Electric fence not working? The common causes, step by step
A beeping energizer, an alarm that will not stop, or a fence that has gone silent. Most faults come from a short list of causes. This guide helps you understand what is going on and describe it to an installer. It does not replace a registered installer's test.
Safety first
Do not touch the strands, and do not try to lift, join or move a wire while the fence is on. If you need to do anything near the fence, switch it off at the energizer first and keep children and pets away. Leave electrical work, opening the energizer and changing the wiring to a registered Electric Fence System Installer. Looking is fine; touching is not.
Step 1: what is the energizer telling you?
Start indoors. Most energizers have lights, a display or a beep pattern, and the manual explains what they mean. Note exactly what you see and hear: which lights are on, any error code, whether it beeps all the time or only now and then, and whether the alarm panel shows a zone. Take a photo. That information is often enough for an installer to know where to start.
- No lights, no sound. Likely a power problem, a tripped plug or a failed energizer. Check whether the plug point has power.
- Battery warning, or the fence dies in power cuts. Likely a flat, old or non-charging battery.
- Low voltage or line fault. Something is draining the fence: vegetation, a short, a broken insulator or a poor earth.
- Constant or repeated alarms. Often a broken strand, a short, or an intermittent fault that comes and goes with wind or rain.
Step 2: walk the fence and look
With the fence switched off at the energizer, walk the boundary and look without touching. You are looking for anything obvious. Most faults are found at the same few places: gates, corners, the back of the garden where nobody goes, and anywhere plants grow along the wall.
- Branches, creepers, hedges or long grass touching any strand, especially the lowest ones.
- A strand that is broken, lying on the wall, sagging or touching another strand.
- Cracked, missing or burnt-looking insulators.
- Brackets that have rusted, bent or pulled loose from the wall.
- Damage from a fallen branch, a builder, a ladder or a neighbour's work.
- Debris such as wire, wet cloth or a plastic bag caught on the fence.
Step 3: think about the earth
An electric fence works by completing a circuit: the pulse goes out along the live strands and returns through the earth system. If the earth is weak, the fence may read low, give false alarms or behave differently in wet and dry weather. Earth spikes can corrode, connections can come loose, and dry Highveld winters can change how the ground behaves. An earth fault is not something you can see easily; it needs an installer's test. Our guide to electric fence voltage and earthing explains how it works.
Step 4: consider the energizer and battery
If the fence looks clear and the earth is sound, the energizer or its battery may be the problem. Energizers can fail with age or take a surge in a thunderstorm. Batteries wear out, especially after many long power cuts. An installer usually disconnects the fence and tests the energizer on its own: if it works off the fence, the fault is on the fence; if not, the fault is in the unit. See energizer and battery replacement.
Faults that come and go
Intermittent faults are the most frustrating. A fence that alarms on windy nights may have a strand that touches the wall when it sways, or a branch that brushes it in the wind. A fence that alarms after rain may have a cracked insulator that only leaks when wet, or an earth that changes with moisture. Keep a short diary of when the alarms happen and what the weather was doing. It saves the installer time and you money.
When to call an installer
Call a registered installer if a strand is broken or down, if you cannot find an obvious cause, if the energizer shows a fault you do not understand, or if the fence stopped after a storm. Describe what you saw in steps 1 and 2. A repaired electric fence must comply with SANS 10222-3, and the user or lessor must hold a valid Electric Fence System Certificate of Compliance (source: ECA(SA)). This is general information, not legal advice.
See electric fence repairs, or local pages such as repairs in Montana and repairs in Wierda Park. If the same fault keeps coming back, regular maintenance may be cheaper in the long run.
Frequently asked questions
Why does my electric fence beep all the time?
Usually because the energizer has detected a fault: something touching the strands, a broken wire, a weak earth or a battery problem. Check the energizer's display or lights first.
Can I clear branches off the fence myself?
Only after switching the fence off at the energizer, and without touching the strands. If in doubt, ask an installer.
Why does my fence alarm only when it rains?
Common causes are a cracked insulator that leaks when wet, or an earth system that changes with moisture. An installer can test for both.
Why does my fence stop working when the power goes?
The backup battery is probably flat, old or not charging. Ask an installer to test and, if needed, replace it.