacy Weimer
          Posted March 11, 2016 at 9:42 am | Permalink

          Have you tested the voltage on the fence? A fence tester is a must have on the farm. What species are you containing with in the fence? It is important to have at least 18′ of ground rod with the 6 joule unit. I would recommend at least (3) 5′-6′ ground rods spaced 10′ apart. Without a properly working ground bed, the animals may not be receiving the full shock.

          • Lacy Weimer Lacy Weimer
            Posted March 11, 2016 at 9:44 am | Permalink

            Sorry Lesile,
            I forgot you had Kinko goats…if you have great voltage on the fence they may just be cantankerous!

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