Repair Underground Wiring with a Splice Kit

As more and more homeowners add exterior lighting, receptacles, dog fences, and irrigation systems, there is a greater chance for damaging the direct burial, also called underground feeder (UF) cable, underground electrical wires. Instead of digging up the wire and replacing it, you can easily repair the wire in place with an underground splice kit. Underground splice kits contain a brass connector with a heat-shrink sleeve that will complete the connection and keep moisture out.  

Underground splice kits can come with a single conductor connector (top) to repair individual wires, or with a 4 conductor splice connector (bottom) to repair all of the wires in a cable. The 4-conductor splice has a plastic sleeve to isolate the connectors.

Splice kits can be purchased at home centers, online, and at electrical distributors for between $10 and $25 dollars, depending on the size and type of cable being repaired.

Tools and Materials

Electrician’s Pliers

Splice kit

Heat gun or hair dryer

Utility knife

Flathead Screwdriver

Hand trowel or shovel

Wire Strippers

Non-contact voltage tester

UF cable, if you need to replace a section of wiring

Instructions

Locate the circuit breaker feeding the underground wire and shut it off at the panelboard. If you recently hit the wire, it will probably be in a tripped position. If you cannot locate the break in the wire you should hire an electrician with an underground open/short locator to mark the location of the damage.

An Open/Short locator is not a device available to the do it yourselfer

1. With a small shovel, dig around the damaged electrical wire; about 12 to 18 inches on either side of the break. Depending on the installation, the wire can be from 6 inches to 24 inches below the surface. Use caution when digging so as not to damage the cable any further.
2. Test the wire or cable with a non-contact voltage tester to verify that there is no power on the circuit.
3. Cut the cable completely through if the wire has multiple conductors. If the cable is damaged over a large area, cut out the damaged area and cut a new piece of UF cable that is the same gauge as the original wire. Strip the outer cable sheathing back about 3 inches. Slide the heat shrink tube onto on side of the cable. Strip the conductors on each end of the wire.
4. Insert each conductor into a splice connector and match the conductor from the other end of the cable; black to black, white to white, and ground to ground. Tighten each screw in the connector.
5. Slide the heat-shrink tube over the splice connector. Heat the tube with a heat gun until it forms a tight seal around the connector. Some kits will have a sealant inside the tube that will come out of the ends of the tube when the seal is formed.
6. Restore power to the circuit and test the operation of the fixture or equipment.
7. Place the cable back into the ground and back fill the hole with the dirt that was removed. You may want to make note of where the repair was made in case problems arise in the future.