How to Repair Underground Electrical Wire

Repairing underground wire should be completed by the electrical power company or a licensed electrical contractor. Most states require that contractors have a digging permit to complete the required digging needed to locate and repair the electrical break. Digging without a permit can bring a hefty fine. Check with your local Utilities Protection center for digging guidelines in your area. Underground electrical conduits can become damaged for any number of reasons. Most times, the damage is due to aging wires and the environment. You will need to make repairs that are long-lasting and safe.

Check your state guidelines before you start digging.
  1. Ensure that the power to the broken wire is cut off and the breaker is locked out and tagged. Locate the break and carefully dig it up. With a razor, skin about three inches of insulation off of the wire. Keep the wire as clean as possible.

  2. Place each end of the stripped wire into the exothermic weld stove. Fill the stove with the powder according to the instructions for the size of wire you are repairing. Make sure you put the copper or steel in the bottom of the stove before you fill it with the powder. Turn away and yell, " Fire in the hole!" before you strike the powder.

  3. Allow the weld to completely cool before moving it. After cooling, carefully remove the stove and check the weld for cracks. If there are cracks or the weld does not hold, clean off the old weld and repeat the process until you have a solid weld. Take the solder and soldering gun and solder all around the open copper and weld until completely covered.

  4. Take the rubber tape and cover all exposed parts of metal, as well as two or three inches around the insulation. You may also take some liquid tape and seal all of the rubber tape to give your connection an airtight fit. Turn the power back on and check for continuity on both sides of your splice with an electrical ticker. Cover the connection after labeling it with a splice flag.


  • Digging without a permit in some state brings fines in the thousands of dollars.