Nevada County Picayune and Gurdon Times Newspaper Archive

Hot Weather Poor Conductor Of Electricity

It's no shock to livestock producers that electric fences don't work very well when it's hot and dry.

"Dry grass and soil aren't good conductors of electricity," says Dennis Gardisser, agricultural engineer for the Cooperative Extension Service, University of Arkansas.

Gardisser says producers use electric fences because they're relatively cheap and they're easy to put up. Some fencing systems are portable, which makes it easier to do controlled, or cell, grazing.

"During hot, dry weather, when there's the least amount of forage, producers can rotate cattle from one section of pasture to another. It allows more efficient use of forages, and it gives one part of the pasture time to recover.

"Electric fences allow you to control your livestock."

Unfortunately, says Gardisser, electric fences lose some of their shock value when they're needed most when cattle are sticking their heads through the fences, trying to reach greener pastures.

Gardisser explains that electric fences work by transferring an electric field from the fence, through the animal, to the ground. "If the animal is standing on dry earth, it's difficult to get much of charge, because the ground is such a poor conductor.

"You can improve the fence's performance by making sure the system's charger is set up properly," he said. "The charger has two attach points, one negative and one positive. A wire from the negative point goes out to grounding rods. You can't use just one ground, or all of the electricity will be pulled to one area.

"I recommend at least three galvanized grounding rods be interconnected to a ground pole for each charger," Gardisser said. "At least during dry weather."

Only one grounding rod might be necessary during the rainy season, because wet soil and foliage are excellent conductors of electricity. A low energy charger, or even an improperly installed charger, might provide an adequate charge if the soil is wet.

"Something else you can do is run a wire diagonally from the hot wire to another wire on the fence pole and then tie both of the wires to a ground," says Gardisser. "When the animal sticks it's head through and touches both wires, it doesn't matter if it's standing on dry ground, or rubber cement for that matter. The circuit is completed and the animal is shocked.

"The key is to get a ground, either through the animal or other wires that are part of the fence."

Gardisser says debris and grass must be kept away from hot wires. "First of all, anything that touches the charged wire drain off some of the electrical power. Further down the line, there'll be no charge left.

"There's also the danger of an electrical spark setting off a fire if the hot wire touches dry grass."

Gardisser says a lightning arrester should be installed to protect fence chargers from lightning strikes. "That electronic charge is trying to find a route to ground. The arrester allows any big buildup of energy a route to ground before it reaches the charger."

Of course, you don't want to go out in a field during a thunderstorm and turn yourself into a lightning rod. And you especially don't want to grab an electrified fence. "You'll get a surprise," says Gardisser. Perhaps your last.

For more information about pasture fencing, contact your county office of the Cooperative Extension Service, University of Arkansas.