Testing of an Electric Fence

Plan for Troubleshooting

As we have previously mentioned, it is easier to test your fence if it is in sections that can be isolated. Some modern energisers include a remote fault finder (or you can buy a separate one) to track faults. A remote control unit, either hand-held or in the energiser, can be used to turn the faulty section off, so you don’t need as many switches on the fence to isolate sections.

For example, if the fence leads in four different directions from the energiser then there should be four main sections. Connect each section to the main feed line through an isolating switch. If possible, connect isolating switches at every branch in the fence.

If one section stretches for many kilometres then it should be divided approximately every 200 metres in intensive coastal situations and up to two kilometres in less intensive areas. It is best to do this at the end of a strain rather than an exact 200 metre or two kilometre distance.

It is also a good idea to have the live wires on all the fences on gate breaks or cut-out switches. For example, on the three wire cattle fence, both top and bottom wires are live. If the wires are kept separate and insulated from one another all the way along the fence, it is possible to switch either one off.

Fence Voltage

The fence voltage (volts) gives you some idea about how strong a shock can be delivered to an animal. The strength of the shock also depends on how far the animal is from the energiser and the moisture content of the soil. The legal maximum for an energiser is 10,000 volts and 3,000 volts gives satisfactory performance.

Voltmeters

We recommend you buy a good digital voltmeter or fault finder designed to test electric fences. You can use it for finding faults and also for finding out about the efficiency of the earth system by testing the voltage between the live wire and the soil.

Finding a Fault

Many things could cause a fault in your fence. You need a voltmeter or fault finder designed to help you detect any problems in an electric fence.
Include the following in your maintenance and trouble shooting procedure:

• clear the fence line of any plant growth, including grass
• check for slack or broken wires
• check battery terminals and water levels
• isolate sections and test each section of the fence for drops in voltage.

You might find the following flow chart useful if you have a problem with your fence.

Test Each Section

Connect a fault finder according to the manufacturer’s instructions or connect a digital voltmeter between the live wire and the earth. Switch each section off in turn using strategically located cut-out switches on the fenceline. The voltage shows a marked increase when the faulty section is switched off.

Once you have found the faulty section you can further localise the fault by switching off various parts of that section and then determine which wire has the fault by switching off each live wire in turn.

Hint: Connect the earth wire to the voltmeter before you connect the live wire.

When you are working on a particular section, switch off the other sections and use the voltmeter on the fence itself. After that you need to have a close look at the parts in the faulty section.

Testing Your Earth

• turn the energiser off
• heavily short circuit the fence at least 100 m from the energiser. You can do this by laying several steel stakes or lengths of pipe against the fence. Turn the energiser back on
• using your voltmeter, check the fence is dead
• insert the voltmeter’s earth stake into the ground at the full extent of the lead, and hold the hook against the last earth peg
• the tester shouldn’t read more than 200 volts. If the reading is higher you need better earthing. Either add more earth stakes or drive the stakes into an area of damp ground.