How to Install a Yard Light Post

Adding a light post is not difficult. If you've installed an interior light fixture, you should be able to tackle this project. You'll have to do some digging, but a rented power trencher makes the job easy. The wiring connections for a light post are fairly simple. You can buy a lantern with a photocell that automatically turns the light on and off or wire a switch.

Besides welcoming guests and helping to ensure a safe walk to your door, good exterior lighting deters prowlers. Most homes have at least one exterior light mounted near the front door. The illumination is useful near the house, but it quickly diminishes as you move out into the yard. A great way to light up the rest of the yard is to install a remote light post, which also acts as a decorative focal point and can serve as a marker to help identify your house.

As with any electrical project, check with you local codes department for specific requirements.

Selecting a fixture
Light posts are typically sold as two separate pieces — the post and the lantern. Most companies offer several lantern options and a few posts that fit all of their lanterns.

There are a few optional features to consider when selecting a light post. The first is a built-in electrical receptacle. This is a great convenience if you plan to display holiday lights or use corded yard tools near the light post. The second option is a photocell — a light-sensitive device that acts as a switch, turning the lantern on or off depending on the amount of daylight it senses. A photocell can save energy and bulb-replacement costs because you won't accidentally leave the light on during the day. Photocells can be built into both lanterns and posts, but you need only one to operate the light. So if you choose a lantern with a built-in photocell, you can select a post that does not include a photocell. Even if you use a photocell, you can still install a switch that allows you to manually turn off the light.

The final option to consider is the type of bulb the lantern will use. Most use either incandescent or fluorescent bulbs. Fluorescent bulbs offer energy savings compared with incandescents. Keep in mind that the fixture and photocell that you choose must be rated for the type of bulb you use.

Planning and design
Your first step in adding a light post is to determine the location of the light. You can't place a private light in the public right-of-way. Most cities require a minimum distance (2 to 4 ft.) between the street or sidewalk and any fixture that you intend to install. These restrictions will be identified when you apply for a permit.

Another consideration when choosing a location for the light post is the path back to the power source (usually your house). The shorter the distance, the less digging is required. Select a location that has the fewest obstructions in the path back to the power source. Avoid crossing under trees to prevent potential damage to root systems.

Next, determine where you will tie into your home's electrical system. An existing exterior receptacle is the easiest connection point. You can install an exterior receptacle in a convenient location by tapping into a basement receptacle and running cable through the rim joist. Another option is to enter the exterior wall in the same stud bay as an existing interior receptacle and then connect to that receptacle.

If you plan to control the light with a switch, you can locate the switch in a weatherproof box next to the exterior receptacle or inside the house or garage. We connected to a receptacle inside the garage next to the door.

Call Before You Dig
Checking for buried utilities is not just a good idea; it's required by law. Many utilities participate in a free "one-call" service that coordinates the check with all utility companies that may be affected. (Call 8-1-1 or visit the Call 811 Web site for details.) All you have to do is provide the project location and the date when you plan to dig. After the check, you will be required to begin digging within an approved time period. Besides enhancing safety, checking for buried utilities before you dig can save you money because if you damage any underground utilities that were marked incorrectly, the service that checked will typically pay for the repairs.

Digging the trench
Before doing any digging, you must apply for a permit and have your property checked for buried utilities. Once you know where it is safe to dig, begin digging a 6-in.-wide x 18-in.-deep trench from the light post location to the power supply. You can dig short runs with a hand shovel, but for long runs or tough conditions it is much more efficient to rent a power trencher.

Another option is to hire a contractor to lay the cable using a vibratory plow — a machine that slices through the soil and pulls the cable down into the ground as it moves forward. This service costs about $1 to $2 a foot, but it will not disturb the soil or sod nearly as much as other methods, which means less cleanup and yard repair when the job is done.

Whatever method you use to dig the trench, dig the last 3 to 4 ft. next to the house foundation with a shovel to prevent damaging the foundation.

Laying the cable
The cable you use must be rated for underground installation. Type UF (underground feeder) cable is rated for-direct burial. Some cities will also allow the use of Type TW (thermoplastic wet) wire as long as it is protected in rigid nonmetallic conduit.

Type UF 14/2 or 12/2 cable is most commonly used on residential jobs because it is easier, faster and less expensive to install than running wire in conduit. But there are situations when it is a good idea to use nonmetallic conduit for its added protection — for example, in areas where future digging is likely to occur, such as under a garden.

Roll out the cable in the trench, leaving enough excess on each end to reach the power source and light post connections plus a couple of extra yards — you can always cut off the excess, but you can't stretch the cable if it's too short.

We drilled a 1-in.-dia. entry hole through the garage wall above the foundation blocks. The cable must be protected by nonmetallic conduit from 12-in. below grade to where it enters the garage. Connect the conduit to an L-body fitting if you are going directly into the house (photo 1, below) or to a threaded male box connector if you are connecting to an exterior receptacle box. Fasten the conduit to the house with conduit straps, and seal any gaps between the conduit and the house wall with silicone or latex sealant.

Make a frost loop in the trench and then feed the cable through the conduit (photo 2). A frost loop provides slack for the cable so that connections aren't pulled apart during frost heave. Once the cable was inside the garage, we secured it to the nearest stud with cable staples and then to the receptacle box with a box connector.

On the light post end of the trench, the post base must be anchored to a concrete footing. We created a path for the cable through the footing by running 1/2-in.-dia. conduit through a tubular concrete form. Cut the form a few inches longer than the depth of the hole, and cut a 1-in.-dia. hole near the base of the form. Position the conduit in the form, make a frost loop with the cable and then feed the cable through the conduit (photo 3). Level the form and backfill a few feet of the trench to hold the form in position. Do not fill the rest of the trench until the project has been inspected and approved.

Fill the form with concrete, keeping the conduit centered in the form. Next, push the anchor bolts attached to the post base into the wet concrete (photo 4). Level the post base and let the concrete cure for at least 24 hours.

Making wiring connections
The light post must be protected by a GFCI. You can either tie into a circuit that is protected by a GFCI circuit breaker or install a GFCI receptacle. We replaced two receptacles with one GFCI receptacle and a single-pole switch to control power to the light post (photo 5). The power from the house runs through the GFCI receptacle to the switch and out to the light post.

Feed the UF cable through the post. Cut off the excess cable, leaving 12 in. of cable extending out of the top of the post. Cut back 8 in. of the outer cable sheathing, separating the three wires contained in the sheathing, and then strip back 1/2 in. of the white and black wire insulation.

If you're installing a receptacle or photocell in the post, this is the time to do so. Connect the power supply cable wires, lantern wires, receptacle wires and photocell wires (photo 6) as directed in the light post installation instructions. Secure the connections with wire caps, and wrap the caps with electrical tape. Insert the wires back into the post. Secure the lantern to the post with the supplied sheet-metal screws.

Lift up the post and lantern and carefully slide the post down into the post base, fitting the cable into the post. Secure the post to the base (photo 7).

Install a light bulb and test the fixture. If it is daylight outside, disable the photocell by covering it with a piece of electrical tape. Test the GFCI protection by pressing the test button on the GFCI receptacle. (Power to the lantern should be cut off.) Reset the circuit to resume operation by pressing the reset button on the GFCI. After the project passes the final permit inspection, the last step is to landscape over the trench and around the post.