How to Install Outdoor Landscape Lighting

Create a lighting plan by examining the exterior of your home and finding a household outlet. Then, measure from the outlet to where you'd like your lights to end. You will need a power cable that's this length or longer. 

Editor's Tip: Be sure to follow the manufacturer's instructions with regard to the maximum wattage you can run from the power supply.

Following your landscape lighting plan, mark the cable locations in your yard with agricultural lime. This step allows you to plan the placement of the cable so it avoids natural barriers. Pinpoint the fixture locations with dowels or stakes.

It's safe to lay low-voltage cable directly on the ground, but it's more attractive if it is buried. If you decide to bury the cable, dig a narrow trench along the chalk line. Place the cable in the trench, leaving a 1-foot loop at the transformer and a loop at each fixture location. If cable stretches along the underside of a deck, for example, you can staple the cable in place, leaving loops for all connections. Take care not to puncture the cable when stapling it in place.

Cut through the cable to prepare for attaching a light fixture to the circuit. Study the cut end of the cable; you'll notice two separately insulated conductors. Cut or pull the cable apart so the two conductors can be stripped. Using a wire stripper, strip the insulation off the conductors to expose 3/4 inch of wire at the end. Note that you need to strip the cable that leads into the light fixture as well as the cable that leads away from the fixture. Strip the insulation off the fixture's wires to prepare to connect to the low-voltage wire. (Practice stripping the insulation so you can strip it cleanly without nicking the wires.)

To make the wire connections that bring power to a light fixture, take one stripped conductor from the 12-volt cable leading into the light fixture and one stripped conductor from the 12-volt cable leading away from the light fixture. Hold the wires side by side, twist them together to ensure a good connection, and screw a wire nut over the wires. Make sure that no bare conductors are exposed and that all wires are locked in. Repeat this procedure with the remaining three wires.

Since this lighting is outdoors, you need to consider the weather. For a weathertight connection, wrap electrical tape around the cable to seal the joint between wire nut and cable. Wrap the tape in several layers to ensure a safe seal. 

The cable should end at a light fixture. When wiring the last light fixture, twist two pairs of wires together (one pair from the light fixture and one pair from the cable) rather than the three pairs needed for a light fixture wired in place along the circuit. Do not run the cable beyond the last light fixture. If you decide to add fixtures later, simply unwire the last connections and add a new cable.

Editor's Tip: If your transformer will be located outside, make sure it is watertight. Do not plug the transformer into the outlet until all wiring connections are complete. Make sure the transformer is protected by a fuse or circuit breaker.

After wiring the fixtures in place, connect the cable's two conductors to the transformer. Wire one conductor to the wire marked 0, and wire the other conductor to a 12-, 13-, or 14- volt line. If you are bringing several cables into the transformer, always connect one conductor from each cable to the 0 line and wire the other conductor to a cable.

After all wiring connections are made, plug the low-voltage outdoor lighting transformer into a timer (if you want your lights to come on and go off automatically at various times), and plug the timer into the outlet. Check all the system fixtures to make sure each is operating correctly. Adjust the direction of lights, if necessary. The location of a fixture can be easily adjusted without rewiring if there is enough extra cable near the fixture.

If a fixture does not light, check the bulb first. If the bulb is good, check the electrical connections. Dim bulbs are an indication that the bulb is not receiving enough electricity; make sure the length of the cable run does not exceed manufacturer's recommended length. If the entire system fails to light, check the circuit breaker on the transformer.

Once everything is in place, the fixtures are functioning, and the light is directed the way you want, you're done. Bury or staple down excess cable from loops. Wait for the sun to go down, and admire your hard work.