How to Properly Ground an Electric Fence (Safely)
The grounding system of your electrical enclosure is one of its most essential elements. Without a proper grounding system, your fence will be neither safe nor effective. With an optimized grounding system, you can expect exceptional performance from your electric fencing.
What is the Grounding System?
Your electric fence works as a closed circuit. A closed circuit means that the fence must have a positive terminal and a negative terminal. In other words, it must have a low resistance path for the return of the current to the charger’s ground terminal. The larger your enclosure and the more powerful your charger, the more extensive your grounding system must be, which usually means incorporating more grounding rods.
How Does Grounding Work?
When an animal touches the fence, the circuit must still be completed for the animal to receive a shock. The shock occurs via grounding. When an animal touches the fence, the current from the fence travels through the animal and into the earth. The moisture in the ground then allows the current to be conducted back to the grounding system to the charger’s grounding terminal, completing the closed circuit.
What Factors Can Impact the Effectiveness of a Grounding System?
Because soil itself is not particularly conductive, a lack of moisture can impede your grounding system. There are several ways to combat low-moisture or less conductive soil:
- Additional grounding rods;
- Choosing a more appropriate site for the grounding system; and
- Opting for alternative grounding methods (live/ground, for example).
Traditional grounding is the easiest option. But if you have concerns that the site’s soil will not be conductive enough, it may be worthwhile to consult with a fencing expert. The expert will determine which of the above alternatives might be best suited for your electric fence.
What Types of Grounding Options are Available?
Here are a few of the grounding options available for electric enclosures:
An all live system is the most common. It is one of the simplest methods and applicable to most sites where the soil is damp or conductive. The electric current flows from the wires to the animal, back into the ground, as described above.
If the soil isn’t conductive enough, some manufacturers construct fences with both live wires and ground wires. The live wires and ground wires allow the current to flow from the live wire into the animal and then into ground wire, to the grounding rods. It requires the animal to touch both wires at once.
Bentonite Salt Ground
In arid, non-conductive conditions, the fence may require a bentonite salt ground. A mixture of salt and bentonite surrounds each grounding rod. Salt attracts moisture, which then acts as a conductor. Bentonite is a type of clay derived from volcanic ash. Its function is to absorb and retain the moisture drawn to the site by the salt. When using a bentonite salt ground, stainless steel rods are a necessity due to the risk of salt corrosion.
Bipolar fencing systems still have a grounding system but can still function when the soil is too dry or too frozen to be conductive. They feature sets of positive and negative wires; if the animal touches both a positive and a negative wire, they will receive a shock. This system is somewhat more complex to install, so it is generally only recommended in the most extreme cases of non-conductive soil.
Select the Right Site
Ideally, your grounding site should be at least 33 feet from other grounding systems (your house’s electrical grounding system, underground phone lines, underground powerlines). It should be isolated from the traffic that might disrupt the system, whether human or animal. You’ll want to frequently check your grounding system and make sure it’s accessible for maintenance. And of course, you want it to be in an area with conductive soil.
Install Grounding Rods
The number of rods you’ll use will depend on your charger and the size of your fence. The manufacturer’s manual for your charger, or your fencing supplier, will have relevant recommendations. The rods should be at least 6 feet in length. The rods should be ten feet apart if you are installing a traditional grounding system. The distances may be greater for a bentonite salt system.
At least 2-4 inches of the rods should remain above ground. Connect the rods in a series to one another, and then to the grounding terminal of your charger.