An electric fence system that is not properly grounded will not perform up to its maximum potential and may not adequately contain the livestock or keep predators out. Michigan State University Extension recommends considering are three main factors when determining how to properly ground an electric fencing system:
- The output capacity of the energizer
- Conductivity of the soil
- Type of livestock or predators being controlled
An energizer must be properly grounded to realize its full potential. The larger the output of a charger, the more grounding rods will be needed. A general rule is to install a minimum of 3 feet of ground rod per joule of output capacity. A 15 joule fence charger will require a minimum of 45 feet of ground rod. These rods must be installed at least 10 feet apart from each other. The lower and wetter the ground they are installed in the better their performance will be. Most grounding rods are made from galvanized steel or copper and it is important that the type of wire used to connect the energizer to the ground rod be identical to the rod. Doing so will help to minimize the reduction of performance from electrolysis.
Sandy or rocky soils are not as conductive as loamy soils, so systems installed on these types of soils may need to be an earth return type of grounding system. An earth return system is one in which alternate wires in the fence are utilized as ground wires. Charged wires on a system need to be connected back to the output connector on the energizer and earth ground non-charged wires need to be either connected back to the ground terminal on the charger, or connected to ground rods in the fence lines. Experience at Michigan State University’s Lake City Research Center has shown it is better to place ground rods that are in sandier soils below roof eves on buildings to get the maximum amount of moisture possible.
“The depth of the rod also makes a big difference on dry years, we have some rods that we have had trouble with that are in the ground 10 feet or more,” says Research Center Manager Doug Carmichael.
Sheep or goats are typically controlled better by earth grounded systems, where as all other livestock can generally be controlled without the use of the earth ground system. This is true, provided the soil isn’t sandy, rocky, or extremely dry as mentioned above.