Electric Fencing for Snails

In November a query came in for an environmental solution to prevent slugs and snails from feeding on valuable plants. The object was to exclude them from raised beds without the use of poisons or chemicals.
After some thought I suggested using two lengths of the insulated cabling used in pigeon systems glued onto the brick risers. One cable used as the live wire and the other the earth. These were glued about 3 cm from the top of the boards. They were to be glued adjacent to each other so the wires were 1 cm apart. This meant the slugs would not be able to climb up the perimeter walling without touching both wires. A small 9v Electric Fence energiser was attached to the wires.
After installation a physical search for slugs already inside the bed was carried out and the unit switched on. A slug was seen to attempt entry and retreated from the wire without visible injury or side-effects.

The customer has reported that the level of slug damage this year was negligible and the cash return has been greatly increased due to the lower number of discarded blooms due to slug damage.

Electric Fencing was once snubbed in equestrian circles, everyone who owned livestock knew the basic rules: cattle and sheep needed to be enclosed with electric wire, but horses were best off behind wood planks, poles or hedges.

With the advancements and improvement in fencing technology in the last ten years that has outstripped the advances made in the previous sixty years and electric fences now come in forms well suited for horse properties. Modern electric fencing is the choice of a growing number of horse owners, who find that many of the old opinions that electric fencing is painful, unsafe, expensive, unreliable and difficult to maintain no longer hold true.

Safety is, of course, the foremost concern in any fencing decision. But what exactly constitutes a safe fence can become a complicated question. In some ways, horses are among the easiest animals to keep secure: They are domesticated and if they have all the food, water, shelter and friends they want, most horses aren't likely to try to leave their familiar surroundings. On the other hand, horses do pose a special challenge if it is determined to escape. Short of a 3 metre concrete wall, not much will hold in a 500 kilogram animal. You are after all simply fencing in the desire, the stronger the desire to escape - the more robust the fence needs to be.

Electric fences offer a barrier that horses respect, and the newer materials and erecting techniques that are lighter in construction and designed to flex and have a "rubber band" effect. This ability to yield under pressure is less likely to injure a kamikaze pilot or aspiring Houdini.
Touch an electric fence once and you'll know why it works; it's not very painful -- about the equivalent of a sharp slap -- but you'll remember the sensation, and you won't want to repeat it anytime soon. Horses, too, learn quickly that they don't want to bump, push through, rub against or chew on electric fences.

The energizer is designed to send out a high voltage (about 6000volts), low amperage (about 100 milliamps) electrical charge for a very limited time (about 1/300th. of a second.) every second. Compare this with two other scenarios.

1. Static Electricity when you touch a door, about 20000 volts at 5 milliamps for 1/1000th. of a second, unpleasant but not lasting.
2. Mains Electricity. 220volts at 13 Amps and constant, unpleasant and regularly causes death.

This sting (similar to a "thwack" from a riding crop) is what creates a psychological barrier within the horses' brain and it is this that fences him in. A fence with a voltage as low as 2000v is able to create an impression with a horse but this low voltage has other problems. Horses' hooves and hair are insulators so 2000v will be insufficient to bridge the insulated gap (particularly if they are on dry ground). A more viable fence should run at 6000 volts to be effective. Never a truer word may be spoken than "A wimpy energizer gives you a wimpy fence. " This higher voltage will also help when the horse has a blanket (a very good insulator) but a second line aimed at the horse's knees will be as effective. Utilizing bait on the line will also work.

Animals are the intended targets of electric fences, but anything else that comes in contact with both fence and ground will also complete the circuit. Very small items, such as blades of grass, allow a small amount of power to travel from the fence to the ground rods, but not enough to drain the entire system. (It's like a series of small holes in the fire hose, allowing some of the water to dribble away, weakening the pressure in the hose.) A short circuit occurs when an object, such as wire wrapped around a tree, reroutes all of the power from the fence to the ground system. Beyond the tree limb, the charge left in the fence is reduced to zero.

There are a wide range of conductors available in the form of standard wire, poly twine, tape or rope. The first consideration should always be the conductivity. This is quoted in Ohms/meter (or Ω/m). The lower this figure is the better and should be linked to the price of the material.

To illustrate this; an energiser capable of charging a fence 9 klm long with a conductor of 0.15 Ohms/meter will only be able to charge a fence 1.5klm long when using a 10 Ohm/meter conductor.

The physical format of the conductor you select is up to personal preference. There is a lot of research results available showing that horses see different materials just as well as if not better than humans. In my experience they are fenced in by plain wire just as well as tape and although there are reports of horses getting torn to shreds by wire these are more likely to be with barbed wire. (Barbed wire should not be used with electricity.)

First Day.

As my first post I'll simply introduce myself and leave it at that.

Spent most of my life in Zimbabwe until Mugabe made an absolute arse of himself and ruined a great country. Emigrated to the UK and I'm now a citizen of Mud Island.

I run an Electric Fencing company that is expanding reasonably rapidly. I will be mainly concentrating on that angle of my expertise.