Invisible Dog Fence Troubleshooting – How to Locate and Fix a Break in Your Underground Dog Fencing

broken underground dog fence wireInvisible dog fences are a great way to keep your pet safely within the boundary of your yard for those people who don’t want to install a backyard fence. The only time there is a problem is when it quits working. Since the majority of the hidden dog fence is underground, locating a broken wire can be a challenge.

How an Invisible Fence Works

When you install an invisible fence, special boundary wire is buried around the perimeter of your yard, and the two ends are connected into a transmitter box in your garage or house. When completed, it’s like a big loop. The system works by producing a radio signal from the fence transmitter that is sent out through the buried wire. The dog wears a collar that contains a receiver. When the dog approaches the underground pet fence a warning beep goes off. If he gets too close he will be given a small electric shock.

The wiring used in underground fencing for dogs is like the kind of wire used in alarm systems. When the wire breaks, an alert is triggered in the invisible fence transmitter box in your home. Most boxes have a loop indicator light or an alarm that will go off if the loop is broken and the system is not functioning.

Confirm the Break

confirm break

If your invisible fence control box has a blinking light or emits a warning beep, the first thing you want to do is verify if you truly have a break. Begin by making sure the dog fence boundary wire is securely connected into the transmitter box. Next, check the transmitter for damage from electrical surges such as a lightning strike. To do this turn off the power then disconnect the two dog fence wires from the invisible fence transmitter. Next put a small piece of wire or paperclip into the jacks where the wires had been connected. This creates a mini-loop. If the alarm stops, the fence transmitter is working and you have a break somewhere out in the yard.

Another way to verify that there is a break is to use an ohmmeter and check the resistance on the disconnected wires. If there is no resistance the wires are continuous and there is not a break, meaning you may have a problem with the transmitter itself.

Locating the Break in an Underground Pet Fence

Assuming your underground fence transmitter box is working properly, and there are no nicks in the exposed wiring running up to the box, there are a few different ways to go about locating the break in the buried wire.

Check the Backyard for Recent Digging

The most common cause of severed fence wiring is digging in the yard. Power tools such as a rototiller, aerator, edger, or even a lawnmower can slice the wire in half. Burrowing rodents such as moles or squirrels can also separate the fence wire. By walking around the boundary of the underground fence and eyeballing it you may get lucky and find the fracture right away.

Wire Break Detector

wire break locator

Another options is to use a wire tracker or underground cable locator. Primarily used by irrigation contractors and utility workers, professional grade wire and sprinkler valve wire trackers utilize a powerful transmitter and sensitive receiver to locate irrigation wires and detect damage to underground cabling. They transmit an easy to hear beeping signal that is tracked by an extra long receiver. Follow the beeps with the receiver using the visual meter, external speaker, or a headset. Available online, these devices cost a few hundred dollars.

A less expensive version is the PetSafe wire break locator.  Although less expensive, it only locates complete breaks and not partial ones.



RF Choke and an AM Radio

connect rf choke

A less expensive option is to use an RF choke and a cordless or battery-operated AM Radio to locate the break in the invisible fence wire. An RF choke, or radio frequency choke, is a device designed to block higher frequency signals while permitting lower ones to pass through. You can find them in an electronics supply store such as Radio Shack or online.

To begin you will need to attach the underground fence wiring to the leads of the RF choke, one wire per side. Next plug the RF choke into the transmitter in the same place where you disconnected the fence wires. This will serve two purposes:

• To close the loop and allow the invisible dog fence transmitter to continue sending a signal to the fence even though it is broken.
• Make the signal your transmitter broadcasts clearer to your radio.

After you’ve attached it, re-establish the power to the underground fence transmitter box and set the intensity of the signal to high. There should be a numbered dial somewhere on the transmitter. Just don’t forget to turn it back down when you’re done or else your dog will get a real zap!

Turn on the AM receiver and tune it to the transmission frequency of the fence. You can locate this information in the owner’s manual. If you cannot find your invisible fence manual it may be available on the company’s website or through a Google search.

If you’re still unsure, just tune the radio to the bottom of the AM range and slowly turn the dial upward until you hear the signal. It will sound like fast beeps or rapid tapping when tuned in perfectly, and like static that gets louder as the radio passes over the wire when tuned in close, but not right on. Many models can be heard in the 530 kHz to 600 Khz range.

Searching for the Break

Walk around the perimeter of your invisible fence system while holding the AM radio antenna about three feet above the ground. As long as you hear the signal, the fence is operational. When you come upon an area where the signal stops for a few feet, this is probably where your break is located. Mark this spot with a flag or stake and continue on until you have checked the entire fence. There could be more than one break.

Digging up the Broken Wire

Once you’ve completed your inspection of the fence line you will need to dig up the spots marked as possible broken wire locations. Use whatever tool you like, but be careful not to nick or cut the wire.

After you expose the wires, use the radio to double check the signal on both wires. No signal on one side indicates that there is another break further down the line. If you have a signal on both sides connect them temporarily with a piece of wire, run inside and disconnect the RF choke and reconnect the invisible fence wires into the transmitter. If the alarm turns off then you have found your break.

Fixing the Break

fix break

The final step is to connect the broken dog fence wire in a way that is secure and weatherproof. If the break is large you will need to splice in some extra boundary wire to complete the connection.

One way is to use a weatherproof wire nut. They are filled with silicone to seal the twisted wires. You will need to strip a half inch of the insulation off of each side of the broken wires, then twist them together with the waterproof wire nut.

Another method is to use a direct burial splice tap or underground splice kit . Designed for splicing underground wire connectors and moisture-sealing two or more conductors for remote control circuits in irrigation and landscaping, you can find these in electrical wholesale and home improvement stores and online.

Finding the break in your hidden dog fence and fixing it is a great do it yourself project. The tools needed are few, the cost is minimal, the money saved is great, and the satisfaction of a job well done is priceless.

6 Responses to “Invisible Dog Fence Troubleshooting – How to Locate and Fix a Break in Your Underground Dog Fencing”

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  3. […] wire wrapped around a 1/2 inch cylinder.  I’m supposed to attach this to two points in the invisible fence transmitter, then use an AM radio tuned to a frequency without a station and walk the fence line to find the […]

  4. […] installed.  Our dogs, a golden lab and doberman, keep getting out!  I’ve looked in the invisible fence manual and think maybe we have a break in the underground boundary wire.  The manufacturer suggests […]

  5. […] to keep our two Siberian Huskies in the yard.  Yesterday I walked out into the garage and the underground fence transmitter box was beeping.  I checked the troubleshooting section of my owner’s manual and it said I have […]

  6. […] am looking for the the name of that wand-like tool that you can use to walk around the yard and detect a break in the underground wire of an invisible dog fence. It works much like a metal detector only it emits a signal over the underground wire but when it […]

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