How to Safely Splice Underground Low-Voltage Landscape Lighting Wires

How to Safely Splice Underground Low-Voltage Landscape Lighting Wires


Splicing low-voltage landscape lighting wires underground can seem daunting, but with proper planning and materials, it can be done safely and efficiently. As the homeowner, I want to ensure any underground splices I make are watertight and will stand up to the elements to avoid shorts or other electrical hazards. In this article, I will walk through the key steps I need to take and considerations I need to make when splicing underground low-voltage landscape lighting wires.

Gather the Right Materials

Before I start any splicing, it's crucial that I gather the right materials to do the job properly. Here's what I need:

Locate Existing Wires and Boxes

Before splicing, I need to locate where I want to join the new wires to the existing ones. I'll use my flashlight to trace the existing low-voltage wire run from the fixtures back to the transformer and identify access boxes or other connection points along the way. If I can't find an existing box, I may need to install a new underground-rated box to house the splices.

Turn Off Power

Safety first! I'll locate the transformer powering the lighting system and turn off the power at the breaker before doing any work. I want to be absolutely certain the wires I'm handling aren't live. I'll double check with a non-contact voltage tester.

Prepare the Wires

With the power off, I can access my connection point and begin working with the wires. Here are the key steps involved:

Join Wires with Approved Connector

With clean, stripped wire ends ready to go, I can join them together with my underground-rated connectors. I'll securely fasten the wires into the connector following the manufacturer's instructions so no copper is exposed. Tight connections are key for optimal conductivity.

I'll double check that connector screws or nuts are fully tightened with no copper peeking out.

Waterproof Connections

Underground connections need extra protection from moisture. Here are some tips:

Restore Power and Test

Once all splicing is completed, I can restore power at the breaker. I'll turn the lights on and walk the path of the lighting system, making sure all fixtures are functioning properly. If there are any issues, like shorts or power drops, I may need to check my connections and re-splice if necessary.

With good materials, careful technique, and adequate waterproofing, I can be confident my underground lighting splices will hold up for years to come. Taking the time to do it right will save me from endless electrical headaches down the road.


Splicing low-voltage landscape lighting wires underground doesn't have to be a daunting task. With the right connectors and preparation, I can make reliable, long-lasting splices. The keys are using approved underground materials, cleaning and prepping the wires thoroughly, staggering connections, tightly fastening connectors, and properly waterproofing each joint. With care and attention to detail during the process, I can install beautiful and functional landscape lighting that will stand the test of time. My yard will shine bright for many years to come!