How to Fault Find an Electric Fence
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An electric fence that isn't working properly can lead to escaped livestock, stress, and potential injury. Knowing how to systematically fault find your fence can save you time, money, and a lot of frustration. Here's a step-by-step guide to getting your fence back up to full voltage.
1. Check the Energiser First
Start at the source. Make sure the energiser is switched on and receiving power. For mains units, check the fuse and that the plug is securely connected. For battery units, check the battery charge — a flat battery is one of the most common causes of fence failure. For solar units, ensure the panel is clean and facing the sun.
Check the energiser's fault indicator. Most modern energisers have a visual or audible fault warning that activates when there's a short circuit or grounding issue.
2. Test the Voltage at the Energiser
Use a fence voltmeter to check the output voltage directly at the energiser terminal. You should be reading at least 5,000 volts for a deterrent effect. If the voltage is low or zero at the energiser, the problem is with the energiser itself — check the settings, replace the battery, or contact the manufacturer.
3. Test the Voltage at the Fence Line
Walk the fence line and test the voltage at intervals using your fence voltmeter. Voltage will naturally drop with distance, but a significant drop at a specific point indicates a problem nearby. Common causes include:
- Vegetation touching the wire — the most common cause of voltage loss; trim any grass, brambles, or branches contacting the fence
- Damaged insulators — cracked or broken insulators can allow the wire to contact the fence post, grounding the fence
- Broken or loose wire — check for snapped strands, loose clips, or wires that have worked free from insulators
- Damaged fence posts — wooden posts that have rotted or metal posts that have bent can cause the wire to ground out
4. Check Your Grounding System
A poor grounding system is one of the most overlooked causes of fence failure. The energiser needs a good earth to complete the circuit. Check that:
- Grounding rods are fully driven into the ground and not corroded
- The ground wire is securely connected to both the energiser and the grounding rods
- The soil around the grounding rods is moist — dry soil significantly reduces grounding effectiveness
In dry conditions, consider watering the grounding area or adding additional grounding rods.
5. Inspect Gates and Gate Lines
Gates are a weak point on any fence. Check that:
- Gate line connectors are clean and making good contact
- The gate line wire isn't dragging on the ground
- Gate insulators are intact and the wire isn't contacting the gate frame
6. Check for Animal Damage
Livestock can damage fences by rubbing against them, chewing wires, or pushing through weak points. Look for:
- Chewed or frayed wire
- Bent or broken insulators
- Posts that have been pushed over or loosened
7. Use a Fence Tester or Fault Finder
For longer fences, a dedicated fence fault finder can help pinpoint the exact location of a short circuit or break. These devices send a signal along the fence line and detect where the signal is interrupted or grounded.
8. Regular Maintenance Prevents Faults
The best fault finding is prevention. A regular maintenance routine will keep your fence in good condition and reduce the likelihood of failures:
- Walk the fence line monthly and trim vegetation
- Check insulators and wire connections seasonally
- Test voltage at the fence line regularly, especially after storms or heavy grazing periods
- Keep a record of any repairs made and where
Summary Checklist
- Check energiser power source and fault indicator
- Test voltage at the energiser terminal
- Walk the fence line and test voltage at intervals
- Trim vegetation contacting the wire
- Inspect insulators, wire, and fence posts
- Check grounding system and connections
- Inspect gates and gate lines
- Look for animal damage
- Use a fault finder for longer fences
If you need help finding the right energiser or fencing supplies, browse our full range of Electric Fencing, Energisers & Fence Supplies or contact our team for expert advice.