Effective earthing of an Electric Fence is a perennial topic and needs to be well understood as many people still think you can skimp when it comes to adequate earth grounding. What we must all learn is the electricity must complete a full circle back to the energiser through the ground. Poor earthing will result in the reduced transfer of electrons from the ground back to the energiser invariably felt as a weak tingle or weak shocks.
The ground constitutes 50% of the electrical circuit but 90% of all problems originate at poor earthing, either at the earth stake itself or on the fence. Fortunately this is easy to rectify. Additional earth stakes may be added by driving them into the ground about 2m away from the existing stake and joining them together. Copper, Stainless Steel or Galvanized steel rods are best. Mild Steel is a poor option as it will react with the ground chemicals and rust. This layer of Rust will create a poor conducting barrier between the metal and the ground. This should only be used as a temporary measure. All rods should be located in permanently moist soil, under the building eaves, in a river bed, below a dripping tap or in an irrigated flower bed. In particularly dry weather the soil around the stakes may be watered. A legal stipulation requires that an electric fencing earth post to be more than 3m away from a household earth system.
Poor electron transfer from the fence back to the earth stake is less easy to rectify. If the fence extends over 500m in a straight line away from the main earth post it will be necessary to add an additional earth line to the bottom of the fence and bury a stake at those intervals. Wire is a better conductor than ground so a ground rod approximately every 500meters will greatly increase the effectiveness of the fence. This connecting wire does not need to be insulated from the ground BUT must be insulated and separate from the live wires of the fence
A Earth Return Fence
In dry climates or where the soil is very sandy resulting in poor conductivity through the soil, it will be necessary to consider an Earth Return fence. This is where the fence is constructed from equal numbers of live and earth wires to remove the ground from the electrical circuit. The animal is required to touch both wires to achieve the desired effect. An earth post is still utilised to cater for current flow through the ground.
These measures will all contribute to maximising the potential of an electric fence and by improving its effectiveness, allow it to achieve its desired goals.