How Do You Find a Broken Wire Underground?

How Do You Find a Broken Wire Underground?

Finding a break in a buried electrical wire requires specialized equipment and should be performed by a Licensed Electrical Contractor. The most common method uses a time-domain reflectometer (TDR), which sends a pulse down the wire and measures how long it takes to return from the fault — calculating the distance to the break with accuracy to within a few feet. Other methods include using a tone generator and receiver, or an insulation tester to confirm the fault location.

Common Causes of Underground Wire Faults

• Mechanical damage from subsequent digging, tree root growth, or frost heave
• Insulation failure in cable that was not rated for direct burial
• Water infiltration into a conduit joint or fitting
• Rodent damage in areas with ground squirrels or voles
• Original installation defect — splice made underground rather than in a proper junction box

The Repair Process

Once the fault location is identified, the repair typically involves excavating to the cable, assessing the damage, and either splicing the cable in an approved weatherproof junction box or replacing the entire run. Underground splices must be made in accessible junction boxes — they cannot be buried without means of future access. All underground repair work requires an ESA permit and inspection.

EZSMART troubleshoots and repairs underground electrical faults across Ontario. Contact us if you have a dead circuit that runs underground and suspect a buried wire failure.

Amir Azimipour

Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp