Installing in-ground lights yourself is doable with careful planning, basic tools, and a focus on drainage, waterproof connections, and calling 811 before you dig.
Landscape lighting changes how your yard looks at night, but the hard part is getting the install right the first time. Digging into the ground means dealing with buried wires and water, so it pays to follow a solid procedure. Here is the sequence that works for low-voltage in-ground lights, based on manufacturer instructions and common-sense construction practice.
Planning the Layout Before You Dig
Start by marking every fixture location with a stake or flag. Look at where the light will fall and how close the fixtures are to walkways, patios, or driveways. Walk the route from your transformer or power source to each light so you know how much cable you need.
Call 811 at least 24 hours before you dig. This free service marks buried gas, power, and communication lines so you do not hit one. It is a legally required step on most US properties.
Choose well-drained spots for the lights. Installing in a low area where water pools after rain can flood the housing and kill the fixture early.
Digging the Hole and Preparing Drainage
The hole needs to be larger than the fixture housing.
Water is the biggest threat to in-ground lights. The standard fix is drainage aggregate at the bottom of the hole. Place 3–4 inches of pea gravel or clean crushed stone in the bottom. This lets water drain away from the housing instead of sitting against it.
Set the fixture housing or sleeve so the top rim sits about ½ inch above the surrounding grade. This prevents water from running into the housing when it rains or when you water the lawn. Use a level to make sure the rim is flat — an unlevel fixture creates a trip hazard and lets water pool on one side.
Avoid installing the fixture in a location where the ground slopes toward the housing.
Running Cable and Making Waterproof Connections
Low-voltage landscape cable goes in a narrow trench, typically 4–6 inches deep. Use a flat-blade shovel or a trenching tool to cut a clean slot.
Leave extra cable at each fixture — about 12 inches of slack or 30–50 cm of coiled wire buried below the fixture. If you need to move the light later or raise it for maintenance, that slack saves you from digging up the whole trench.
All electrical connections must be waterproof. Use direct-burial wire nuts or a sealed junction box specified for underground use. Strip the wires about ½ inch, twist them together with the connector, and wrap the joint with waterproof silicone tape for extra insurance.
If your fixture calls for a concrete mounting base, pour the base first, let it cure, and then mount the housing starting from the power input end. This is more work but gives the most stable platform for fixtures in high-traffic areas.
Once the connections are made, turn the power on at the transformer and test every light. Fix any that do not light before you backfill.
Backfilling and Final Positioning
After testing, backfill around the fixture housing with pea gravel or soil. Pack it gently so the housing stays level. Confirm the rim is still ½ inch above grade and the housing has not tilted during backfill.
For lights set in concrete, backfill with soil after the concrete has cured and check that the surface is flush with the surrounding ground. If you need to choose the right fixtures for your project, our roundup of tested in-ground lights covers models for driveways, paths, and accent lighting.
FAQs
Do I need a permit to install low-voltage landscape lights?
Most municipalities do not require a permit for low-voltage lighting under a certain voltage threshold, but local rules vary. Check your city or county building department before you dig.
Can I use regular wire nuts for underground connections?
No. Standard wire nuts are not waterproof. Use direct-burial wire nuts or a sealed junction box rated for outdoor underground use, and wrap the connection with waterproof tape.
How deep should I bury the cable for in-ground lights?
Low-voltage landscape cable is usually buried 4–6 inches deep. A narrow trench up to three inches deep may be acceptable for short cable runs, but deeper protects the wire from shovels and aerators.
References & Sources
- Ligman. “Installation Instructions for Inground Luminaires.” Describes drainage layer requirements, junction box sealing, and proper fixture mounting.
- Nortronic. “In-ground Light Installation.” Covers concrete mounting base method, hole sizing, and cable routing procedure.
- GM Lighting. “ILS-IG100 Installation Instructions.” Product-specific guide with hole dimensions, gravel depth, and slack requirements.