Gauge your electric fence needs
Electric fencing is a critical tool for most graziers.
In wet years, most electric fence systems can do an adequate job of convincing animals that the grass isn’t really greener on the other side, even if the voltage isn’t high.
In dry years, marginal electrical fence systems may not maintain adequate voltage. Holding animals in one paddock can be a real challenge when the grass is greener or longer on the other side.
Evaluate your electric fence system’s components by considering these basics.
The energizer/charger is the “heart” of the system. This isn’t the place to cut budget corners.
Size the energizer/charger to handle your current fencing system, plus room for growth.
Keep in mind that over the years, graziers tend to significantly increase the amount of electric fence, with expanded pasture acreage, internal divisions, or sometimes both.
Check the fence voltage to make sure it carries adequate voltage to deter livestock. You might consider these voltage levels:
• 1,600 to 2,000 volts for cattle
• 3,000 volts minimum on electric netting for sheep and goats
• 4,000-plus volts on high-tensile fence for sheep and goats.
Some sheep and goat producers maintain 7,000-plus volts on their fences.
One way to evaluate chargers/energizers is to look at output in joules.
Also, remember that when a product is advertised by the miles of fence it can energize, this includes one wire — not multiple wires.
• Weather conditions can affect electric fence performance.
• Make sure the charger matches the amount of amount of fencing you have.
• Inspect fence wire condition to make sure that the charge runs at full capacity.
Don’t overlook ground rods
Full energizer capacity can’t be utilized without a good ground system. In a dry year, it’s critical to have the correct number of ground rods, properly spaced, to keep enough voltage on fences.
A general rule of thumb says to install a minimum of 3 feet of ground rod per joule of energizer output capacity.
For example, if I have a 15-joule energizer, this requires 45 feet of ground rods: generally 6- to 8-foot lengths of galvanized or copper rods.
This energizer would require six to eight rods, depending upon whether 6- or 8-foot ground rods are used.
If copper rods are used, use a copper wire from the energizer to the ground rod. If different metals are mixed, electrolysis can reduce effectiveness of the grounding system.
Ground rods should be driven in to their full length. If rocky soils don’t permit this, drive them in at an angle.
Ground rods should be at least 10 feet apart, and 40 to 50 feet away from other grounds. Try to locate them in areas are likely to stay moist.
Northern exposures under building drip lines often work well. In drought situations, it may be a good idea to water your ground rod areas to increase fence effectiveness.
What about the wire?
As wire diameter decreases, there’s more resistance to push electric current around the fence.
Polywire is very handy stuff, but shouldn’t be used to carry the charge long distances.
Use high-tensile wire to carry the charge and for perimeter fencing. Use polywire for internal paddock divisions.
Check to make sure the wire’s galvanized coating is intact. Rust is your enemy.
Lewandowski is with Ohio State Extension in Athens County.
This article published in the March, 2010 edition of AMERICAN AGRICULTURIST.