Fault finding on an Electric Fence

Searching for problems in an electric fence is basically a step-by-step process. An adequate tester is essential or you are guessing – the only realistic alternative is to use your hand and I assure you – it hurts. A tester that shows if a fence is running at 6000v or more is far better than those on the market with a single LED light that only shows if there is a minimum of 2000v. This is an absolute minimum and the fence may only be 2100v which is not adequate for nearly every application.

To determine if the fault is with the fence or the energiser…

  1. Turn off energiser.
  2. Disconnect ground wire and the fence wire – there are now NO wires attached to the energiser.
  3. Turn energiser back on making sure the input power – mains or battery – is correct
  4. With fence tester, place the ground probe to the Earth terminal on the energiser and the metal loop on the tester to the positive terminal. The reading you get tells you how well the energiser is working without any other variables. If there is a very low voltage (under 3000v) or no voltage, then the energiser has a problem. If the voltage is high (greater than 6000v) then the trouble lies with your fence.

Finding a fault on an Electric Fencing System

If the fence is at fault, then there is a process of checking the fence with your tester as you go along

If the fence can be separated into several sections (by switches or by manually disconnecting parts of it), you can locate the problem by beginning at the fencer and progressively turn on sections of the fence. When the voltage suddenly drops you can assume that the problem is in the section most recently connected.

1.     Walk along the fence looking for any point where the energised wires touch ANYTHING not plastic, the soil, grass, trees, leaves, wood, water, snow, a steel post or steel wire – ANYTHING.

2.     On tensioned wire fences, check the wires at braces to see if they are touching a hot wire.

3.     Look for damaged/cracked insulators.

4.     If the conductor runs close to a wire fence the power may be arcing into that fence – move it a bit further away.

If you have a Fence Scout II you can simply touch the fence with the Scout at various points along the electric fence. The Scout will tell you at each point which direction to go in to locate the problem. Move in the direction indicated, testing as you go and you will arrive at the problem.

Using a Short wave radio here helps. A small AM/SW radio is an invaluable tool. Set off-station it receives the radio signals emitted by a short circuit in the fence line and the pulse of a fence fault is registered as a “click” – these get progressively louder the closer you get to the fault.

Testing the Earth System

To test an Earth Spike installation, firstly short out the live fence line to ground, either with a metal stake or by laying the fence line on the ground for about 100 metres and at least 30 metres away from the energiser.

Switch the energiser ON.

Measure the voltage between the GROUND and the Earth Spike with a digital meter If this is above 200 volts the earth installation is inefficient. Check the soil/water/metal contact or increase the number of Earth Spikes. If you do not have a digital tester then place your hand on the ground and touch the earth stake with the other. If you feel a tingle then the system is inadequate.

INDUCTION
A phenomenon known as induction is common with electric fences. This is the transfer of electricity from an electrified wire to a non electrified wire or gate without the wires physically touching each other. This is often mistakenly blamed on insulator leakage. This phenomenon is also more common in areas where the air is damp such as in conditions of fog. As this phenomenon is a quirk of nature it cannot be stopped from occurring. However, to avoid receiving shocks caused by induction on non electrified fences and gates etc. you can “ground out” the offending fence by connecting a ground wire to all wires on the non electrified fence. Push the end of this wire into the ground as far as possible and this will send all the offending voltage into the ground.

Energiser not working No input energy from mains or battery – change battery, check fuse.
Energiser Faulty – Disconnect leads and run Energiser test
Power not getting to the fence Poor Earth System-Run a test on your earth stake
Faulty lead-out high voltage cable – disconnect from the fence and test.
Poor Earth System Old and rusty earth stake – rust is a poor conductor.
Inadequate soil-stake contact for the size of the energiser – Add extra stakes
Dry or sandy soil – wet the soil or move to permanently wet soil
Furthest extent of your fence is more than 500m from the earth stake. – Add a further earth system with a return wire at that point
Power high at the start but drops off rapidly along the fence Broken filaments in the conductors restricting the flow of electricity
Poor joints between conductors – use steel connectors
Power good at energiser but poor in the fence Check your Earth system
Fence line is touching something – remember it must touch nothing but plastic
Vegetation touching the conducting wires
Conductors touching wood or steel post
Conductor wrapped around a tree at the end of the fence
Conductor dangling on the ground
Broken Insulators – power arcing to steel screws.
Poor connections in the line
I get a shock from the Earth Stake. This is a clear indication of a faulty earth system.
Lead out cable and earth line running too close to each other causing an Inducted current
Separate the live and earth cables by at least 50cm.
There is a direct short to earth
I get a shock from a metal gate or fence not connected to the Electric Fence Caused by an Induction current. Wires too close to each other- move them apart.
Earth out the metal section not part of the fence.

About admin

Agrisellex association with Electric fencing began 31 years ago in Central Africa where electric fencing was used to assist farmers, wildlife conservation entrepreneurs to control all aspects of African wildlife. We moved to the UK in 2000 and have become involved in all aspects of English Electric Fencing over these 13 years. Agrisellex has a long association with horizont Agrartechnik gmbh. This German company has been producing Electric fencing products for 60 years and is synonymous with German quality. Find us on Google+
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2 Responses to Fault finding on an Electric Fence

  1. Very useful info, many thanks :)

    chris davies

  2. Fantastic blog you have! I’ll keep keeping an eye out for more of your posts in future.

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