Lightning and Electric Fences - How to Protect Livestock and Property
Lightning is an unavoidable threat to livestock, farms and ranches. Since most farm operations are located in areas where there’s ample pasture land and plenty of open space, farm buildings and even fences can attract lightning during stormy weather.
Protecting an electric fence from lightning strikes should be a top priority for ranchers, since a hit can destroy valuable electronics, kill livestock and destroy other property.
LIGHTNING PROTECTION: THE BASICS
To best protect an electric fence, advise your customers to follow all of these steps:
- Install a lightning arrester between the fence and the fence charger. Install one on every corner of the fence if possible. Keep these devices at least 50 feet from the charger.
- Add a Zareba® Storm Guard to any charger (1 joules or higher) to absorb any lightning that is able to move past the other devices. (Note: Storm guard is included with all Zareba® 100- and 200-mile chargers.)
- Disconnect all fence chargers prior to a major storm, if possible.
WHAT DOES LIGHTNING DO TO AN ELECTRIC FENCE?
Lightning will always seek out the path of least resistance on its way to the ground. As such, fences with hundreds or thousands of feet of metal wiring in them make excellent conduits for lightning.
Aside from direct strikes, lightning can also induce voltage on to a fence line. This can happen even when lightning strikes several miles away from the fence.
The danger, however, is all the same.
As the energy from induced lightning travels along the fence, it seeks out a path that will deliver it into the ground while expending the least amount of energy. In the case of an electric fence, that path will be through its ground rod system, which is on the “opposite side” of the fence charger. That means if induced lightning hits an electric fence, it must travel through the charger to get to the ground rods. This route can destroy the fence charger in the process.
The other possible route for induced lightning to reach your fence charger is through a utility line. With that kind of strike, the electrical energy will travel through the utility line to the electrical outlet and into the device itself. This surge of energy can also destroy the charger.
Though rare, direct lightning strikes on a fence are also problematic. They are sure to cause a fence charger failure no matter what precautions a rancher makes.
Physical damage from lightning to the fence is very rare, however. That being said, damage can occur if the energy arcs unexpectedly from the fence to another object. In fact, the energy from a lightning bolt can be strong enough to vaporize metal. That sort of surge can spell trouble for nearly any component of an electric fence.
LIGHTNING SAFETY FOR LIVESTOCK
Livestock left in a pasture during an electrical storm are usually safe, but a particularly intense storm can decimate a herd. The biggest problem is that cattle tend to congregate under trees during storms. Since lightning often seeks out and strikes the tallest object it can find, livestock under trees are at an increased risk for injury.
To protect animals from lightning:
- If possible, move livestock inside a grounded building to protect them from direct strikes.
- Only allow trees to grow in rows on a pasture, rather than in groups. This spreads out the chance for strikes, and theoretically limits the number of livestock injured.
- Also note that certain trees with large root systems tend to be hit more often than those that don’t.
- Place metal feeding troughs in low-lying areas, rather than on the top of the hill.
- Further, consider insuring the livestock for lightning strikes.
LIGHTNING ARRESTERS AND OTHER LIGHTNING PROTECTION
A system’s fence charger is the most valuable component of a fence, so take steps to protect it.
To protect do so, prepare in advance by installing equipment that isolates the charger and discharges or absorbs lightning. These can include lightning arrestors, lightning diverters and surge protectors.
It is best to use a combination of these devices for maximum electric fence lightning protection.
|LIGHTNING PROTECTION PRODUCTS|
|PRODUCT||Lightning Arrester||Storm Guard|
|SEPARATE GROUND ROD NEEDED?||Y||N|
|REPLACE AFTER STRIKE?||Possibly||Y|
|INSTALLATION TIME||Hour (including adding ground rods)||Minutes|
|PROTECTIVE FUNCTION||Transfers lightning energy into the ground. Use in conjunction with Storm Guard.||Attaches to fence at ground posts to absorb energy from lightning strike. Last point of contact. Protects charger.|
Lightning Warranty for Energizers
Zareba® offers full lightning damage coverage on all chargers under the two- and three-year limited warranties. Make sure your customers know to register their charger online to activate and extend this warranty.