Whether you're an old specialist with a pair of fencing pliers for a right hand, or just learning the ropes of wood, wire and tape, there's always something to learn when it comes to livestock fencing. Jim Gerrish, of American GrazingLands Service LLC in May, ID, and Merle Mohr, Gallagher territory manager based in Mina, SD, shared their thoughts on the most common fencing mistakes they see.
1. Corner posts
Both Gerrish and Mohr cited this as their top mistake when it comes to fencing. And it applies to barbed wire, high-tensile or woven wire fencing.
“I see a whole lot of fences that are basically intact and the corners are already falling apart,” Gerrish says.
The main issue, he cites, is that people use undersized posts and don't set corner posts deep enough, particularly in sandy or other soft soils. A guideline he follows: “The depth in the ground should be equal to, or greater than, the height of the top wire.”
For example, if the top wire on the fence is 42 in. high, there should be at least 42 in. of post in the ground.
Post diameter depends on the strength of the fence. Gerrish says the lightest-duty fence, such as a 1- or 2-wire high-tensile pasture subdivision fence, would only need a 4- to 5-in.-diameter post. A 5-strand barbed wire fence, or 5- or 6-strand high-tensile fence, would use a 6- to 7-in.-diameter post. And for net wire fences, Gerrish prefers an 8-in.-diameter post.
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Keeping corner posts in the ground is the chief concern for Mohr. “A 10-ft. brace is the ultimate in making corner posts stay in the ground,” he says, favoring a “floating diagonal” bracing system, in which the angle brace is a 4-in. by 10-ft. post notched a half-inch into the main corner post. The other end is set on top of the ground opposite of the corner post.
Mohr also cautions fencers to be wary of using drillstem for corner bracing. Drillstem is the metal pipe byproduct of oil wells. Unlike wood, it has the potential to conduct electricity and lessen the efficiency of the fence (see miskate #7).
2. Post spacing
“We always tell people they're using way too many posts,” Mohr remarks. The practice stems from people's experience with barbed wire, he says, where the rule of thumb was 1 post spaced every rod length (16.5 ft.). In an electric-fencing system, posts can be spaced farther apart. Mohr spaces posts 80-100 ft. apart, about 50 posts/mile.
He suggests using a “stay” if posts are spaced 100 ft. apart. A stay is a shorter post that sits on top of the ground and holds wires up. Gerrish prefers his posts closer together, at 50-70 ft.
3. The right sized energizer
Undersized energizers are another common mistake, Gerrish says. His guideline: 1 joule of output per mile of fence, regardless of how many strands of wire.
It works well, considering a typical operation has several different types of fence: a 4- or 5-strand high-tensile perimeter fence and some 1- or 2-strand interior fences. If there is a total of six miles of fence, it will require a minimum of a 6-joule energizer.
“You're pretty well covered if you plan for 1 joule per mile of fence,” Gerrish says.
Mohr recommends using a low-impedance energizer, with a low-amp fuse. “The larger the energizer, the smaller the voltage,” Mohr says, because larger energizers are apt to power through more vegetation and short out. He considers 7,000-8,000 volts high for an energizer.
“Grounding is 99% of the electric fence,” Mohr states.
Gerrish uses the rule of thumb: 3 ft. of ground rods per joule of energizer output. So if the fence is using a 6-joule energizer, it would call for 18 ft. of ground rods. “Typically this would be three, 6-ft. ground rods, spaced at least 10 ft. apart,” Gerrish explains.
Spacing is key. Gerrish explains that a ground rod is essentially an antenna receiving electrons flowing through the soil and back to the energizer, completing the circuit. Ground rods can also interact with a given volume of soil. So if three ground rods are driven into the ground 6 in. apart, in essence they act as one ground rod because of the volume of soil they interact with.
Mohr points out that most people will put in three ground rods near the energizer. He encourages people to space ground rods throughout the whole network of fencing. It's especially necessary if the average rainfall of the fenced area is less than ideal for proper grounding.
Copper makes the best type of ground rod, but it is expensive. Which is why most fencing companies use an insulated galvanized lead-out wire on energizers. “If you have a copper ground rod, you need to run a copper wire to the energizer that it's grounding,” Gerrish says.
Likewise, if there's galvanized wire in the electric fence system, keep everything galvanized. Mohr strictly recommends nothing but 12.5-ga. galvanized wire, galvanized ground rods and galvanized connections. He notes, too, that a galvanized ground clamp won't have corrosion problems that a copper connection would have in six months.
5. Wildlife friendly
“When dealing with big game like elk and moose, rather than trying to build a fence physically strong enough to stop them, build a fence that's flexible enough to give with their movements,” Gerrish says.
He says building a fence with flexibility is more important than building enduring strength into a fence. When Gerrish relocated to Idaho from Missouri, the fencing was high-tensile electric on T-posts. Gerrish says T-posts were getting bent over and insulators broke off due to wildlife traffic. He replaced T-posts with PowerFlex fence posts and has had few problems since.
Another consideration is building a low-profile fence. On Gerrish's 2-wire range fences, the top wire is at 30 in. and the second wire is at 20 in. It is designed so antelope can go under wires at a dead run and low enough that elk will hit the fence with their legs and not the heaviest part of their body.
6. Gate openings
In an electric-fencing system, creating a gate system that conducts current is a challenge. Mohr recommends placing a floating diagonal brace on either side of the gate opening.
To keep the fence “hot,” he recommends trenching both insulated hot and cold galvanized wires 1 ft. deep under the opening. This may need to be deeper in high-traffic areas or low-lying wet spots, or shallower in less-used pasture settings. “The gate no longer needs to carry current, because you have your current going underneath the ground,” Mohr says.
“Putting a steel post anywhere into an electric fence is a big mistake, because you are then relying on the insulator to keep your fence from shorting out,” Gerrish says. He prefers the wood-plastic composite PowerFlex post or fiberglass. “No matter how good an insulator you get, eventually something's going to break or pop off, and you have the potential for dead-shorting.”
Do you have any fencing tips to add? Leave a comment below!
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