How to Wire Landscape Lighting | Low-Voltage Installation Steps

Wiring landscape lighting involves planning fixture locations, sizing a transformer with at least 20% extra capacity, running low-voltage cable, making parallel splices with waterproof connectors, testing every light, then burying the cable.

A low-voltage landscape lighting system transforms 120V household power down to a safe 12V, letting you run lights along pathways, gardens, and driveways without the hazards of line-voltage wiring. The whole job — from the transformer mounted on a GFCI outlet to the last fixture — follows a direct sequence that rewards careful planning and waterproof connections. Skip the layout step and you’ll be digging twice.

Planning Fixture Locations and Cable Routes

Sketch your property and mark where each light will go and where the transformer will sit. Low-voltage cable buries at only 6 inches deep, but you still want a clear route that avoids existing sprinkler lines, edging, and other utilities.

Leave roughly 18 inches of slack cable at each fixture location. That extra loop lets you reposition a light or trim a damaged wire end without cutting a new run. For the main cable feeding the transformer, leave extra length at both ends too; you’d rather trim off slack than splice on more.

Keep the low-voltage cable at least 12 inches away from any other electrical wiring or sources.

Sizing the Transformer for Your Lights

Add up the wattage of every fixture you plan to install. If you’re using six 4-watt path lights and a 12-watt spotlight, your total is 36 watts. The transformer you choose must be rated for at least 20% more than that — so a 36-watt load needs a 45-watt or larger transformer. Many installers apply the 80% rule: multiply the connected load by 1.25, or simply go 20–30% over the total.

For runs longer than 150 feet, step up to a lower-gauge cable (12 or 10 gauge) to reduce voltage drop. A 10-gauge main cable handles longer distances without dimming the last light on the line.

Unplug it before you start any wiring work.

Running Cable and Making Connections

Run the main low-voltage cable from the transformer location, past each fixture spot, with a little extra length at the end. Strip about 3/4 inch of insulation from the two conductors on the main cable where it will connect to the transformer terminals. For each fixture, strip about 1/2 inch from its wire leads.

Connect every fixture in parallel — the two fixture wires attach to the same two main cable wires, not daisy-chained light to light. Use waterproof connectors rated for direct burial. Silicon-filled wire nuts or brass barrel connectors both work; crimp or twist them clockwise until tight. Brass connectors resist corrosion better than plastic ones, which matters when the connector stays damp underground.

If you’re ready to buy cable, our tested landscape lighting wire recommendations cover the right gauges and jacket types for this job. A good 10- or 12-gauge direct-burial cable makes voltage drop less of a worry on longer runs.

Testing and Burying the Cable

Turn the transformer on before you bury anything. Walk every fixture and confirm it lights up. A light that stays dark means a loose connection, a stripped wire that didn’t make contact, or a bad fixture — all easier to fix now than after you’ve shoveled dirt back.

Once every fixture works, unplug the transformer again and bury the cable 6 inches deep. Tuck the slack coils under the fixtures and bury the main run in a straight trench along your planned route. Avoid sharp bends that can crush the wire; jagged or crushed cuts create resistance and heat over time. Tamp the soil back gently.