Low-voltage systems make lighting a deck both safer and easier.
Time Multiple Days
ComplexityBeginner
Cost$101–250
Introduction
Plan and install a low-voltage lighting system to light up your deck. No electrical skills needed; you simply plug the system into an existing outlet. It'll highlight deck features without glare and is safe and easy to install.
If late summer nights outdoors are calling you, get ready to pull up a lounge chair. Your deck can be the setting for many relaxing evenings— the key is to add lighting that casts a nice glow over sitting areas, highlights landscaping features and illuminates steps and walks.
Low-voltage deck lighting systems do this well and they’re safe and easy to work with. Unlike with standard household voltage, the transformer that powers them simply plugs into a receptacle. While there are ready-made low-voltage deck lighting kits available, in this article, we’ll show you how to plan a system for your deck and how to install the transformer and fixtures.
Tools Required
- 4-in-1 screwdriver
- Circular saw
- Drill/driver - cordless
- Hammer
- Pliers
- Wire stripper/cutter
Materials Required
- Cable
- Cable staples
- Low-voltage lighting fixtures
- Transformer
- Waterproof wire connectors
Project step-by-step (18)
Step 1
Draw up a low-voltage deck lighting plan
There are several types of low-voltage deck lighting fixtures, each designed for special uses. To decide on which light fixtures to use where, first draw a rough plan of your deck as shown in Figure A below. On the plan, note at least the following key features: stairs, sitting and congregating areas, nice features such as railings and plantings and traffic paths. Also note the location of nearby receptacles that can be used to plug in your transformer.
Take your deck plan to a lighting showroom to select specific fixtures to light each feature. Ask a salesperson to help. Mark the selected fixtures on the plan. Note that a single fixture can sometimes handle several tasks. Next position the transformer on the drawing next to an existing receptacle. If no receptacle is nearby, you’ll have to install one. A receptacle controlled by an inside switch is the most convenient setup.
Draw lines to connect the fixtures to the transformer. Minimize the amount of wire you’ll need by connecting multiple fixtures to a single circuit wire. This may affect the size wire you need. Select a transformer size that provides at least 25 percent excess capacity. Also decide what features you want with the transformer.
Step 2
Connect to a power source
First, run the wiring. Each circuit requires a cable that is made up of a pair of wires. Calculate the total length of cable needed and buy it as one piece. Plan on cutting specific lengths on the job.
Always try to route wires out of sight. Run the cables under the decking. If a cable must be visible, staple it into a corner or on the least conspicuous surface.
Use insulated staples to fasten the cables to wood members at 2-ft. intervals. The low-voltage wire and the waterproof wire connectors must be buried 6 in. deep into the ground.
Step 3
Wire the fixture
Most stair lights have to be connected through the back. Bore a 1-1/2 in. hole from the front side and pull a loop of the cable through. Cut the cable and rejoin the ends along with the light fixture leads with waterproof wire connectors.
Step 4
Fasten the back plate
Push the wires back through the hole and screw the back plate to the planter siding.
Step 5
Mount the cover
Install the cover plate and tighten the set screws. Staple the wires somewhere on the backside to anchor them.
Step 6
Bore a 1-in. hole
To begin installing low voltage deck post lights, first bore a 1-in. hole down the center of the rail post. Drill deep enough to get below the second horizontal rail.
Step 7
Drill an intercept hole
Next, drill a 1/2-in. hole from below the rail. Angle up to intercept the 1-in. hole you just bored.
Step 8
Feed in the cable
Feed a heavy wire or electrician’s fish tape through the holes in the post. Tape the circuit cable to the wire and pull it back through the holes. Connect the cable to the post cap light’s feed wires with twist connectors.
Step 9
Install the post assembly
Screw the post-light assembly to the rail. Use four corrosion-resistant wood screws, one near each corner.
Step 10
New technique for low voltage deck post lights
For the new low voltage deck post lights, cut them in half lengthwise with a circular saw, then cut a groove for the wire and reglue the halves together with urethane glue. Feed the circuit wires through the post before connecting the fixture. Connect them to the fixture wires with the wire connectors and push the wire back into the post. Screw the post light to the top of the post.
Dig a hole 18 to 24 in. deep with a posthole digger to set the post. Adjust the length of the post to the hole’s depth, and drop the post into the hole. Partially fill the hole with dirt, plumb the post with a carpenter’s level and tamp the dirt around the post. Continue adding dirt, checking for plumb and tamping until the hole is completely filled. Cover the circuit wires with 6 in. of dirt.
Step 11
Rope light connections
Rope lighting is unique. It’s a flexible, solid plastic rod with a series of tiny bulbs embedded in it. Calculate the total length needed, add 10 percent and buy one long piece (it’s available in 250-ft. rolls) and cut it on the job.
Attach a power connector to one end of the rope lighting. The cord on the power connector then attaches to the circuit wire with twist connectors. You can connect multiple pieces of rope light with straight and 90-degree connectors, but it’s quite flexible and we were able to bend it around 90-degree corners without the 90-degree connector.
Step 12
Insert the contact pins
Connect the power cord to the end of the rope light by inserting the contact pins with pliers. Then assemble the rest of the connector.
Step 13
Mount the track
While you can install the rope with clips that mount every foot or so, the best system is a plastic rope light track. Cut the track to length and then mount it with nails or screws. We found that pre-drilling the back of the track and fastening with 3/4-in. corrosion-resistant screws worked best. Space the screws 2 ft. apart. Fasten the track within 3 in. of its ends.
Step 14
Cut the rope light
Round up a helper and stretch the rope light along the installed track, then cut it to length at one of the cutting marks.
Step 15
Mount the rope light
Push the rope light into the channel. A hammer handle or a piece of wood works well as a push tool and is easier on the fingers. Slide on an end cap.
Step 16
Stake the flood lights
Flood lights provide a wash that highlights features. Be careful not to direct the light into people’s eyes when they’re on the deck. Some flood lights come with a hood to reduce glare. A ground stake attached to the bottom of the fixture makes installation a snap. Bury the wire 6 in. deep.
Step 17
Additional Information
Figure A: Low-voltage deck lighting plan
Mark the light fixture locations on your deck plan. Locate the transformer next to an electrical receptacle; if necessary, add one. Draw routing lines for the wiring circuits. For our deck, the post lights, shown in green, highlight the main entrance to the house and light the path to the driveway. The step lights, shown in blue, add safety by lighting stairways. The rope lights, shown in red, highlight the planter boxes and add ambient light. The floodlights, shown in orange, highlight the plants and add to the look from the street.
Sizing the Transformer and Cables
Add the wattage of each fixture to determine the total load. Our deck:
| 4 step lights x 12 watts | 48 watts |
| 3 post lights x 20 watts | 60 watts |
| 60 ft. of rope light x 5.45 watts per ft. | 327 watts |
| 2 floodlights x 20 watts | 40 watts |
| Total | 475 watts |
| Add 25 percent excess: | |
| 475 x 1.25 | 594 watts (Transformer size: at least: 594 watts) |
Optional transformer features:
- Timer switch, which automatically turns the lights on and off at preset times.
- Photo eye, which turns the lights on at dusk and off at dawn.
- Individually switched circuits, which allow different groups of lights (scenes) to be independently controlled.
Size Circuit Cables
This allows for connecting fixtures with a maximum total of 150 watts.
| Length of Cable | Wire Size |
| 0 to 50 ft. | 12-gauge |
| 50 to 100 ft. | Use 10-gauge |
| 100-plus ft. | Use 8-gauge |
Step 18
FAQ
Can I connect my deck lighting to a timer or smart home system?
Yes, many low-voltage transformers come with a timer switch, which automatically turns the lights on and off at preset times. The other option is to use Wi-Fi bulbs in your deck lighting. Wi-Fi smart lights require no additional hardware; they use your existing router to connect to the internet. You can control when the lights go on and off, and even the color, through an app on your phone.
Does deck lighting require maintenance?
Yes, like anything that lives outdoors, your outdoor light fixtures get dirty. Turn the lights off, then wipe away dust and grime with a damp, microfiber cloth. Inspect lights regularly to check for bulbs that need to be replaced. Tighten loose screws and secure connections if you notice any flickering.
