How to Safely Bury Underground Wires for Landscape Lighting

Installing underground wires for landscape lighting can enhance the beauty and ambiance of your outdoor space. However, improper installation can be hazardous. Here is a comprehensive guide on how to safely bury wires underground for landscape lighting:

Planning the Layout

The first step is to plan out the lighting layout. Consider the following:

• What areas do I want to highlight - pathways, trees, flower beds, etc? Make a list.

• Where will the light fixtures go? Mark their locations on a sketch of your yard.

• Where will the wires run? Map out the wiring paths between the fixtures and the power source.

• Try to minimize wire runs by placing lights closer to power.

• Group lights on the same circuit to use less wiring.

• Have a lighting plan before digging to avoid errors.

Choosing Underground Wiring

For burial, choose wiring designed for direct underground installation:

• Use direct burial cable for runs to individual lights. It has a moisture-resistant jacket.

• Use UF cable (underground feeder) for runs between fixtures. It can handle wet conditions.

• Avoid using indoor NM (nonmetallic) cable outdoors. It lacks waterproofing.

• Light-duty cords are also not suitable for burial. Choose sturdier wiring.

• For voltage-drop, opt for 10 or 12 AWG wire for runs up to 200 feet from the transformer.

• Use 14 AWG for shorter runs up to 100 feet. It reduces costs.

Digging the Trenches

Digging trenches properly avoids safety issues and damage:

• Locate any buried utilities first. Contact your local utility companies for identification to avoid cutting lines.

• Use a flat-edged shovel to skim the top layer and mark utility lines before digging further.

• Dig 8-12 inches deep for feeder lines to protect from lawnmowers or aeration.

• Go 4-6 inches deep for smaller branch circuit wiring to lights.

• Slope trenches slightly for drainage if wires cross planted areas.

• Avoid sharp rocks or debris when backfilling to prevent cable damage.

Burying the Wires

When burying the wiring, take care to:

• Keep wires ** grouped together and marked for the same circuit. Do not** crisscross different wire sets.

• Separate main feeder and branch circuit wiring at least 6 inches when running in the same trench.

• Lay cables loosely in the trench bottom. Do not cinch or staple tight.

• Backfill with dirt/sand mix without rocks to protect the jacket. Hand-fill around cables.

• Compact the fill in 6 inch layers to avoid settling later.

• Mark the wire path with buried warning tape for future utility work.

Making Connections

Follow safety procedures when making wire connections:

• Use waterproofgel-filled connectors for all splices and taps. Avoid non-waterproof twist-on connectors.

• Wrap connections in self-fusing silicone tape as additional protection from moisture.

• Mount fixtures and splice boxes above ground where possible. Use in-ground-rated units where needed.

• Connect to power through a GFCI breaker for safety. Use a separate circuit for lighting only.

By designing carefully, selecting the right components, preparing the site properly, burying the cables with care, and making weatherproof connections, you can install landscape lighting that will perform reliably for many years underground. Locating and marking all utilities first ensures electrical safety for your project. Following the above guide will allow you to safely install and enjoy your new low-voltage lighting system.