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The Six Basic Fault Finding Procedures
In order to determine the reason for lack of voltage on a fence line the following six steps should be followed.
Step 1: Start at the Electronic Components: (Power Supply, Battery, Energizer)
A) Check the energizer rating:
Check that the energizer installed has a sufficient Joule rating to cope with the fence line it has been connected to. Has the fence line been recently lengthened to beyond the energizers capabilities? If the energizer is sufficient continue to point B.
B) Check the 220V A/C Supply:
This is a fairly obvious step but often overlooked. Check that the system is plugged in and that the A/C power is switched on.
C) Check the 12V Battery Supply:
D) Check the battery Charger:
Disconnect the power supply from the battery and using your multi meter check that the battery has more than 12V across its terminals. (12.8 – 13.2 is ideal). If the battery voltage is low continue to point D, if it is OK continue to point E.
The voltage on the battery will be low if a cell has blown or if the power supply is not charging. The Hawkins Fence Pro Battery Chargers are polarity protected and need to be tested while connected to a battery.
1) Using the multi meter test the voltage on the battery before and after connecting the charger. If the latter produces a higher voltage the charger is working. This will mean that the battery is not holding charge and will need to be replaced. If the charger is not charging continue to step 2.
2) The Hawkins power supply has HV protection from both the 12V and 220V inputs. Using the multi meter check that the fuses are working. If a fuse is found to be blown replace it with a equivalent fuse. After replacing the fuses repeat Step 1, if this does not fix the charger it will need to be sent in to your nearest Stafix agent.
E) Check the Energizer
Disconnect the energizer from the HT leads to the fence and using a Stafix Digital Volt meter (DVM) or Stafix Fence Compass test the open circuit voltage of the energiser. A reading of 7 KV or more should be read on an open circuit. If the voltage is sufficient reconnect the HT leads. If adequate voltage is not achieved, the energizer will need to be sent to your nearest Stafix agent for repairs.
Step 2: Test the Lightening Diverter (LDV) System
The LDV is designed so that if very high voltages caused by a lightening strike were to come across it the voltage will be diverted through the L.D.V. to ground protecting the energizer system. The high voltage Spikes can cause the diverter to “pop” as the carbon plates inside it fuse together. This can cause a dead short to earth. To test the LDV do the following.
1. Using a Stafix DVM or Fence Compass take a reading on the HV side of the diverter. A high voltage should be read.
2. Repeat the test on the earth side of the LDV. A zero reading should be read. If any voltage is detected the LDV will need to be replaced.
Step 3: Test the High Voltage Lead Out System
Breaks and cuts in the HT cable between the energizer and the fence, under gates and between the fence and the monitor will cause drops in voltage. To test the lead out cable the following steps needs to be followed:
1) Switch the energizer off.
2) Disconnect the HV undergate lead out where it is connected to the fence.
3) Switch the energizer on.
4) Test the voltage on the HT lead out. If the voltage is the same, or within a few hundred volts of the energizer test bench voltage, the lead out is OK.
5) On a monitored electric fence the HT return will need to be tested. To test the return HT cable, disconnect the return and the HV at the fence and bridge them together. This will complete the energiser circuit while excluding the fence from the system.
Take a voltage reading back at the monitor. If the voltage is the same or within a few hundred volts of the energizer test bench voltage, the lead out is OK.
If at anytime during steps 3.2 and 3.3 the voltage has dropped significantly, the lead out cable would have been shown to be damaged and will need to be replaced. If the cables are shown to be fault free, reconnect them to the fence and begin with step four.
Step 4: Test the Earthing System
TESTING YOUR EARTH
If your fence is not giving the shock you expect, it is most likely to be your earth system. The earth is half the effective circuit in an electric fence system.
- The main causes of an ineffective earth are:
- Insufficient earth rods.
- Badly connected wires, or wires of different metal types joined together.
- Poor connection to the earth rods.
- Earth rods too close together.
- Earth rods not long enough.
Depth is important to good earthing as it ensures that part of the earth rod is always in damp soil.
TESTING YOUR GROUND EARTH RETURN
1. Create a dead short by placing enough steel stakes against the fence line to reduce the voltage to 1000 volts or less. These stakes should be at least 100m (330ft) from the earth system.
2. Connect one clip from your Stafix Digital Voltmeter to the last earth rod. Connect the other clip to a small stake placed in the ground at least 1m (3ft) .5 from any other earth rods.
3. The reading on the Voltmeter should be 0.3 kV or less. If it is greater than this, the earth system is Inadequate and more earth rods will need to be added.
TESTING YOUR FENCE EARTH RETURN
1. Do this test as close as possible to the end of the fence & line.
2. Place a steel rod or stake at least 0.3m 1 ft Into the ground, preferably into damp soil.
3. Measure the voltage between the earth wires and live wires on the fence and then between the steel rod and the live wires.
4. The voltage between the earth stake and live wire should not be more than 0.3kV greater than the voltage between the live and earth wire.
5. If the difference is greater than 0.3 kV then check the earth return wire for loose connections. Also remember to check the live wires. If the live wires are alright you will need to add more earth rods along the fence line and attach these to the earth wires.
Remember, surveys have shown that over 80% of electric fencing systems suffer from inadequate earthing. So, spend a little extra time on this important aspect of your electric fence and enjoy many years of trouble free fencing.
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Step 5: Check the Fence System
There are a number of reasons for reduced voltage on the fence line. The Stafix Digital Volt Meter and Stafix fence Compass are excellent tools to help guide you to the vicinity of the fault, but the final fault will need to be found using your eyes.
The following slide show identifies some possible faults you will find on an electric fence:
On a large fence system the value of Stafix Cut Out Switches becomes obvious, as the fault can be isolated to a specific sector of fencing.
By a process of elimination, beginning at the first cut out switch (Closest to the energiser lead out) the sector containing the fault can be identified. When the area of fence containing the fault is switched off, the voltage on the remainder of the fence will rise.
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