How to Wire Landscape Lighting | The Straightforward Way

Wiring landscape lighting means connecting low-voltage fixtures in parallel to a transformer plugged into a GFCI outlet.

Landscape lighting will transform your yard at night, but the wiring is what makes it work. A low-voltage system runs on 12 volts through a transformer that steps down your home’s 120-volt current. It’s a clean, safe project when you understand the sequence. The whole process is: mount the transformer, run the cable, connect the fixtures in parallel, terminate the wires at the transformer, test everything, and then bury the cable.

Where and How to Mount the Transformer

Start with the transformer. It must sit at least 12 inches above the ground, near a 120V outlet protected by a Class A GFCI. Keep it away from irrigation spray, in a well-ventilated spot. If you don’t have an exterior GFCI receptacle within a few feet, hire a licensed electrician to install one — the transformer should be connected to a GFCI circuit breaker.

When you’re ready to connect the low-voltage wires:

1. Remove the transformer’s bottom plate.
2. Select your tap. Most units offer 12V, 13V, 14V, or 15V — choose the highest that stays within the fixture’s rated range to compensate for voltage drop.
3. Route the secondary cables through the knockout holes.
4. Strip each conductor about 1 inch.
5. Connect one wire from each pair to the common tap and the other to your selected voltage tap.
6. Tighten the terminals securely.

Wiring Fixtures in Parallel, Not a Chain

Fixtures connect to the main two-conductor cable, not to each other. Standard two-wire 12V AC fixtures aren’t polarity-sensitive, so you don’t need to worry about which wire goes where — just that each fixture taps the same two main conductors.

Running a daisy chain from light to light is the most common mistake in this project. In a daisy chain, if one fixture’s connection fails, every fixture after it goes dark, and you also get uneven brightness from voltage drop. Wiring each fixture to the main trunk line keeps voltage steady and makes troubleshooting simple: each light is its own branch.

Use a wire gauge chart to size your cable based on total wattage and run distance. Longer runs need larger gauge wire. If you’re shopping for cable, our guide to the best 12-2 landscape wire breaks down the top options for medium and longer runs.

Testing, Burying, and Common Mistakes

Test the entire system before you touch a shovel. Turn on the transformer during daylight and confirm each fixture lights. This is your only chance to fix a loose splice while the wire is still in your hands.

Only after every fixture passes, bury the cable 6–12 inches deep. Direct-burial cable is rated for this, but even so, keep it below the frost line in cold climates to avoid damage from shifting soil.

Mistakes That Turn a Weekend Project Into a Dig-Everything-Up Job

• Daisy-chaining fixtures instead of wiring them in parallel
• Using undersized cable for long runs, causing dim lights at the far end
• Burying the cable before testing
• Leaving bare copper exposed at the transformer ports
• Mounting the transformer too low or within reach of irrigation spray
• Skipping GFCI protection entirely

A simple lighting plan on paper prevents most of these. Sketch the transformer location, the cable path, and each fixture point. Measure the run from the transformer to the farthest fixture — that distance, not the total cable length, determines your wire gauge.

The actual work is straightforward: run the cable along the path, strip each fixture wire, connect it to the main conductors with waterproof connectors, and repeat. The testing step is what separates a clean install from a frustrating one.