Electric Fence Fault-Finding — Sandton & Northern Suburbs
Electric Fence Not Shocking?
Electric fence not shocking even though it shows voltage? It is almost always the earth. We test and fix earthing, output and energiser faults same-day across Johannesburg.
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Diagnosed properly, fixed once
Electric Fence Not Shocking? The Cause Is Usually the Earth
An electric fence that no longer gives a real shock is a fence that has quietly stopped deterring anyone — even if the energiser light is green and your tester shows a healthy reading. It is one of the most misunderstood faults in the trade, because the fence looks fine while doing nothing. This guide explains why a fence can read thousands of volts and still barely sting, what actually causes it, and how we restore the bite. Paskwa Gate Repairs fixes this across Sandton, the northern suburbs and greater Johannesburg, usually the same day.
The key idea is that voltage and shock are not the same thing. A shock is current flowing through whatever touches the live wire, down to earth, and back to the energiser through the earth wires and earth stakes. If that return path through the ground is poor, the pulse has plenty of voltage but nowhere to flow — so it stings weakly or not at all. That is why the earth system, not the energiser, is the usual culprit.
Know your system
How an Electric Fence Works — in Plain Terms
Before getting to a fence that won't shock, it helps to understand what the system is doing, because almost every fault makes sense once you do. An electric fence has three jobs rolled into one: it deters (a visible, shocking barrier), it detects (an alarm when the perimeter is breached), and it delays (a physical obstacle that buys time). The component that makes all three possible is the energiser.
The energiser takes mains, battery or solar power and converts it into a short, high-voltage pulse — roughly one a second — that it sends along the live wires at around 7,000 to 9,000 volts on a healthy system. The wires are held off the earthed brackets and posts by insulators, so the pulse stays on the line. When anything bridges a live wire and the ground — a person, an animal, a branch, a cut tool — current flows through it to earth and back to the energiser through the earth wires and earth stakes. That flow is the shock, and it is also what the energiser measures: when the returning voltage drops, it knows the line has been loaded or breached and it raises the alarm.
So a working fence needs four things in good order: a healthy energiser making a strong pulse, intact insulators keeping the pulse on the live wires, a good earth system to complete the circuit, and a sound, correctly-tensioned line of wire. When one of those drifts out of condition, you get the symptoms people call us about — no shock, constant alarms, beeping, or a dead fence. Knowing which of the four has failed is the whole of the diagnosis.
This is also why electric fence faults resist guesswork. The same symptom can have several different causes across those four systems — a weak shock might be a bad earth, a partial short or a tired energiser — and the only reliable way to tell them apart is to measure: open-circuit output at the energiser, earth-return voltage, and readings along the line. A technician who tests rather than swaps parts gets to the real cause faster and, in the end, cheaper for you.
Voltage vs shock
Why Your Tester Can Read High and the Fence Still Won't Bite
When you put a fence tester on the live wire, you are usually measuring open-circuit voltage — the potential with nothing completing the circuit. That can read a healthy 7,000 to 9,000 volts while the fence is useless, because the moment a person or an intruder touches it, the current has to complete its loop back through the soil and the earth wires. If the earth is weak, almost no current flows, and there is no meaningful shock.
This is why 'it shows voltage so it must be fine' is the most expensive assumption in electric fencing. The honest test is not the headline voltage; it is the earth-return reading and the shock under a real load — and that is what we measure on site.
The main cause
The Number-One Cause: a Poor Earth System
Most 'not shocking' fences in Johannesburg have an inadequate or degraded earth. The system relies on galvanised earth stakes driven into the ground to complete the circuit, and several things undermine them: too few stakes for the length of fence, stakes driven too shallow, corrosion on the stakes or the earth lead over years, and — the big seasonal one — the dry Highveld winter baking the soil until it barely conducts. A fence that shocked perfectly in February can go limp by July purely because the ground has dried out.
We measure earth-return voltage to confirm it. As a rule of thumb, a reading much above around 300 volts on the earth side means too much of the pulse is being lost in a poor earth rather than completing cleanly. The fix is to add or re-drive galvanised stakes deeper into moister ground, clean or replace corroded earth leads, and bond the earth system properly so the circuit completes and the bite returns.
Other causes
The Other Reasons a Fence Stops Shocking
A partial short bleeding the pulse away
Vegetation, a cracked insulator or a sagging wire leaking to earth steals current before it reaches where you are testing, weakening the shock along the line. Often this also trips the alarm — but not always, if the leak is marginal.
An energiser too small for the fence
If the fence has been extended, or a powerful unit replaced with a weaker one, the energiser may simply lack the joules to drive the full length of wire to a deterring shock. We match the joule rating to the line.
Output set too low
Some energisers have adjustable output or 'day/night' settings. A unit dialled down, or left on a low setting, gives a feeble shock. We check and set it correctly.
A weak or failing energiser output stage
A unit that has taken surge damage can still light up and read some voltage while its output stage is degraded, producing a soft pulse. An open-circuit output test against the unit's rating reveals this.
How we test
How We Diagnose a Fence That Won't Shock
We start at the energiser with an open-circuit output reading to confirm the unit itself is making a healthy pulse against its rated joules. Then we measure earth-return voltage to see how much is being lost in the ground — the single most revealing test for this fault. Finally we walk the line taking readings at intervals; a steady drop that recovers past a point isolates a leak, while a uniformly weak shock with a high earth-return reading points squarely at the earth system.
It is a logical sequence that separates the three real possibilities — bad earth, a leak, or a weak energiser — instead of guessing. Most of the time it ends at the earth, and most of the time the fix is straightforward.
The physics, simply
How the Shock Is Actually Delivered
It helps to picture what happens in the instant someone touches the fence. The energiser has charged the live wires to several thousand volts. When a person bridges a live wire and the ground, they momentarily become part of the circuit: current flows from the live wire, through them, into the soil, across to the earth stakes and earth wires, and back to the energiser. The sensation we call a shock is that brief surge of current passing through the body.
The voltage is what makes the current want to flow; the earth is what lets it actually flow. If either is missing, there is no meaningful shock. A fence can sit at 8,000 volts all day, but if the return path through the ground is poor, almost no current moves when someone touches it — high voltage, negligible current, no deterrent. This is also why the energiser's joule rating matters: joules describe how much energy is in each pulse, and a unit with too few joules for a long fence simply cannot push a convincing shock to the far end even with a perfect earth.
So a complete, healthy shock needs three things working together: enough voltage, enough energy (joules) for the length of fence, and a good earth to complete the circuit. When a fence stops shocking, one of those three has failed — and far more often than not, it is the earth.
The seasonal trap
Why Highveld Winters Quietly Kill the Shock
Johannesburg's climate sets a trap for electric fences. Through the summer rains the soil is damp and conducts beautifully, so the earth circuit completes easily and the fence shocks hard. Then the dry winter arrives, months pass without rain, and the ground bakes dry. Dry soil is a poor conductor, so the very same earth system that worked perfectly in February can no longer complete the circuit by July.
The fence has not changed and the energiser is fine — the earth has simply lost its grip on the ground. This is one of the most common 'my fence suddenly stopped shocking' calls we get, and it peaks every winter. The fix is to drive earth stakes deeper to reach the moisture that remains below the dry surface layer, add stakes if there are too few, and clean up corroded earth connections. Done properly, the bite returns and holds through the seasons.
This is serious
Why a Non-Shocking Fence Is a Security and Legal Risk
A fence that does not shock is worse than no fence, because it gives a false sense of security. It looks like a working deterrent, the light is green, and yet an intruder who tests it feels nothing and climbs over unbothered. The whole point of the perimeter — to deter and delay — has quietly evaporated while everyone assumed it was fine.
There is a compliance dimension too. A properly functioning fence, including adequate earthing and output, is part of what a compliance inspection assesses. A fence that underperforms is unlikely to satisfy a thorough Electric Fence System Certificate of Compliance assessment, which matters if you are selling the property or have altered the system — and a non-compliant fence can complicate insurance. Restoring real shock performance is therefore not just about security; it keeps you on the right side of compliance and cover.
Keep the bite
Keeping the Shock Strong All Year Round
A little maintenance keeps a fence shocking reliably through the seasons:
- Have the earth-return checked at least once a year, ideally heading into winter when the soil dries out and earths fade.
- Keep vegetation trimmed off the line — every leaking branch steals current that should be going into the shock.
- Replace cracked insulators promptly; each one is a small leak that adds up to a soft fence.
- Match the energiser to the fence — if you have extended the perimeter, the original unit may no longer have the joules to drive it.
- Confirm the output is on its correct (full / night) setting rather than a reduced day setting.
- Test the actual shock and earth-return, not just the headline voltage on a tester, which can read healthy while the fence does nothing.
The local factor
Load Shedding, Surges and Your Electric Fence
No single factor damages electric fences in Johannesburg more than the power situation, and it is worth understanding because it shapes both why fences fail and how to protect them. During an outage, a mains energiser switches to its backup battery and the fence keeps pulsing — exactly as designed. The damage comes not during the outage but at the moment power is restored, when the grid often returns with a voltage spike. That surge travels into the energiser's power-supply stage and, on a board with no surge protection, punches straight through sensitive components.
This is why so many energiser failures appear in the hours after the lights come back on, and why a unit can survive many outages and then die on one. There is a slower, parallel cost too: every deep discharge during a long outage ages the backup battery faster than its rated two-to-three-year life, so heavy load shedding tends to wear out the battery and stress the board on overlapping timelines, producing dead fences, beeping and false alarms.
The defences are inexpensive relative to the damage they prevent: a surge protector on the supply, an intact and correctly-earthed lightning diverter, and, for properties that keep losing units, conversion to a solar energiser that runs off its own panel and battery and never sees the mains spike at all. We fit surge protection as a matter of course on board replacements, because protecting the repair is part of doing it properly.
Before you call
Safe Checks You Can Do First
None of these involve touching the fence wires — never test an electric fence by hand. They are quick checks that sometimes save a call-out and always help us help you faster over the phone.
- Never test the fence by touching it. Use a proper fence tester, and if you do not have one, leave it to us — assuming a fence is 'not really shocking' and grabbing it is exactly how people get hurt.
- Check the energiser is on its full / night output setting rather than a low or day setting, if your model has one.
- Look for obvious vegetation or a visibly sagging wire bleeding the line to earth, and note it for us.
- Note whether the weak shock is everywhere or only at the far end — it tells us whether to suspect the earth or a break.
Right now
Is This an Emergency? What to Do Before We Arrive
Not every electric fence fault is an emergency, and knowing the difference helps you act sensibly. If you have found a cut or pulled-down wire, treat it as a possible intrusion attempt: alert your armed-response company first, keep people and pets away from any loose, possibly-live strand, and call us to repair and re-test — including confirming the alarm actually reached your monitoring. If the fence is simply dead, weak, beeping or nuisance-alarming with no sign of tampering, it is not a 999 situation, but it does mean your perimeter is compromised, so it is worth sorting quickly rather than living with it.
Either way, do not try to investigate the high-voltage side yourself — no touching the wires, no opening the energiser. The safe, useful things you can do are all observation: note the symptom precisely, when it started, and whether it follows a pattern (after a power cut, only in rain, only at night). If you can do so safely from the ground, a quick photo of the energiser's display and of anything obviously wrong on the line is genuinely helpful.
Then call or WhatsApp us for a free telephonic diagnosis. With the brand of your energiser, its status light or screen message, and the symptom pattern, we can usually tell you the likely cause and an honest price range before we travel, and bring the right parts on the vehicle. Close to our Broadacres base that often means a same-day, single-visit fix; further out we will give you an honest planned time. The two minutes you spend describing it accurately is what turns a repair into a one-visit job.
A word on safety
Why Electric Fence Work Is Not a DIY Job
An electric fence is a high-voltage system. A healthy energiser delivers a pulse of several thousand volts, and while the design is intended to deter rather than injure a healthy person, the high-voltage side is not something to probe, open or repair without the right knowledge and equipment. The safe checks we suggest are deliberately limited to things you can do without touching the wires or opening the unit — looking, listening and noting — precisely because everything beyond that belongs with a technician.
There is a second reason beyond personal safety: a fence worked on incorrectly can be left non-compliant, under-performing, or falsely reassuring. A botched earth, a wrong-rated energiser, a join that becomes a short, or an alarm output left disconnected can all leave a fence that looks fine and protects nothing. We carry the test equipment to diagnose properly, the stock to repair in one visit, and the knowledge to leave the system both safe and genuinely working — backed by a six-month guarantee, which a DIY attempt cannot give you.
Brand-by-Brand Guide
Electric Fence Brands We Work With
South African electric fences are dominated by a handful of brands, and knowing the quirks of each is half the job of a fast, correct repair. We carry the common units and spares on the vehicle, so most faults are diagnosed and fixed in a single visit across Johannesburg.

Nemtek — Wizord, Merlin, Stealth & Druid Electric Fence
Nemtek is the most common security energiser on Johannesburg homes, complexes and estates, and the brand we replace most often. The Druid LCD range uses Nemtek's Adaptive Power Technology (APT), which senses how much power the fence can take before it arcs — maximising voltage and cutting false alarms. We repair board-level faults where economical and stock the popular units for same-day replacement.

Stafix Econoflex electric fence energisers
Stafix is reliable, SANS-approved and widely installed across Gauteng — and because Stafix and Nemtek share most installation hardware (brackets, wire, bobbins), a Stafix board swap rarely means re-doing the fence. We follow the Stafix six-step fault-finding sequence: check the power supply and battery, test the energiser open-circuit, then the lightning diverter, the lead-out, the earth and finally the fence line.

Gallagher B10, B30, and B80 electric fence energisers
Gallagher energisers are built for long fence lines and heavy vegetation load — the right choice for Johannesburg's larger plots, smallholdings, estate boundaries and game fencing that can run to several kilometres of wire. The job here is matching the joule rating to the line so the fence holds voltage end to end; as a rule of thumb, one joule drives roughly 10 km of clean wire, far less where vegetation competes.

DSC and Risco electric fence alarm systems
The shock deters; the alarm protects. The energiser's alarm output is what signals your armed-response company when a wire is cut or shorted — and on far too many Johannesburg fences it was never wired in. We integrate the output into DSC and Risco panels, set the gate-bypass so opening your gate doesn't false-alarm every time, and confirm the trigger end to end.

Solar electric fence energisers
Solar electric fence energisers provide uninterrupted perimeter protection during load-shedding and power outages. These systems are ideal for off-grid properties, farms, estates, and remote security installations. Solar energisers combine rechargeable battery backup, solar charging technology, and efficient power management for continuous operation.
How we work
Our Process, Pricing & Guarantee
Every job starts with a free telephonic diagnosis. Tell us the symptom — the pattern of the alarm, the status light, whether the fence is dead or weak — and we will give you the likely cause and an honest price range before anyone drives out, so there are no surprises. The call-out is from R450 and is waived when you proceed with the repair.
On site, we diagnose with proper test equipment rather than swapping parts and hoping: open-circuit output at the energiser, earth-return voltage, and directional fault-finding along the line. We repair before we replace, and where a replacement is genuinely the better value we say so and explain why on the numbers, never on pressure. Because we carry the common stock on the vehicle, most faults are fixed in a single visit.
Then we re-test the whole system — output, earth and the alarm — so you leave with a fence that shocks properly and warns you if it is breached, not just one that has had its immediate symptom silenced. Every repair carries a six-month guarantee, and you deal directly with our team throughout: no call centres, no commission-driven upselling.
Myth-busting
Common Misconceptions About Electric Fence Faults
“It shows voltage, so it must be working”
A tester reading high voltage only proves the energiser is making a pulse — not that the fence shocks or alarms correctly. A fence can read 8,000 volts and give almost no shock if the earth is poor, because the shock depends on current completing the circuit through the ground. The meaningful tests are earth-return and the shock under load.
“The alarm is faulty because it keeps going off”
Far more often the alarm is working perfectly and correctly reporting a real fault on the line — vegetation, a cracked insulator, a sagging or cut wire. The alarm is the messenger; silencing it leaves the actual problem in place. The fix is to find what is tripping it.
“A new battery will fix a fence that keeps dying”
Sometimes — but if a fresh battery fails within months, the real fault is the charging circuit or a surge-damaged board mismanaging it. Replacing batteries on repeat without diagnosing the charger just throws money away.
“Any electrician can issue my fence COC”
No. An electric fence Certificate of Compliance may only be issued by an installer registered with the Department of Employment and Labour for that purpose — it is separate from the ordinary electrical COC and a separate registration.
Questions answered
Electric Fence Beeping Problem — FAQs
My fence shows voltage on the tester but doesn't shock — why?
Because voltage and shock are different things. The tester reads open-circuit voltage, but the shock depends on current completing the circuit through the earth. If the earth system is weak — too few stakes, dry soil, corrosion — the pulse has voltage but cannot flow, so there is little or no bite. We measure earth-return voltage to confirm and correct the earth.
Can dry weather really stop my fence shocking?
Yes. The Highveld's dry winter bakes the soil until it conducts poorly, so a fence that shocked well in summer can go weak by mid-winter purely because the earth has dried out. The fix is to drive earth stakes deeper into moister ground and improve the earth bonding.
How many earth stakes should my fence have?
It depends on the length and the energiser, but a common guideline is an earth point roughly every 30 metres of fence, driven properly into the ground. Too few or too shallow is one of the most common reasons a fence stops shocking. We assess and add what your system needs.
Is a fence that doesn't shock still compliant / will it pass a COC?
A fence that does not perform — including poor earthing and inadequate output — is unlikely to pass a proper compliance inspection, and it certainly is not protecting you. We restore correct voltage and earthing, and can advise on certification if you are selling or have altered the system.
Could the energiser be the problem rather than the earth?
It can be — a surge-damaged unit may light up and read some voltage while its output stage is weak. We test open-circuit output against the unit's rated joules to separate a weak energiser from a poor earth, so you only pay to fix what is actually wrong.
Is a constant alarm a sign someone is trying to break in?
It can be — a cut or pulled-down wire will alarm, and that is the system doing its job. If you find damaged or missing strands, treat it as a possible intrusion attempt, alert your armed response, and call us to repair and re-test, including confirming the alarm output actually signals your monitoring.
How Many Strands Does My Electric Fence Need?
SANS 10222-3 specifies a minimum of 5 live strands for a compliant installation. Most Johannesburg residential installations use 6–8 strands for better coverage. The strands must be properly spaced, tensioned and earthed, and warning signs must be displayed at regular intervals. All our installations comply with SANS 10222-3 and include a COC certificate.call 061 402 6299 for emergency repair.
Is a weak shock dangerous to ignore?
It defeats the purpose of the fence — an intruder feels little and climbs over — so from a security standpoint it should not be ignored. It can also be a symptom of a developing earth or energiser problem that will only worsen. Restoring proper shock is both a security and a system-health fix.
How do you find the short without checking the whole fence?
A directional fault-finder reads the pulse and points toward the leak, and zone isolation tells us which section is at fault. We locate the short to within a metre or two rather than walking the whole perimeter blind, which keeps the time — and your bill — down.
How Long Does Electric Fence Installation Take?
A standard residential electric fence installation in Johannesburg takes 1–3 days depending on perimeter length and complexity. We usually start within 48–72 hours of the free site assessment. The COC certificate is issued on the day of completion.
Why does my fence have power but no shock when touched?
A fence that reads voltage but doesn't deliver a proper shock is nearly always an earthing problem — the most common cause of weak output. A good earth needs at least three galvanised stakes driven into moist ground. We test earth resistance and correct it; sometimes the energiser is also undersized for the line length and needs upsizing.
Why does only part of my fence shock?
That points to a partial short or a break partway along the line — vegetation or a cracked insulator bleeding the pulse, or a damaged strand or lead-out so the far end is starved. We walk the line taking readings to find where the shock drops off and address that section.
Can you repair my brand of energiser?
Yes — we work on Nemtek (Wizord, Merlin, Stealth, Druid, Agri), Stafix, JVA, Gallagher and others, plus solar energisers and DSC/Risco fence-alarm integration. Where a board is beyond economical repair, we replace it with a like-for-like unit so your existing brackets, wire and keypad stay in place.
How much does it cost to get the shock back?
An earth-system repair is typically R650–R1,400, which fixes the majority of cases. If the energiser is undersized or weak, repair or replacement ranges from R600 to R6,500 depending on the model. Diagnosis is from R450 and waived on repair.
Have a different Question?
Get In Touch
Get Your Fence Shocking Again — Book Today
Speak directly to our dispatch team — no call centres. We test the earth and the output properly and restore a fence that actually deters, not just one that reads a number.
- 061 402 6299 — Call or WhatsApp
- info@paskwagaterepairs.co.za
- 7 Poplar Avenue, Broadacres, Sandton, 2021
- Mon–Fri: 07:00–18:00 | Sat - Sun: 07:00–14:00
- 24/7 Emergency Line available
Book a Free Quote
Who we help
Homes, Complexes, Estates & Commercial Sites
Electric fence faults do not respect property type, and neither do we. On freestanding family homes the typical work is vegetation shorts, cracked insulators, surge-damaged energisers and tired batteries, fixed quickly and guaranteed — the bulk of everyday residential call-outs sit here.
On townhouse complexes and estates the systems are usually multi-zone, so a fault can be isolated to one section without dropping the whole perimeter, and the Certificate of Compliance for common-property fencing is generally the body corporate's or homeowners' association's responsibility — so we coordinate with the managing agent and report properly. A maintenance contract often makes sense at this scale.
On commercial and industrial premises, detection matters as much as deterrence: the priority is that the fence genuinely alarms to monitoring or armed response when it is breached, and that the work is documented for insurers. We verify the alarm output, integrate with alarm panels where needed, and service to scheduled windows so cover is never down during operating hours. Whatever the property, the same honesty, testing and guarantee apply.
Compliance
A Word on Your Certificate of Compliance
If you are selling your property, or you have installed, altered or replaced the energiser, you may need an Electric Fence System Certificate of Compliance. It is a separate certificate from the ordinary electrical COC, it is required for property transfers and for new or altered installations, and only an installer registered with the Department of Employment and Labour may issue one — confirming the system meets SANS 10222-3 and SANS/IEC 60335-2-76.
Routine minor repairs such as replacing wires, insulators or bobbins do not trigger a new certificate, but replacing the energiser does, because it materially changes the system. We will tell you honestly which applies to your situation, and can arrange certification through a registered installer. This is general guidance, not legal advice — for a property sale, confirm the current requirements with your conveyancing attorney.
Where We Work
Areas We Cover
We cover Sandton, the northern suburbs and the greater Johannesburg area from our Broadacres base, with honest travel times the further out you are. Suburbs close to base get same-day and often within-the-hour attention; further afield, across the East Rand, West Rand and out toward Pretoria, we work on a planned same-day or by-appointment basis and arrive fully stocked so the fault is still fixed in one trip.
- Alberton
- Douglasdale
- inanda
- Morningside
- Saxonwold
- Bedfordview
- East Rand
- Johannesburg
- Randburg
- Benoni
- Edenvale
- Kyalami
- Roodepoort
- Bryanston
- Fourways
- Melrose Arch
- Rosebank
- Centurion
- Hyde Park
- Midrand
- Sandton
Not listed? We cover all of Gauteng — call 061 402 6299 to confirm availability for your area.
