How Many Joules on an Electric Fence Do I Need for Cattle?

There are many options for fencing for cattle, and electric fencing is an effective option.

This is especially if you want an easy-to-move and robust fencing option to create sections in a pasture for rotational grazing.

Useful to make a temporary or permanent fence, electric fences only work well if they are set up properly and well maintained.

Cattle need to have a well-maintained fence.

But setting up an electric fence may have a new cattle farmer wondering how many joules of output are required to deliver an adequate shock.

Using 1 joule per mile of fence is recommended to keep cattle contained, as a general rule. This ratio is recommended regardless of whether the number of electrical lines is typically enough for cattle. But, having an appropriate joule rating is only useful if the fence is set up properly.

Keep reading to learn more about setting up an electric fence for cattle, what kind of battery to use, and the power needed.

how many joules do I need for cattle

What Joule Rating Does An Electric Fence Need To Keep Cattle In?

To know why a joule rating is an important aspect of electric fencing, understanding what a joule is will help explain why.

One joule is defined as one watt of power applied for one second.

Joules represent the amount of power a fence charger has to push electricity over a distance.

A joule is comparable to horsepower in an engine giving it the force to carry or push a load.

This is why the amount of joules needs to increase as the distance of the electric fence increases.

If there is not enough force to energize the entire fence, cattle will have no issues finding a weak point to force their way out.

Joules become more important for heavy loads for the amount of resistance the conductive wiring faces.

It can include the length of hot wires and anything which may divert the flow of electricity such as weeds or grounding points.

One important note when setting up an electric fence is it is a psychological barrier rather than a physical one.

The shock the electric fencing wire delivers is more to keep the animal away from the fence rather than pushing through.

Once cattle are trained to an electric fence, they associate it with the shocking sensation and avoid it.

Joules Vs. Volts

Joules and volts differ yet serve two equally important roles in powering an electric fence.

While joules are like the horsepower of a fence, volts are more like the speed the electricity travels.

An appropriate voltage rating along the fence is necessary to give the fence the power to be felt through the hide of cattle.

This provides a painful shock keeping them inside electrified fences.

For cattle, 2,000 volts may be enough during the summer, while a higher voltage of 3,000 volts to compensate for thicker coats may be necessary for winter.

Breeds with particularly long hair like the highland cow may need 5,000-6000 volts.

While many people might think higher is better for both joules and volts, too many joules may result in a higher voltage.

At 7,000 volts, you run the risk of induction, and a 7,000-volt shock is more than necessary for any cattle.

Induction is a phenomenon where an electric wire will transfer another wire or metal in a fence gate without physically touching it. This causes them to be electrified.

While this does not make the electric fence any less effective, it wastes electricity and could cause issues with electricity where it should not be.

What Key Components Do I Need To Maintain An Electric Fence?

When setting up an electric fence, there are a few main components important to keeping your fence running properly, and using the correct capacity components will help in the long run.

The first step is to determine how many miles of fencing there are to power and choose an energizer, also known as a charger, with an appropriate joule rating.

For smaller areas with fewer fencing sections, 0.5-0.7 output joules are more than enough as the charger does not have to work as hard to push the current.

Using larger energizers than needed is also a good idea if you are in an area with lots of vegetation.

When choosing an energizer, most are low impedance energizers, which are ideal in the majority of situations.

A low impedance charger means that the pulses of electricity sent along the electrified lines are short-duration pulses, which is ideal for preventing vegetation from grounding out the fence.

Yet, for a charger to work, it needs to be paired with appropriately wired ground wires.

Ground Wires

Ground wires should be attached to at least 3’ feet of grounding rod for every joule of output on the energizer.

Energizers are usually powered by a normal outlet or connected to a battery if there are no nearby outlets.

While using an outlet offers a plug-and-play option, often one will not be available, and using a battery-powered setup will be necessary.

Some drawbacks of using a setup like this are the extra battery maintenance, limited battery life, and added costs.

Using a battery-powered setup can rely on charging through solar panels, making it an off-grid option and easy to move to new locations.

Conventional car batteries might work for a while but are not designed to be charged and discharged repeatedly.

A 12-volt deep cycle battery is a much better choice for an electric fence and is easily connected to solar panels or manually recharged as needed.

The physical structure of the fence should be sturdy and electrified lines should reach at least shoulder height to prevent cattle from climbing over the fence.

Grounding out is a common issue with fences, which means something conductive is touching one of the wire lines and breaking the electricity loop.

Grass, especially wet grass, is one of the biggest culprits of grounding a fence.

Trimming any tall grass in the path of the fence is the easiest solution most of the time.

Using sturdy fence posts and choosing a heavy-duty fence wire to carry the current such as barbed wire fencing or thicker gauge electric wires to carry the load, is a great way to keep the cattle contained.

Pairing a charger with a high enough joule rating to push the electric current through the fence and similarly rated electric fencing supplies will keep your livestock animals where they belong.

Check out other ways to keep cows away from bad food and dangerous items.

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Growing up amidst the sprawling farms of the South, Wesley developed a profound connection with farm animals from a young age. His childhood experiences instilled in him a deep respect for sustainable and humane farming practices. Today, through, Wesley shares his rich knowledge, aiming to inspire and educate others about the joys and intricacies of rural life.

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