How to Install Deck Post Cap Lights

1) Router a 3/4" deep channel into the 2x4 top rails. This will allow you to hide the low-voltage wire under the top cap. Also router a 3/4" channel down the side of the rail post, closest to the transformer. This will allow you to transfer the wire from under the deck to the top rail. Place the transformer next to the electrical outlet.
2) Drill a hole into the center of the top of your rail posts using a 2" forstner bit. Drill a 1/2" hole from the side of the top rail through the center hole to pull the low-voltage wire through.
3) Run the wire from the transformer to the first light, leaving a 6" loop of wire at the top of the post. Continue the process of threading the wire along the rail through each post, leaving a loop of extra wire at each post. Do not secure the top cap until the lighting system is finished and working.
4) At each post, cut the wire and separate the wires into 2-3" strands. Use a wire stripper to remove about 1/2" of sheathing from each wire and the wires from the light cap.
5) Match the polarity of the wires. One wire will have a smooth black wire and the other will have white lettering or ribbing. Hold the wire ends together and connect them by twisting waterproof wire nuts to create a tight connection. Wrap the connection with electrical tape.
6) Read the instructions for your transformer. Make sure the on/off switch is turned off. Secure the transformer using mounting brackets to its desired location and run the wires into place and connect. Make sure the photo eye sensor is accessible to sunlight.
7) Plug the transformer into the outlet and turn it on. Test the lighting and set the timer as needed.
8) Unplug the transformer and secure the top cap to hide the low-voltage wire. Be careful not to screw into the wire.
Installing Side Mount Deck Lights
1) Router a 3/4" deep channel into the 2x4 top rails. This will allow you to hide the low-voltage wire under the top cap. Also router a 3/4" channel down the side of the rail post closest to the transformer. This will allow you to transfer the wire from under the deck to the top rail. Place the transformer next to the electrical outlet.
2) Drill a hole into the center of the top of your rail posts using a 2" forstner bit. Drill a 1/2" hole from the side of the top rail through the center hole to pull the low-voltage wire through. Determine the height of the side-mounted lights. This is usually just below the top rail. Drill a 1/2" hole from this location into the center post hole.
3) Run the wire from the transformer to the first light, leaving a 6" loop of wire at the top of the post. Continue the process of threading the wire along the rail through each post, leaving a loop of extra wire at each post. Do not secure the top cap until the lighting system is finished and working.
4) At each post, cut the wire and separate the wires into 2-3" strands. Use a wire stripper to remove about 1/2" of sheathing from each wire and the wires from the light cap.
5) Match the polarity of the wires. One wire will have a smooth black wire and the other will have white lettering and ribbing. Hold the wire ends together and connect them by twisting waterproof wire nuts to create a tight connection. Wrap the connection with electrical tape.
6) Read the instructions for your transformer. Make sure the on/off switch is turned off. Secure the transformer using mounting brackets to its desired location and run the wires into place and connect. Make sure the photo eye sensor is accessible to sunlight.
7) Plug the transformer into the outlet and turn it on. Test the lighting and set the timer as needed.
8) Unplug the transformer and secure the top cap to hide the low-voltage wire. Be careful not to screw into the wire.
Deck Skirting
Skirting can be an attractive feature that can be added to any low-level deck.
Building an Outdoor Kitchen? Here’s What You Should Consider Before You Start
Building an outdoor kitchen is an investment that can add value to your home. Learn what you should consider before building an outdoor kitchen on Decks.com.
Outdoor Water Features to Enhance Your Space
Looking to add a water feature to your backyard or patio? Check out our top ideas to add some tranquility to your outdoor space.
Decking Patterns
Step into the world of deck design and push the limits of your imagination with our collection of deck patterns and ideas. From classic single-width and diagonal layouts to intricate herringbone and chevron designs, we illustrate the wide range of patterns that will unlock your creativity.
Zipper or Hearing Bone Decking
Learn how to install a herringbone zigzag decking design by installing blocking to the deck frame.
From Swim to Sun: 5 Tips for Building a Deck Around Your In-Ground Pool
The pool-deck combo is the perfect outdoor layout for a relaxing, warm-weather hang. Check out these tips on how to design your space.
More Helpful Resources
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights
5 Best Ways on How to Hide Trash Cans Outside
Outdoor trash cans can be an unwanted eyesore. Discover how you can easily cover them up and add an extra touch of beauty to your yard.
Underrated + Overlooked Features to Consider Adding to Your Deck
Want to give your deck or patio a unique look? These creative deck ideas will upgrade your deck in no time.
How To Install Deck Lighting
Step-by-step instructions on how to install low-voltage post cap lights. Learn about cutting a groove to hide your wiring.
Pool Deck Ideas on a Budget
A stylish poolside retreat doesn't have to come with an over-the-top price tag. Allow us to show you some easy and innovative ways to build a stunning pool deck that won't empty your wallet.
The Ultimate Guide to Mood Lighting for Your Outdoor Space
Light up your outdoor space with effective mood lighting. Our guide covers everything from installation tips to choosing the best lights for a cozy, inviting atmosphere on your deck.
From Swim to Sun: 5 Tips for Building a Deck Around Your In-Ground Pool
The pool-deck combo is the perfect outdoor layout for a relaxing, warm-weather hang. Check out these tips on how to design your space.
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights