How to Safely Bury Electrical Wiring in Your Garden

Introduction

Installing low-voltage electrical wiring in your garden can allow you to conveniently power landscape lighting, water features, or other outdoor accessories. However, burying electrical wiring improperly can be a safety hazard. In this guide, I will walk through the key steps I take to safely run electrical wiring underground in my garden.

Gather the Right Supplies

Before starting any digging, you'll need to gather the appropriate supplies:

Direct burial-rated electrical wire - Regular electrical wire can become damaged when buried, so use wire specifically rated for underground use. I prefer 12/2 or 14/2 gauge, 2-wire cable.
Waterproof wire connectors - Use connectors approved for wet locations to join your wires. I like twist-on wire nuts or moisture-sealed connectors.
Conduit - For some portions of the wire run, conduit protects the cables. Use schedule 40 PVC or flexible nonmetallic conduit.
Burial warning tape - Red warning tape alerting future diggers to the presence of buried cables.
Landscape staples - To secure wiring against walls or surfaces. I use galvanized metal staples.
Digging tools - A round point shovel makes it easier to dig a narrow trench.
Gloves & safety glasses - Protect your hands and eyes when digging and handling wire.

Plan the Wiring Route

Before digging, map out the full route for your buried wire to run. Consider these factors:

Where does the wiring need to connect above ground? Plan for the wire to surface at the power source and endpoint connections.
How deep can you dig trenches? 6-12 inches is ideal for most electrical cable burial. Ensure no conduits, plumbing, etc. are present.
Are there any obstructions? Design the route to avoid large tree roots, conduits, or boulders.
Are pavement or walls present? You may need to bury conduit under driveways or use landscape staples to attach wiring against walls.
Mark the route with spray paint or flags. Adjust if needed before digging.

Dig a Trench

Dig a trench along the planned route using a shovel. Make the trench deep enough to meet burial depth needs:

For most small electrical wiring, a 6-12 inch deep trench is sufficient.
Where wiring passes under paving, the trench should be at least 12 inches deep to prevent damage.
In some areas, local electrical code may dictate a minimum depth.

The trench should be 2-6 inches wide - enough to fit your wiring, conduit, and spacers while still allowing you to backfill soil easily. Remove large rocks or debris as you dig.

Run Wiring Through the Trench

With the trench fully dug, it's time to install the wiring:

Use PVC conduit to protect any wire running under paved areas. Also use conduit when passing through cinder block or porous soils.
Install wiring at the bottom of the trench, positioned evenly across the width.
For long cable runs, use plastic spacers every 5-10 feet to prevent wires from shifting before backfilling.
At walls or surfaces, use staples to attach wiring neatly in position 4-6 inches deep.
Ensure no stress on connections by leaving slack at endpoint access locations.
Use waterproof connectors to splice any necessary wire junctions.

Backfill and Bury the Wiring

Once wiring is installed in the trench, backfill with soil to cover:

Before backfilling, run a final check to ensure wires remain positioned properly in the trench.
Partially backfill to 2-3 inches above wires, using soil with no large debris. Tamp down gently to compact.
On top of the backfill, lay the red burial warning tape 2 inches down to alert future diggers.
Finish backfilling fully up to ground level. Mound extra dirt to account for settling.
Dispose of any leftover debris appropriately. Remove tools and work materials.

Inspect and Test New Wiring

Before using your new electrical wiring, it's critical to test it:

Visually inspect that ground is level with no evidence of wires protruding.
Use a multimeter to check for unintended power at endpoints and along the route.
When power is connected, test operation and check for faults.
Consult an electrician immediately if there are any issues identified.

Follow Safety Best Practices

Working with electrical systems can be hazardous. Protect your safety:

Disconnect power at the breaker before starting work. Verify it's off!
Call 811 before any digging to identify buried utility lines.
Never run wiring underneath high-voltage lines or near flammable materials.
Use GFCI-protected circuits or outlets for all outdoor wiring installations.

With proper planning, materials, and technique, burying low voltage wiring in your yard can be straightforward. Take it slow, be cautious of hazards, and your hard work will pay off with a clean, professional outdoor lighting or accessory setup. Let me know if you have any other tips for burying electrical wiring based on your experiences!