11 Common problems when testing electric fences | Troubleshooting Electric Fencing
Posted by Patriot Chargers on
1. Grounding
Most electric fence problems are caused by poor grounding. Why? An electric fence is an electrical circuit. The electrical current travels from the charger, down the fence line, through the animal, along the earth to the ground system and back to the charger. If the ground system is inadequate, the electrical current is reduced and the animal receives a weaker shock.
Tips -
• The ground system should be at least 33' (10 m) away from electric or telephone ground systems to avoid interference.
• Moist soil conducts electricity much better than dry soil. If possible, locate the ground system in a boggy area. In dry weather, wet the area around the ground system to keep the soil moist.
• Make sure there are a sufficient number of ground rods. See your charger’s user manual for recommendations. If in doubt, use at least three ground rods. Use more ground rods if your soil conditions are not ideal.
• Ground rods should be at least 6'6" (2 m) long. One long ground rod works better than several short ground rods.
2. Testing your ground system
Test your ground system regularly to ensure you are getting the most out of your electric fence.
1. Turn off the charger.
2. At least 330' (100 m) away from the charger, short circuit the fence by laying several steel rods (or lengths of pipe) against the fence. In dry or sandy soils, it may be necessary to drive the rods up to 12" (30 cm) into the earth.
3. Turn on the charger.
Note: Do not short circuit a fence-return (ground-wire-return) system by connecting the live wire to the ground wire.
4. Use a digital voltmeter to measure the fence voltage. It should read 2 kV or less. If not, add more ground rods.
5. Check the ground system by inserting the voltmeter’s ground probe into the earth at the full extent of the lead, and test the voltage on the last ground rod. The voltmeter reading should be no more than 0.3 kV. If the reading is higher than this, your ground system is insufficient. Add more ground rods, or find a better location for your ground system.
3. Faults
Faults are caused when the electric current leaks away from the fence down to the earth. This is often caused by grass, weeds or overhanging branches touching the electric fence. Broken insulators may cause a fault by allowing the electric fence wire to touch the fence post. Check your fence regularly using one of the procedures below.
4. Checking your fence
Using a fault finder is the quickest, most accurate way of locating a fault in the fence. Starting at the leadout wire, work your way along the fence taking readings at regular intervals. A fault will show up as an abnormally high reading. The electrical current flows towards a fault in the same way that water flows towards a hole in a punctured hose. A sudden change in current between one point and the next indicates a fault between the two points.
It is also possible to check for faults using a digital voltmeter. Isolate sections of the fence using cut-out switches and check the voltage in each section.
An AM radio can be used to locate a fault. Tune the radio between stations and drive or walk along of the fence. If the fence is OK, there won't be any sound. When the radio gets near a fault, you will hear clicking on the radio. As you get closer to the fault, the clicking will get louder.
If the fault is caused by a faulty insulator, mark it with non-metallic paint so you can locate it easily after you have turned off the fence.
5. Joins
Electric fence wire should be joined using a knot that allows the electrical current to pass through the wires. Here are some recommended knots:
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To join broken poliwire or politape, use a cigarettle lighter to burn away the plastic yarn in order to expose the stainless steel wire. Twist and join the wires together, then tie the poliwire or politape in a knot. The electrical current can then pass through the join. When inter-connecting fence wires at the end of a strain, use joint clamps. Using these clamps, instead of twisting wires together prevents arcing and greatly reduces voltage loss.
6. Undergate connections
When bypassing gateways, ensure that live wires are protected from damage caused by animal hooves, vehicles etc. Encase high quality, double insulated underground cable in a polythene pipe and bury at least 12 inches (30 cm) deep. Turn the ends of the pipe down to keep water out.
7. Animal training
To train animals to respect electric fencing one method is to use a small well-fenced holding paddock. Divide the holding paddock using Politape and a Patriot charger. Introduce the untrained livestock to the paddock. The animals will quickly learn to avoid the electric fence barrier.
8. Choosing an electric fence charger
Make sure your electric fence charger meets the requirements of your electric fence, refer to your Patriot installation manual for guidance. This will vary depending on the type of fence, the number of fence wires, how much vegetation is growing around the fence and the climate. Remember, if you extend the length of the fence by adding to the fence or subdividing it with temporary fences, you need to make sure your charger is powerful enough. If you use a more powerful charger, make sure you increase the number of ground rods in the ground system.
9. RFI (Radio Frequency Interference)
Many farms suffer from RFI (Radio Frequency Interference. This often results in poor radio reception and an annoying ticking noise on the telephone line. Patriot chargers are fitted with special components and advanced circuitry that significantly reduces the levels of electrical emissions that might otherwise affect adjacent electrical equipment. .
10. Mixing metals
Avoid using different metals in your electric fence. In damp conditions, when an electric current passes through the differing metals, electrolysis will occur. For example, using stainless steel ground rods and an aluminium leadout wire will cause problems. In a short space of time, the aluminium will disintegrate. If possible, keep the wire joints above the soil to improve airflow and reduce electrolysis. Seal the wire joints with thick paint, epoxy or tar to keep moisture away from the joint area. Use identical metals in your electric fence will avoid problems with electrolysis altogether.
11. Getting a shock from a fence post or gate?
Sometimes, induction causes a strainer post or metal gate, giving whoever touches it a nasty shock. To overcome this problem, staple a piece of wire onto the strainer post to interconnect all the fence wires. Bury the wire 3" (10 cm) into the earth. This will carry the unwanted current down to the earth. Because the interconnecting wire is positioned after the insulators, you will not be compromising the quality of the fence in any way.