Fencyboy | 5 Common Causes of Low Voltage in Electric Fences

When you search online for "electric fence low voltage cause," you're really asking two questions: what's stealing my volts and how do I get them back quickly? Below are the five most common problems we see on farms, vineyards, and wildlife projects worldwide, along with suggestions to fix each one. We'll point out how a Fencyboy sensor can spot problems before animals (or predators) do, wherever it makes sense.

1. Grass, weeds, and wet brush are touching the hot wire

Why it happens: In the summer, grass and other vegetation grows quickly. The grass is wet from normal moisture or dew at dawn. When the grass touches the conductor, energy is sent to the ground.

How to confirm: Measure the voltage every week and see if it's decreasing. If it is, you have a problem.

Quick fix:

Mow and cut back vegetation along a path that's half a meter wide.
Build low barriers or add insulators that stick out to push growth away.

Use Fencyboy's trend-analysis tool to observe the voltage decrease over time. By analyzing the rate of decrease, you can estimate when it will be time to mow or cut back the vegetation again.

2. The grounding system isn't working properly

Why it happens: There aren't enough ground rods, the soil is too dry and sandy, or the clamps are rusty. This starves the energiezer's return path, so the pulse never completes a full curcuit. The quality of the grounding system is very important for the performance of the electric fence.

How to confirm: The fence reads low everywhere when under load (i.e. when animals are touching the fence).

Quick fix:

Position the ground rods in an area with high moisture levels in the soil.
Drive more galvanized ground rods into the ground (at least 3 meters apart and 2 meters deep). Do not use material which can accumulate rust because this will increase the resistance of the grounding system.
Use corrosion-free clamps to connect the ground rods to the energizer.
Use thick wire to connect the ground rods since it needs to carry the same current as the fence and should not be the limiting factor.

After improvements, watch Fencyboy's real-time graph climb instantly. If it doesn't, the fault lies elsewhere.

3. The energizer is not outputting enough energy

Why it happens: A mains powered energizer might simply be too small for the fence length. Battery powered energizers will not be able to deliver the same amount of energy once the battery is getting depleted.

How to confirm: For battery powered energizers, you can measure the voltage of the battery with a normal voltmeter. Try to measure the voltage during operation of the energizer because the voltage will increase when the energizer is not operating.

Quick fix:

Match energiser joule and voltage rating to fence length
Move solar panels into full sun
Replace batteries more often
Reduce interval between impulses to save energy (if your energizer supports this)

4. Cracked insulators, leaking fittings and loose wire clips

Why it happens: UV-aged plastic insulators, loose staples or metal wire clips create micro-arcs to posts. Each arc steals a few hundred volts from the system.

How to confirm:

Listen for a periodic clicking sound.
Walk the line at night—arcs often flash blue.
A hand-held fault-finder showing amps and direction lets you pinpoint the arc without waiting for dark.

Quick fix:

Replace damaged insulators with new quality UV-rated versions.
Tighten or swap out nail-on clips for screw-in models that hold tension better.

5. Physical breaks, fallen branches & gate shorts

Why it happens: Wildlife, tractors or storms pull wires loose; gates sometimes get left sitting on the ground.

How to confirm:

Visually inspect the fence for any breaks or unusual objects touching the wire.
Pay special attention to areas where the fence is close to trees or other vegetation.
Check the tension of the wire and ensure it is neither too tight nor too loose.

Quick fix:

Isolate the break by switching off sections.
Clear any branch that's touching.
Ensure that all gates are closed and properly connected. A loose fence wire touching the ground can cause the whole fence to be inoperable.
Every permanent gateway should have either underground cable or a well-insulated jumper lead so that opening the gate does not drop the voltage elsewhere.

Fencyboy's Sudden-Change Detection fires an immediate alert when the pulse amplitude drops from a normal operating voltage to a lower voltage.

Putting it all together

Low voltage is rarely a mystery; it's just hidden. By combining traditional maintenance tasks (like mowing, grounding, and checking equipment) with real-time analytics, you can transform hours of detective work into just a few data points and a ten-minute fix. You can install Fencyboy in less than ten minutes. Then, you can use it to monitor the voltage while you focus on other things.