Underperforming energizer? It might be your earthing system

An energizer’s performance is only as good as the earth system that supports it. Older energizers are often upgraded to newer, larger units but the earth system can be overlooked.

For an energizer to shock effectively it requires a well set-up earth system that complements the energizer output to complete the circuit properly. Investing money in an energizer for reliable stock containment could be wasted if the earth system isn’t suitable.

To test your earth system’s voltage, a digital voltmeter should be used on the last earth rod furthest from the energizer, when the fence line is shorted out. The voltmeter reading should be no more than 300v or 0.3Kv.

Australian Farmer Earthing an electric fence

A poor earth system can result in the energizer providing a much weaker shock on the fence line than required, leading to stock breakouts. A less obvious repercussion of poor energizer earthing is stray voltage. This occurs when the energizer’s earth system is not sufficiently gathering the electrons returning to the energizer to complete the circuit and send the shock. These electrons must earth and will attach to other metal objects resulting in shocks off metal sheds, feed silos, cow shed bails and gates.

For the most effect way to earth an energizer use stainless steel or galvanised earth rods to avoid corrosion. The rods should be spaced 3 metres apart with one continuous cable from the earth terminal to the last earth rod. One earth rod is needed per 3-4 output Joules with a minimum of three rods for any mains unit. The location of an earth system is important – they can be up to 1000m away from the energizer but must be a minimum of 10m away from other earth systems (e.g. house mains) to avoid lightning strike jumping. An earth system should be located in spaces which are easy to find for checking or upgrading but are out of the way of stock and traffic movement. Damp or wet areas are preferred and against the southern sides of a shed or around effluent ponds are recommended sites.

Ground Earth Return Diagram

Y-posts or old pieces of steel often do not penetrate deeply enough into the soil to find moisture, they’re also prone to rust which prevents good transfer of electrons, and they can struggle to get a clean connection between the underground cable and the earth rod.

A Speedrite Earth Kit contains three earth rods and clamps that are made from solid galvanised steel that ensures a clean, rust-free connection between the energizer and earth system. For less conductive soil you may want to consider a Speedrite Bentonite Earth Kit, available from your local CRT Store.


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