Back Button

How to Splice Underground Sprinkler Control Wiring

Heath Robert

Almost all sprinkler wires are shielded to protect them from the elements when installed underground. It's possible to splice these wires together to extend the wiring, while maintaining a watertight connection. To accomplish this, you must use grease caps.

Sprinkler wiring can be spliced together using grease caps.

These caps are designed to seal the connection with a grease product that protects the connection point underground. These grease caps are designed specifically for sprinkler systems and low-voltage underground wiring.

  1. Place about 1 inch of one end of the wire that's to be spliced inside the wire strippers and pull back to expose the bare metal connection.

  2. Place the other wire into the strippers and pull back to expose the other side of the connection.

  3. Hold both ends of the wires in one hand next to each other, with the tips at the same point.

  4. Twist the wire together tightly with the other hand until the wires are joined.

  5. Place a wire connector from the grease-cap kit onto the end of the exposed wires and twist it clockwise until tight.

  6. Push the connector into the grease plug all the way to the bottom to allow grease to pile over the open end of the connector.

  7. Smooth out the grease over the connector with your finger until the connection is submerged in grease. Close the cap on the grease plug, and repeat the process for any other wires that need to be extended.

  8. Warning

    Always turn off the main electric breaker when working with live wires.