Electric Power Fencing

Power fencing (electric fencing) is one of the cheapest and most effective scientific method for protection of crops and property from domestic and wild animal damages.

Electric power fence comprises of several strands of galvanized iron (G1) wires drawn along the perimeter. A high voltage electrical pulse is transmitted through the wires. Any animal/human being touching the wires gets a sharp, short, painful but safe shock. The animals hesitate to come in contact with the fence and thus becomes a psychological but active barrier and the animal/human being will not generally attempt to negotiate the fence again.

The electrical impulse is generated by an energizer. The energizer produces high voltage impulses of approximately 8 kv once in every 0.9 to 1.2 seconds. The impulse lasts for approximately 300 millionths of a second to 0.1 second and has a current of up to 10 mA. The current supply is generally available from 12V battery charged either by solar power or from a general electric supply system.

Advantages:

• Electric power fencing is easy to install and installation cost is low.

• It has a low maintenance cost.

• The system has a very long life.

• It can be designed to control the target species.

• It is portable and reliable.

• The system has recognised international standard.

• The system is eco-friendly.

• The system is safe and effective. Control is achieved by psychological means.

Care to be taken while installing the fence:

• Take survey of land/area to be fenced

• Select the right energizer.

• While installing the fence consider the soil conditions,

• Take into account the length of the fence,

• Proper selection of wire, insulators and other fence accessories, etc. should be done.

• Use quality components that offer little resistance for power flow as in wires or prevent leakages as in insulators to maintain proper voltage

• Use thinner wire, which offer more resistance.

• Take care that the voltage between live wire and earth should not exceed 200 volts.

• Adequate earthing to ensure movement of electrons through the ground is required.

• Suitable and optimal fence layout is done.

• Energizer should be fixed in the middle of the perimeter of the fence line.

• Energized gate is provided with an insulated handle for hooking and unhooking the wire.

The controller provides the shock sensation for keeping the livestock within/beyond the enclosure.

Proper data collection is an essential feature of a safe and successful power fence. Data on following aspects are collected during the site survey.

1. Where the system is to be used and the type of land it is to be used on.

2. The type of stock one is carrying or wish to fence off.

3. The size of the area one wishes to fence.

4. Whether the system is to be permanent or movable.

5. The type of wire one wish to carry the current.

6. The conductivity of the ground on which the system will stand.

7. The type of energizer that will best meet the needs.

8. The type of insulators to be used.

9. The most effective earthing system.

10. Types and locations of gateways.

11. Efficient insulation of wires from ground.

While selecting components and its design one should take cure of the following:

Energizer : To match the lines and length of the fence

Earth : To maintain the difference in voltage between the earth and live wire below 200 V.

Posts : Posts of any material can be used. End and corner posts must be strong and properly grounded. Use stays for corner and end posts.

Wiring : Use 12 gauge heavy hot dipped galvanised wire

• Keep one wire tightener for each line per section.

Joint clamps must for :

1. Energizer to fence

2. Fence to lightening diverter.

3. Fence to earth.

4. Jumpers

Lines : First line 15 cm above ground, other lines depending upon the combination of animals.

Insulators : Good quality insulators to prevent leakages Protection from

Lightening : Lightening diverters must be provided

Remove lid in case of storm.

Battery : a good quality battery should be used.

Charger : The charging unit must not be connected "on-line" to the energizer.

Power supply : Solar panels or state electricity supply

Safety : Warning sign to be installed in local and Hindi/English language

• Man trap should not be create

• Gap between power fence wires and overhead lines to be maintained as per State Electricity Board rules.

Installation :

A power fence installation involves:

1. proper grouting of end and corner posts to get required strength.

2. Clearing of vegetation along the fence.

3. Aesthetic layout of fence

4. Tight joints.

5. Proper electrical connections

6. Testing of fence

While installation of base unit is in progress, the vegetation clearance and post installation are initiated. If the new posts are being installed, the corner posts are installed first. A wire is temporarily drawn between the end posts to align the intermediate posts. Insulators are installed close to the posts so that wide gaps are not left for animals to get into the fence easily. Voltage is checked to see if it is between 5 and 8 kv. If voltage is less than 5kv, the fence line is checked for shorts or improper connections.

1. Unit Cost:

Cost of a power fencing system has two components:

1. Fixed component, i.e.the number and size of the components remain the same irrespective of the length of the fencing.

2. Variable component, i.e. the size and number of component vary with the length of the fence.

The total cost of long distance power fencing system is comparatively cheaper as the same set of fixed items are used over longer distances also. The unit costs for 1 ha, 2 ha and 3 ha farms using stone pillars are given here under:

Perimeter (approximate) of the area which requires fencing

1 ha – 440 m

2 ha - 660 m

3 ha - 770 m

Spacing between two poles –7.5 m (If needed wooden pole may be erected between 2 stone poles).

Cost of one stone post –Rs. 25.00

Cost of one wooden post – Rs.10.00

Cost of digging and fixing one pole – Rs. 3.00

Wire – G1 wire 12 gauge

Cost of 1 kg of wire – Rs. 24.00

Farm Safety