Work Through It in Order
When an electric fence underperforms, the cause is almost always one of four things: the energizer, the battery/panel, the grounding system, or the fence line itself. This guide walks through them in order — no guessing, no random fence walking. Grab a fence tester, a battery tester and a screwdriver, and find your energizer type below.
Step 1 — Test the Energizer Itself
AC (plug-in) energizers
- If using an extension cord, it must be industrial-rated and no longer than 50 feet.
- Unplug the energizer.
- Remove both the hot and ground wires from the fence.
- Plug the energizer back in.
- Check voltage at the energizer terminals with a fence tester.
- Voltage within 20% of spec? Reconnect the wires and move to the grounding test (Step 3).
- More than 20% below spec? The energizer itself is suspect — contact the manufacturer with your model and serial number.
DC (battery) energizers
- Turn off the energizer, remove both wires, turn it back on and test.
- Voltage within 20% of spec → reconnect and go to grounding (Step 3).
- More than 20% below → turn off, remove the battery and test it with a battery tester.
- Battery low → replace or recharge it. Battery reads fine → the energizer is suspect — call the manufacturer.
Solar energizers
- Charge the energizer in the off position for at least three full sunny days before testing.
- Remove both wires, turn on, and test voltage.
- Within 20% of spec → reconnect, go to grounding.
- More than 20% below → turn off, remove the battery and test it. Low battery → replace; accurate battery → energizer suspect.
Step 2 — Check the Voltage Requirements
Compare your tester reading with the energizer's published specification. The number that matters is what the fence delivers at the far end of the line, not what the box claims with nothing connected. If the energizer reads fine but the fence doesn't, the problem is downstream — grounding, lead wire or the line itself.
Step 3 — Test the Grounding System
Many electric fence issues trace back to grounding — even a fence that worked for years can fail when soil moisture changes. A proper ground system needs at least three metal rods (copper, rebar or galvanized steel), placed 10 feet apart and driven at least 6 feet deep. To test:
- Lay a metal bar against the fence, about 100 yards from the energizer.
- Touch the hooked end of the fence tester to the top of a ground rod.
- Place the probe end into the soil.
Reading under 400 volts? Your grounding is fine — move to the fence line. 400 volts or more? Add more grounding: more rods, deeper rods, or in dry/sandy soil, a buried ground wire connecting the rods. See our grounding guide for the full setup.
Step 4 — Test the Lead Wire
Your electricity may be leaking into the ground before it ever reaches the fence:
- Turn off the energizer and remove the hot lead wire from the fence.
- Turn the energizer back on and test the lead wire.
If the lead reads significantly lower than the energizer terminals, electricity is leaking to ground — replace the hook-up wire with 20kV insulated wire and recheck. Similar reading? Move to the fence line.
Step 5 — Walk the Fence Line
If everything above checks out, there's no way around it — walk the line with tools and spare parts, looking for:
- Heavy or wet vegetation touching the wires — the most common voltage thief; clear a corridor under the line.
- Cracked insulators — replace any that leak current to the post.
- Rusty or loose connections — clean and retighten.
- Wire touching wood — grounds out the pulse; re-hang on insulators.
- Splices or jumpers no longer secure — a loose splice adds resistance.
- Faulty connections at gate openings — check the jumpers under gates.
- Metal objects within 4 inches of the line — can short the pulse.
Prevention Is Cheaper Than Repair
Most of these failures are preventable: keep vegetation off the line, check insulators and connections seasonally, and test the far-end voltage on a schedule — a fence you measure is a fence that works. For routine upkeep, our maintenance guide covers the full seasonal routine.