Electric Fence Not Working? Common Problems & Solutions
By JD Gates Pretoria | Technical Guide | Published: 8 July 2024
An electric fence that has lost its charge provides a false sense of security. Here are the most common reasons an electric fence stops working and how to diagnose them.
Problem 1: Energizer Not Powering On
Check the mains power supply — a tripped circuit breaker is a common cause. If the breaker is fine, check the energizer fuse (most energizers have a replaceable glass fuse on the back). A blown fuse indicates a surge event; replace the fuse and test. If it blows again, the energizer may have internal damage.
Problem 2: Fence Has No Voltage at the Wires
If the energizer is on but the fence wires are not live, there is likely a short circuit — a strand touching earth somewhere along the fence. Common causes: vegetation touching the wires, a broken post allowing strands to droop to the wall, or a damaged isolator. Walk the fence line and inspect for vegetation contact or broken insulators. Clear the fault and retest.
Problem 3: Fence Voltage is Too Low
A fence reading below 3,000 V at the end of a long run indicates excessive strand resistance — usually from multiple small short circuits or heavy vegetation growth. A properly cleared fence should read 6,000–8,000 V at the end of any run. If voltage is low after clearing all vegetation, the energizer may be underpowered for the fence perimeter length.
Problem 4: Fence is Live but Alarm is Not Working
Check the earth loop connection — this is the alarm monitoring function. If the earth loop is broken (e.g., a cut in the earth return wire), the alarm will not trigger correctly even though the fence has voltage. JD Gates provides full electric fence diagnostic and repair services across Pretoria. Call 012 012 6285.