How to Safely Splice Underground Low-Voltage Landscape Lighting Wires

Introduction

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:

Wire connectors or splices rated for underground use - Regular above-ground connectors likely won't hold up when buried. I need to use connectors specifically designed for underground applications, such as 3M DBR/Y-6 connectors.
Electrical tape - For extra protection, I'll wrap all splices with electrical tape. Use self-fusing silicone tape for best water resistance.
Wire strippers - To strip back the wire insulation properly.
Wire cutters - To trim wire ends.
A flashlight - For seeing inside underground boxes or to trace wire runs.
Gloves - For protection when working with wires.
Safety glasses - For eye protection.

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:

Strip back insulation - Using my wire strippers, I'll strip back approximately 1/2" of insulation from the ends of the existing and new wires I'm splicing. This exposes the copper conductors.
Clean wires - I'll gently sand the exposed copper strands with emery cloth or fine-grit sandpaper to remove any oxidation and ensure a good connection.
Twist strands - Using pliers, I'll twist the exposed copper strands tightly together to prevent stray strands from causing issues.
Stagger splices - When splicing multiple wires, stagger where they are joined to avoid a bulky cluster.

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:

Wrap each connector with electrical tape, stretching it tight and overlapping at least 50% with each pass.
Consider injecting silicone sealant into the connectors for added waterproofing before taping.
Place splices in plastic bags or moisture sealant packs before burying in the ground.
Test splices with a continuity tester to confirm conductor integrity.

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.

Conclusion

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!