How to Find a Break in an Invisible Dog Fence?

Last Updated on July, 2024

An invisible fence is an effective fencing system to keep your pets safe within your yard. But no pet containment system is perfect. They come with their fair share of drawbacks.

Some of which are frustrating. Like when you face an underground break in the wire. Yeah, I know the feeling! The most significant strength of the system becomes a flaw.

So how to find a break in an invisible fence? It is invisible. You can’t even see it.

Fortunately, it is not as complex as I made it sound (wink, wink). Although you don’t need a miracle or a magic wand, you need some tools and patience to hack it.

Quick Summary

There are several methods that can be used to find and fix a break in the wire, including a visual inspection, the short looping method, the short circuit method, and the spark plug method.

Once a break is located, it can be fixed by splicing the broken wire and using an underground fence splicing kit, or by replacing the entire section of wire if it is too short.

The spark plug method and the RF choke method are DIY options for locating wire breaks without using specialized equipment. Finding a break in the wire requires patience and thoroughness, but with the right tools and techniques, it is possible to successfully fix the issue.

How Does an Invisible Fence Work?

a dog wearing invisible fence collar and sitting on the ground

Before we go down to the nitty-gritty details of how to find a break in the underground dog fence wire, it will be much helpful to know how they function. 

As the name already suggests, all invisible fences operate out of sight. Although physical components are involved, the fence is INVISIBLE to our eyes.

A traditional invisible fence involves burying a series of electrical wires underground across the whole perimeter of your choosing. This buried wire is connected to a mounted radio transmitter with a power source. 

The perimeter will now be able to communicate via radio signals with the dog collar, which comes as a part of the system kit.

As your dog nears the invisible fence perimeter, a beep tone is sounded as a warning telling your dog not to go ahead. If your dog ignores this and moves forward, a mild electric shock is delivered to your dog via the collar when crossing the boundary.

Proper training will help your dog understand the boundary and stay within the fences. Click here to check out the guide on “how to train your dog for an invisible fence“.

Also, read our complete article on how does an invisible dog fence actually work.

Verifying a Wire Break in Your Dog Fence

Dog invisible Fence broken wire

How do you even know if it is a wire break? For starters, your control box will be beeping and flashing in case of a wire break. And then you may notice your dog’s receiver collar is no longer reacting when at the invisible fence line.

So, did you notice signs of a possible wire break? Then, let’s track that pesky wire break and restore your invisible fence to working order.

I recommend you start with the simplest and easiest method for this activity. Going all technical and electrical to resolve the issue fast only works for some.

Visual Inspection- Examining Uncovered Ground Wires

Dog invisible Fence boundary wire

Do a physical check of your yard. Start from what you can spot with your own eyes. Look for wire splits, frays, or any visible damage.

This process is relatively easy if you have set up the boundary wire on your ground surface rather than a buried underground wire. If not, it can be time-consuming. 

But here’s how you can find a break easily:

  • Start following the twisted wires coming out of the transmitter. Walk around the perimeter.
  • Look for any signs of a possible wire break in areas where it is likely to happen. Odds are you’ll find it in places like mowing, weed whacking, or regular gardening.
  • Check for vehicle tracks, holes of burrowing animals, fallen brushes, uprooted roots, or overgrown shrubs. Pay attention to heavy traffic areas like pathways and sidewalks.
  • Still, looking for a break? Check where your wire connectors or splices are located. They could have been pulled apart.

I know it’s a painstaking process. But this is the best above-ground wire break detection for an average user.

This easy method can verify both: the presence and the precise location of the broken invisible fence wire.

Short Looping Method With an Extra Wire

The theory behind performing the short looping method is to check the functionality of your dog fence transmitter.

It eliminates the suspected malfunction of the transmitter.

You create a short loop of your dog fence wire using extra wire.

And connect it to the transmitter to see if it is still beeping. 

How to Perform a Short Loop Test?

a human holding small piece of the dog fence wire
  • Unplug all wires connected to the transmitter 
  • Cut out a small piece of the dog fence wire to use as a test wire. Around 12 inches will do. You can also use a stretched-out paper clip as the test wire.
  • Strip a part of the insulation off both ends of this test wire.
  • Now connect the ends of this test wire to the terminals from which you disconnected wires. It should create a small loop. 
  • Now connect the power cable and power up the transmitter.

The control box beeping during the short loop test means that there may be an issue with your transmitter. If the beeping stops, it is likely a broken wire in your invisible fence. 

You can check your dog’s collar using the short loop test if the beeping stops during the short loop test.

  • Make sure the collar has fresh batteries inserted. 
  • Set the lowest range on your transmitter. 
  • Hold the short loop a few inches away from your dog’s receiver collar.
  • The collar should sound a beep when held next to the test wire. 

If you are a person experienced in handling small electronics, try this method first. It saves time.

But I recommend you start with the visual inspection of your yard. It will give you an idea of how many wire breaks there are and may prevent future breaks if you do come across something amiss in your boundary line. 

Related article: Invisible Fence Troubleshooting

Testing Wire Continuity With Multi-meter

a human holding Multi meter wire

A multi-meter will help you test the functioning of the main loop. Multi-meters are available to purchase from any hardware store.

How to Test Continuity in the Underground Wire?

  • Start by setting the multi-meter on the continuity setting. You can do this by turning the device dial around.
  • Next, touch the metal legs of the multi-meter to the ends of the twisted fence wire.
  • Now listen to the beeping of the multi-meter.

If your multi-meter beeps, that means there is wire continuity in your underground fence wire. Your loop is working correctly. And no wire breaks are detected.

Short Circuit Method

This method is similar to the short-looping method. Instead of an extra wire, we use the electric dog fence wire. 

You test the wires from the transmitter to the underground dog fence line by shorting the loop at the transmitter.

Steps for Using the Short Circuit Method

  • Follow the transmitter wires, which go underground at each end.
  • Cut the wires at this point and short them together. Create a loop.
  • The loop created will send a radio signal to the transmitter. You can establish that the issue is in the buried underground wire if the transmitter doesn’t beep.

Here’s how to set up an invisible dog fence properly to avoid these breaks.

Detecting the Precise Location of the Wire Break in Your Dog Fence

Wire Break Locator Method

A wire break locator kit can be used to detect a broken wire underground. It comes with an AM radio and a mini transmitter. 

How to Use the Wire Break Locator Kit?

  • Begin by unplugging the transmitter of the underground fence wire.
  • Connect one of the alligator clips of the wire break locator transmitter to the underground wire. The other clip has to be grounded in wet dirt using a screwdriver. 

Use the instruction manual of the wire locator kit for detailed instructions on which clip goes where and the grounding method.

  • Next, you should turn on the transmitter of the wire locator. The transmitter gives power to the buried wire of the underground dog fence. 
  • Now turn on the AM radio that comes with the kit. And adjust the volume. The lower AM range can detect radio signals emitted by your electric dog fences.
  • The signal of the fence can range from 530- 700 kHz. Adjust the frequency from 530 kHz onwards to find your dog fence signal. Make sure no radio station channel is active on it.
  • Now walk the underground wire path while swinging the radio close to the ground surface.
  • Radio signal picks up on electrical current interference. You will hear a combination of two sounds as you walk the perimeter line. The sound switches from two to one or gets softer and disappears at a wire break point.
  • Single break- the sound switches from two to one
  • Multiple breaks- the sound gets softer and disappears

I recommend you watch tutorial videos on how to use the locator kit to be able to distinguish the sounds.

Spark Plug Method, AKA the am Radio Method

Don’t want to spend on a wire break locator? Then let’s improvise with a DIY broken wire locator method. 

You can find the wire break in an invisible fence using radio systems and a lawn mower.

The lawn mower acts as the transmitter, and the radio detects the break in the wire.

You will need a four-stroke lawn mower to provide sufficient charge and static from the wire underground—an AM radio with an antenna.

And an extra wire of around 20-30 feet in length. 

a human holding a radio near the invisible fence wire

Steps for Using Spark Plug Wire Locator Method

  • Make sure your underground transmitter is disconnected.
  • Connect one end of the extra wire to the lawn mower’s spark plug. Twist the wire a few times to make sure it is snug. Connect the other end of the extra wire to the underground dog fence wire. 

Any point works. You can connect it to a line break if you happen to come across one during your physical check. Or you can directly connect a wire going into the underground fence transmitter.

  • Turn on the lawnmower to a low-frequency static.
  • Get the AM radio tuned to 530 kHz. 
  • Now pass the radio over the fence line.
  • The static gets louder as you get closer to a break in the wire.

RF Choke Method

This broken wire locator method uses an AM radio and a RFC. RF chokes are available to purchase at any hardware store.

A radio frequency choke (RFC) is a small electronic gadget that blocks high radio frequencies while allowing audio and DC (direct current) to pass.

Steps for Using RF Choke Wire Locator Method

  • Disconnect the wires from the transmitter and replace them with the choke.
  • Turn the signal strength of the transmitter all the way up. Ensure there are no wire break errors when the choke is in place.
  • Now take the two ends of the detached wires and wrap them around on either side of the choke. The uninsulated part of the wire should touch the choke.
  • Now use the AM radio as instructed in the above methods. 
  • Walk down the path of your electric dog fence line. Listen to static from the AM radio.
  • An audible pulsing means- the wire is intact and no breaks are present.
  • Silent or soft pulsing means- a break in the underground wire is present.

How to Fix a Break in the Wire?

broken invisible fence wire
  • Dig up the underground wire where you found the breaks.
  • Strip at least ½ inch of the wire covering from the broken ends of the two wires.
  • Remove any dirt and clean the wire ends.
  • Twist the ends into a wire shape.
  • Using an underground fence splicing kit, connect them. Suppose the wire is too short; splice in another piece of new wire to create a wire bridge connection.

Here’s our complete guide to repairing an invisible fence wire step by step guide.

Final Words

No doubt, finding a break in the invisible fence wire is like looking for a needle in a haystack.

But you can make the task more manageable if you use the correct methods and follow through.

If you are considering replacing your fencing system, check out our article on the best invisible fence to guide you with your purchase.

Frequently Asked Questions

Using a strong electric dog fence wire system, you can avoid wire breaks in the future. A thicker wire with UV-rated HDPE coating and seven strand copper core is the best choice. They withstand long-term heat exposure. You can insert the wire into poly pipes or metal pipes for extra protection. 

You should also ensure your original splices and wire connections have a solid connection.

The wires should be buried in a 1- 3 inch deep trench. This is an ideal depth for adequate signal transmission and protection from lawnmower or other lawn activity damage.

No, an invisible dog fence does not have to make a complete loop. However, a complete loop will increase the voltage in the fence line because power is pushed in both directions making the fence more effective.

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Stefano Giachetti
Stefano Giachetti is always excited to share his knowledge and love of animals with you through our blog, IPetGuides. And he has always loved animals and has been blessed to have many pets throughout his life. Currently has a Pomeranian Dog Breed.

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