Electric fence not working: what to check

Everything on this page is done by looking, and by using the keypad. Never touch the fence wires to test them, and never open the energiser: it holds high voltages inside, and both are jobs for us. If something is lying across the fence, leave it until the fence is switched off, and if you're not certain it's off, leave it for us.

• The energiser is dead: no display, no lights, no ticking. See power.
• The energiser is on, but the fence is off or on low power. See switched off.
• The fence is on, but weak, or alarms for no clear reason. See a weak fence.
• It went wrong after a power cut or in the rain. See after a power cut and rain.
• The alarm keeps going off. That has its own guide: electric fence alarm keeps going off.

An energiser runs from the mains, with a battery to carry it through outages. If the display is blank and nothing lights:

• Check the plug point and its switch, and whether the rest of the property has power.
• Read the signals if there are any. Nemtek's Druid LCD shows when the mains has failed, and whether the battery is good, low or flat. A JVA Z-series energiser flashes its status light twice for a mains failure and three times for a low or failing battery.
• Give the battery time after a long outage before judging it.

A dead energiser with the mains on is a fault inside it, often after a storm or a surge, and that's a bench repair or a replacement.

A fence that seems dead may simply be off. On a Nemtek Druid LCD, a 0 means the fence is off, and lo means it's set to low power. JVA's Z-series energisers also have a low power mode, made for detection with public safety in daytime, so a fence that feels weaker by day may be working exactly as set.

Check the keypad: arm the fence with your code if it's off, and switch it to full power if that's how it should run. If it won't arm, or switches itself off again, call us.

Nemtek's Druid LCD gives the fence a condition score from 0 to 9, and higher is better. It also shows ! when the fence voltage drops below the check level and x when it falls below the alarm level. Both levels are set by the installer.

What pulls a fence down is almost always the fence itself, not the energiser. Nemtek's own list of what keeps the score high is practical:

• Cutting back plants that grow into or onto the fence.
• Clearing slugs, snails, spiders and insects off the insulators.
• Replacing failed insulators, the cracked or burnt ones that leak current into the wall.

That's fence maintenance, done with the fence switched off, and it's what we do on a service. What you can do is look along the fence, without touching it, and tell us where plants, broken wires or damaged insulators are.

If the fence alarms or weakens every time it rains, the insulators are the usual suspects. Nemtek names wet insulators after a rain storm, along with poor or damaged ones, as a reason a fence can't hold a high voltage. Dirt and insects on an insulator are harmless when dry and conduct when wet.

Nemtek's Druid LCD tackles this by sensing arcing and running the fence just below the voltage at which it starts, which keeps more energy on the fence than a conventional energiser manages. But the lasting fix is clean, sound insulators and plants cut back, so the fence holds its voltage whatever the weather.

• The settings survive. Nemtek says the Druid LCD keeps its user and installer settings even if the battery runs completely flat in a long outage.
• The battery may need time. A new, fully charged battery typically carries a Druid for more than 24 hours, depending on the fence's condition. After a long outage, it needs hours on the mains to recover.
• A service warning may show for a while. Nemtek notes that a service condition can appear briefly after a long mains failure; if it stays, the battery may need replacing, or something else needs a service.
• A mains-fail history on the Druid simply records that the power failed while you were away.

A JVA energiser flashes once for a tamper (its lid opened) and four times for a fault inside. A Nemtek Druid shows t when its front cover is, or was, opened. If nobody has opened it, take it seriously and check the fence is still on. An internal fault needs a repair: see energisers.

Call us when the energiser is dead with the mains on, when the fence won't arm or keeps switching off, when the condition stays low after the plants are cut back, or when a wire is broken or a tamper shows that nobody can explain. All our spare parts are genuine, and every repair comes with our six-month guarantee on our repairs. More on what we do is on electric fence repairs.

On the job card, give the energiser's make, what its display or lights show, and what changed: rain, a power cut, a storm or new plants. Same-day repairs are offered when the day allows, and a fence that's down at night is treated as urgent. No call-out fee when we do the work. If no work is done, a R650 call-out fee applies.