Trouble Shooting

Trouble Shooting Electric Fencing Faults

A Step-by-Step Approach to finding Faults

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 alternative is to use your hand and I assure you - it hurts. A tester that shows if a fence is running at 6000v 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. 
A small AM/SW radio is an invaluable tool. Set off-station it receives the radio signals emited by a short circuit in the fenceline and the pulse of a fence fault is registered as a loud "click" - these get progressively louder the closer you get to the fault.


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

1/. Turn off the energiser.
2/. Disconnect the earth or wire going to ground AND the live fence wire - there are now NO wires attached to the energiser.
3/. Turn energiser back on. 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. (The lights on the tester get paler as the voltage goes up, often quite difficult to see particularly in bright light. The highest light seen will be the reading - not the brightest seen) )
4/. If there is a very low voltage (under 1500v) or no voltage, then the energiser has a problem. If the voltage is high (greater than 6000v) then the trouble lies with your fence. Most energisers put out between 5000v and 8000v when there is no load (i.e. no fence hooked up).

Testing an Electric Fence Energiser


 If a Voltmeter is not available you can use a screwdriver as a "gross check" for voltage output. Use the screwdriver to draw an electrical arc between the two terminals. The length of the spark is indicated below. This is by no means accurate but will indicate if your energiser's output is reasonable

  • The 220v energisers should jump a gap of 3-5mm (1/8 - 1/4 inch)
  • A 12v battery energiser should jump a gap of 2-4mm (1/16 - 3/16 inch)


If the energiser is faulty and you have a battery unit you need to learn if the battery or the energiser is the problem...

1/. If it's a 12 volt energiser carry the energiser to a nearby vehicle and attach the input cords carefully to the vehicle's battery.
2/. If the energiser now works, then your energiser's battery needs to be recharged or replaced.
3/. If the energiser does not work, then you should call Agrisellex re. repairs.


If the energiser is faulty and you have a Mains unit you need to learn if the input power or the energiser is the problem...

1/. Check there is power in the 220v plug point
2/. Check the 13 amp fuse in the plug


Testing for a Faulty Earth.

1/. Many problematic fences may be attributed to an ineffective earthing system. This is particulary prevalent in drier or sandy areas.
2/. Place a steel rod agains the fence and touching the ground to simulate an animal touching the fence. Insert the tail of the tester into the ground and touch the line going to the earth terminal of the energiser with the tester. If you read more than 200v then your earth system needs sorting out. If you don't have a tester then place your palm on the ground and touch the earth wire with your other hand.
3/. If you feel a tingle your earth is faulty.
4/. A mild steel iron rod will build up rust over time and as rust is a poor conductor the rod will become less effective. Use Galvanised steel, Stainless steel or copper rods.


Finding a fault on an Electric Fence

If the fence is at fault, then you must find the fault(s) and fix them. Here's how to start this process:

1/. If you have a Fence Scout, simply touch the fence with the Scout at various points along the electric fence(s). The Scout will tell you at each point which direction to go in to locate the problem. Move in that direction testing as you go and you will arrive at the problem. Note: The directional arrow of the Fault Finder is not accurate with net.


Using a Fence Tester

Using a Fence Tester


If you have a 10000v or Digital Tester. (Using a Short wave radio here helps.)

1/. Disconnect at the fence the Lead-out Cable (High Voltage Cable) that connects the energiser to the fence and check at the end of this cable - that will tell you if the current is actually getting to the fence.
2/. Walk along the fence looking for any point where the energised wires touch ANYTHING not plastic or insulated, the soil, vegetation - grass or leaves, wood, water, snow, a steel post or steel wire. On tensioned wire fences, check the wires at braces to see if they are touching a hot wire.
3/. Look carefully for damaged insulators. A crack in the plastic will allow energy to track to earth.
4/. If the fence can be separated into several sections (by switches or by disconnecting parts of it), you can locate the problem by beginning at the fencer and progressively turn on sections of the fence. 5/. When the voltage suddenly drops you can assume that the problem is in the section most recently connected.
6/. Take readings along the fence, if the fine wires in the rope/tape are damaged you should be able to pick up where they are broken and repair them there.


Fault Finding on Poultry Nets.

1/. If the voltage drops below 3000v on the net, you need to turn off the energiser and unhook the net from the energiser.
2/. Test just the energiser by itself as outlined above - If the voltage is 5000v or higher on the energiser the problem is in the net.
3/. The most common problem is that the lowest 'hot' strand has been caught around one of the metal spikes on the posts and is shorting it out.
4/. The net must be at least 2" away from anything metal (metal posts, existing fences, spikes on support posts) to reduce te possibility of arcing.
5/. On Poultry Nets, the bottom hot wire can slip off of the plastic portion of the end posts down onto the metal spikes. This will cause a dead short and no energy will be on the fence. Unhook the energizer and slide the hot wire back onto the post.
6/. Hook energizer back to the net and test.


Induction Current

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 caused by magnetic fields being set up and collapsed by the pulsing nature of an electric fence current. These magnetic fields will generate a current in an adjacent wire even if it is not touching it and draw energy off the fence itself. This is often mistakenly blamed on insulator leakage. Common where the earth line and the fence line ar run next to each other out of a building. Simply separate the wires by about 30cm.

This 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 Troubleshooting. 


Fence Troubleshooting.





Energiser not on or no voltmeter reading across energiser output terminals when disconnected from fence.

  • Mainline power outage
  • Blown fuse on input circuit
  • Energiser switched off
  • Dry cell batteries dead, wet cell batteries discharged
  • Terminals corroded
  • Faulty energiser

Energiser on but low voltmeter reading across energiser output terminals when disconnected from fence.

  • Energiser switched to low setting
  • Weak batteries
  • Terminals corroded

Energiser connected & operating but no voltmeter reading on fence.

  • Ground-return wire disconnected or broken
  • Feedwire terminals corroded, disconnected or broken
  • Broken live or ground-return wire on fence

Low voltmeter readings at several places on fence.

  • Energiser on low setting
  • Energiser inadequate for length of fence
  • Weak batteries
  • Terminals corroded
  • Ground system inadequate
  • Soil too dry.

No voltmeter reading or low reading at one location on fence.

  • Broken wire
  • Dead short across wires
  • Broken or disconnected jumper wire
  • Disconnected or deteriorated ground rod

Voltmeter reading on one wire higher than another or no reading from one live wire to ground-return wire or soil.

  • Broken or disconnected fence wire
  • Broken or disconnected jumper wire
  • Broken or disconnected ground wire
  • Broken or faulty insulator
  • Ground rod deteriorated
 Current is found on the earth line or on other wires close to the fence.
  • Caused by current being transferred across the wires by induction.
  • Separate the two wires.

Radio, TV or telephone interference.

  • Ground system inadequate
  • Antenna too close to fence
  • Fence parallel with antenna wires or telephone wires