Since its invention by JVA's co-founder and Director in 1991, the Directional Electric Fence Fault Finder has revolutionised the way people monitor their electric fence all around the world.
Like with any product, there are tricks to get the most "bang for your buck", and we want to share ours with you! If you have any additional tips to add, please comment them below.
JVA Fault Finder Tip # 1. The difference between Voltage and Current.
Electricity can be compared to water: To move water along pipes we need to push it with a pump which creates pressure. To move electrical current (Amps) along a wire we need to push it with an energiser to produce electrical pressure (Volts). If you had a large leak in a water pipe there would be a flow of water from the pump which produces the pressure to the leak. A short circuit in an electric fence is like a water leak. By following the current (Amps) flow the JVA Fault Finder will lead directly to the fault.
JVA Fault Finder Tip # 2. Know your electric fence.
Every electric fence is different, influenced by a range of variables including the type of wire and insulators used and the length of the fence. Even the same fence can change from day to day with changes in weather and vegetation. Not every electric fence is perfect. So it is good to know what is ‘typical’ or ‘normal’ for your fence. Take the JVA Fault Finder and take regular measurements (readings) to learn what is ‘normal’ voltage and current on your fence. This will allow you to know the acceptable voltage required to keep your livestock in and when it is time to fix the fence.
JVA Fault Finder Tip # 3.
To find multiple faults on the electric fence, use these rules:
1. Start close to the energiser, where the lead out connects to the live wires and work away.
2. Always follow the wire showing the highest current (Amps) reading.
3. After following this through and finding the fault go back to the lead-out wire (or first intersection). Then follow the next highest current reading. Repeat as necessary.
JVA Fault Finder Tip # 4.
Take the first fence reading at least 30cm from the energiser. Measuring the voltage of a fence at the energiser terminals may give misleading readings. Holding the JVA Fault Finder near an energiser will usually give a large current (Amps) reading due to the magnetic field from the energiser transformer. The JVA Fault Finder has a very sensitive magnetic field pickup which will be swamped by the large field from the energiser transformer. This effect can extend to about 30cm from the energiser.
JVA Fault Finder Tip # 5. Interpreting JVA Fault Finder readings on fences with two or more live wires.
If the fault is a long way away, the fault current (Amps) will usually be equally shared amongst parallel live wires. As you get closer to the fault then the wire with the fault on will carry the highest current. It is possible for some very surprising readings with multiple live wires. Following the fault arrows will always lead to the fault. Follow the wire with the highest current reading. If the JVA Fault Finder stops showing an arrow because the current is shared amongst many live wires, proceed to the end of that section of fence and take readings again where the live wires reunite.
JVA Fault Finder Tip # 6.
If you aren’t getting high enough voltage on a fence (and you know there are no faults) try adding more earth stakes. Or test the earth to see if any voltage is escaping. See upcoming Tips # 7 and # 8.
JVA Fault Finder Tip # 7.
When fault finding, check the earth wire for voltage. The earth wire should NOT be carrying voltage. Ignore the current reading (Amps) and fault direction arrows, these only work when testing a live wire. If the earth wire has voltage, it may be caused by induction rather than a short. Re-establishing a good ‘earth’ ensures the voltage is only on the live wire. See our next Tip for how to test the fence ‘earth’ stake with the JVA Fault Finder.
JVA Fault Finder Tip # 8. How to use the JVA Fault Finder to test the ‘earth’ on a fence.
Firstly, touch the JVA Fault finder (metal tip) to the top of the ‘earth’ stake. It should read less than 0.3kV (300 volts). Ignore the Amp reading and fault directions for this test. For an electric fence to be effective it is essential for the ‘earthing’ of the fence to be effective. The ‘earth’ stake should have little to no voltage.
JVA Fault Finder Tip # 9. Check insulated cables and underground cables.
Sometimes the power from the energiser doesn't even make it to the fence. The lead-out wire may be shorting out somewhere between the energiser and the fence connection. Underground wires and wires which run past or through metal shed walls commonly cause problems.
To test for this place the JVA Fault Finder over the live wire from the energiser (try to do this at least 30cm from the energiser itself). Note the current (amps) reading (the current can be read through an insulated cable, the voltage cannot). Next, take a reading where the lead-out wire connects to the fence. If the current reading is significantly (5 Amps) higher at the energiser there is a leak in between. The same technique may be used on underground cable by checking for a difference in current flowing into and out of the underground section.
JVA Fault Finder Tip #10. Short- out leads.
A SHORT-OUT lead is a useful tool for turning the electric fence OFF so that repairs can be undertaken while in the field. The short-out lead is a flexible wire with well-insulated alligator clips attached to both ends (like miniature jumper leads). It is best to connect the alligator clips to a good ‘earth’ first, then to the live wire. Be sure the short is between you and the energiser. You will need one short-out lead for each live wire. JVA can provide short-out leads or make your own or buy from Jaycar here they are sold in bulk as a Standard Jumper Test Lead Kit.
JVA Fault Finder Tip #11. If a gate is ‘live’ improve the ‘earth’ for the electric fence.
Is your gate “biting” you? And showing a voltage reading when measured with the Fault Finder? A “live” gate can be a bit of a shock (haha). It is usually the result of poor earthing, and a short on the live wires somewhere. You can reduce the problem by earthing the gate hinges to an earth wire or a new earth stake near the gate. See previous tips for how to check the earth and underground cables.
JVA Fault Finder Tip # 12. Fault Finding on BI-POLAR electric fences.
The JVA Fault Finder senses that it is being used on a BI-POLAR fence after it has touched both positive and negative wires. After this, the JVA Fault Finder will indicate which polarity (positive or negative) you are on. If the JVA Fault Finder placed on the positive live wire the + in the centre of the display will light. The JVA Fault Finder will get the direction of the fault correct even when you swap from positive to negative live wires as it knows which one you are on. The only time the JVA Fault Finder will become confused is if there is a short directly between the positive and negative live wires. In this case, the resulting voltage on both wires close to the fault may be zero or slightly positive or negative. The JVA Fault Finder will indicate that it is “guessing” the fault direction by flashing the arrow light.
JVA Fault Finder Tip # 13. JVA Fault Finder and its use with 'smart' energisers.
Smart energisers will typically increase the power when there is a heavy load on the fence. They may also reduce the output power when there is a dead short on the fence. The JVA Fault Finder will not be confused and will still work despite these power changes. You may, however, see fluctuating Voltage and Amps readings if the energiser ramps up and down.