How to Install an Outdoor Light Fixture Box - Outdoor Cabinets

Introduction

Installing an outdoor light fixture box allows you to mount outdoor lighting on your home. With the right light fixture box, you can easily install path lights, spotlights, or other exterior lighting to illuminate walkways, accent landscaping features, or provide security around your home’s perimeter. Installing a light fixture box is a relatively straightforward do-it-yourself project for most homeowners.

In this comprehensive guide, we will walk through all the steps involved in how to install an outdoor light fixture box correctly. We will cover choosing the right type of box, selecting the ideal location, installing the electrical wiring, attaching the box securely, and adding the finishing touches for a professional look. With the help of this guide, you will have the confidence to install a robust and safe outdoor light fixture box to showcase your home’s exterior.

How to Choose the Right Outdoor Light Fixture Box

When installing an outdoor light fixture, the first step is selecting the proper electrical box to mount the light fixture securely. There are several factors to consider when choosing an outdoor light box:

Type of Mounting

Wall Mount – For mounting flush to the wall. Requires cutting a hole in the wall cladding to recess the box. Best for spotlights or path lighting mounted to the house exterior.
Eave Mount – For under-eave installation on the roof overhang. Mounts to the fascia or rafter tails. Perfect for accenting architectural features.
Pole Mount – For mounting on top of a pole embedded in the ground. Ideal for path lights or perimeter spotlights to illuminate gardens and landscaping.
Ground Mount – For permanent in-ground installation. Requires digging a hole for installation. Used for accent lights focused on landscaping.

Material

Plastic – Economical option suitable for protected areas. Not as durable for wet locations.
Metal – More expensive but extremely durable. Withstands moisture and resists corrosion. The best choice for wet areas.
Cast Aluminum – Very durable but higher cost. Provides excellent protection in all weather.

Electrical Format

Low Voltage – For 12V or 24V landscape lighting systems. Two-wire connection. Safest for DIY installation.
120V AC – Standard 120-volt household power. Requires proper outdoor-rated 120V fixtures. Higher wattage available.

Weather Protection

Weatherproof – Seals out moisture. Required for wet locations and outdoor installation. Gasketed cover protects connections.
Weather Resistant – Some protection from moisture but not fully sealed. Only for protected dry locations.

Box Format

Single Gang – Standard size for one fixture. Up to two ports for low voltage or one 120V fixture.
Double Gang – Larger size for multiple fixtures. Up to four low voltage or two 120V fixtures.
Round Box – Cylindrical style. Available in single, double, or triple fixture format.

Specialty Options

Photocell – Turns light on at dusk and off at dawn automatically. No wiring to switches needed.
Timer – Schedules lights to turn on/off on a preset schedule. Easier than using an external timer.
Motion Sensor – Detects movement and turns light on when activity is sensed. Turns off after a delay when no motion detected.

How to Select the Ideal Location

Choosing the right location is critical for proper light distribution when installing an outdoor light fixture box. Here are some tips on selecting the ideal mounting spot:

For path lighting, space boxes evenly along the path at desired intervals. Place them approximately 10-15 feet apart.
For spotlighting architectural elements, position the box where the beam will highlight the desired area. Focus on lighting the feature, not just the general area.
For accent lighting landscaping, choose a location that will focus the light on the specific plant or tree intended to accentuate.
For general area lighting, determine the darkest spots that would benefit from better illumination. Spacing boxes 25-30 feet apart will provide broader light coverage.
For security lighting, mount boxes at vulnerable points of entry where light will deter intruders. Near doors and gates and where shadows could conceal prowlers.
Avoid aiming fixtures directly into neighboring windows, passersby eyes, or drivers line of sight where glare could be intrusive. Angle lights thoughtfully.
Place boxes 4 to 5 feet above the ground for best light spread from most fixtures. Higher for targeting second story features.
Check for obstructions like tree branches or roof overhangs that could block the light when choosing your location.

Also consider the following when deciding on the mounting spot:

Proximity to an electrical source. Evaluate wiring needs.
Accessibility for installing the box and running wires.
Visibility of the box. If aesthetics are a concern, conceal in shrubs, under eaves or use a recessed wall mount.

With good placement planning, your outdoor light fixtures will maximize visibility and dramatically accent the beautiful features of your home and landscape.

How to Install Electrical Wiring for an Outdoor Light

One of the most important steps in installing an exterior light fixture box is properly running electrical wiring to power the light. Here is a step-by-step guide for wiring an outdoor light box safely:

Step 1: Turn Off the Power

The first and most crucial step is to shut off power to the circuit you will be working on. Locate the appropriate circuit breaker or fuse powering the area and switch it to the OFF position. Use a contact voltage tester to confirm power is off before proceeding.

Step 2: Run Wire from Power Source

Next, you will run wiring from the power source to the light fixture box location. Here are two options:

Using Existing Wiring – If you already have wiring routed to the desired location, you can tap into this line with proper wire nuts/connectors. Be sure to only tap the line in a junction box, not exposed wires.
Running New Wiring – For new wiring, you will need to route a 2 or 3 wire 120V line (hot, neutral and sometimes ground) from the breaker to the new box location. Use proper burial-rated outdoor wire. Avoid surface wiring without conduit. Bury wires at least 6 inches or according to local electrical code.

Step 3: Leave Extra Length

When running your wires, ensure you leave at least 6 to 12 inches of extra wire extending past the end of the electrical box. This will allow slack for connecting the wires within the box.

Step 4: Weatherproof Box Connections

Once connected to power, carefully tuck the wires into the electrical box, ensuring wire nuts/connections stay sealed within the box, not exposed. Attach a weatherproof cover and gasket to seal out moisture. Caulk conduit openings if using.

Step 5: Attach Ground Wire

If your box requires a ground wire, attach this to the green grounding screw inside the box or ground port. Ensure ground wires are properly connected for safety.

Step 6: Test Circuit

With all wires securely connected, restore power and test the circuit with a voltmeter or by temporarily attaching a light. Verify proper operation before finishing the installation.

How to Install and Mount the Outdoor Light Box

Once the electrical wiring is in place, you can move on to securely mounting the outdoor light fixture box. Proper installation is key to keeping electrical connections protected from the elements.

Step 1: Turn Off Power Again

Before working on the box, switch off power again at the breaker/fuse to avoid shock hazard while handling wires.

Step 2: Position the Box

Hold the electrical box in the desired mounting location. Use a level to ensure it is straight. Mark spot where the mounting screw holes will go.

Step 3: Drill Entry Holes (If Necessary)

For mounting on walls, drill entry holes for electrical conduit leading to the box. Hole should align with the conduit knockout openings on box.

Step 4: Mount the Box

Secure the box in place using appropriate screws for the material. Wall boxes should use proper wall anchors. Be sure box is firmly anchored.

Step 5: Seal Box

Caulk around edges of wall-mounted boxes with exterior silicone caulk. For recessed boxes, use foam gasket pads under the lip to seal. This prevents moisture getting behind box.

Step 6: Make Wire Connections

Thread wires from light fixture through knockout hole into box. Use wire nuts to connect matching hot, neutral and ground wires.

Step 7: Tuck Wires Carefully

Ensure wires are neatly tucked into box with connections sealed inside. Attach weatherproof box cover tightly.

Step 8: Test Lights

With box properly sealed. Turn power back on and test operation of light fixture before finishing exterior wall surface.

With the electrical box solidly attached in the ideal spot, you can now complete the installation by adding the exterior wall surface or siding material. For lights on the home, ensure the box is flush with the finished wall. Caulk gaps if needed when done.

Helpful Tips for a Professional Finish

Follow these additional tips when installing your outdoor light fixture box for clean, professional results:

For recessed wall boxes, cut the hole in wall material slightly larger than the box to prevent binding when installing siding.
When recessing metal boxes in masonry, chisel box edge depth into wall, then backfill around box with mortar to hold in place.
Use exterior-grade silicone caulk around all exterior box edges and conduit penetrations.
Consider installing a small gravel bed and drain hole underneath boxes mounted in the ground to prevent standing water inside the box.
For easier seasonal light storage, use winged box mounting screws. This allows removing fixture leaving screws in place.
Paint electrical boxes black or to match the fixture for a coordinated look. Use exterior enamel spray paint.
Keep all light fixture manuals and hardware together during installation for easy reference and final assembly.
Aim adjustments and testing fixture performance is easier before permanently attaching siding/trim around the box.
Ensure all outdoor-related codes are followed, including depth of underground wiring, burial methods, GFCI circuits near water, etc.

With attention to detail during installation and weather sealing, your outdoor light fixture boxes will keep electrical connections protected and functioning optimally for years of service.

Frequently Asked Questions about Installing Outdoor Light Boxes

Should I use a plastic or metal exterior light box?

For wet locations, a metal box is strongly recommended due to its durability and water resistance. Plastic is acceptable for protected areas but is more prone to moisture damage over time. Cast aluminum boxes offer the best protection.

How deep should I bury the wiring underground?

Low voltage landscape lighting wire should be buried at least 6 inches. For 120V AC wiring to light boxes, bury at a minimum of 12 inches below grade according to electrical code. Deeper burial offers more protection.

Can I tap into existing outdoor wiring for a light fixture?

Yes, you can tap into existing outdoor wiring in a junction box using proper waterproof connections and wire nuts. Never tap into exposed wiring outside of an enclosed junction box.

How do I determine the box size needed for the light fixture?

Check your light fixture requirements for wattage and number of bulbs to determine electrical load. Compare this to the capacities of various box sizes to choose the one able to handle the load.

Should I caulk around the mounting box?

Yes, sealing the edges with silicone caulk is highly recommended for moisture protection on outdoor boxes, especially in wet climates. But take care not to get caulk inside box.

Do I need a junction box for low voltage landscape lighting?

No, you typically do not need a junction box for low voltage landscape lighting circuits. The wires are safe to connect using waterproof direct burial connectors.

Can I reuse an existing exterior light fixture box?

You may be able to reuse an existing exterior box if it is still in good condition without corrosion or damage, and if it is suitable for your new light fixture’s specifications.

How do I mount a light box on vinyl siding?

Use a specialized vinyl siding mounting bracket that spaces the box off the wall slightly allowing room for the siding to expand and contract. Attach to solid structure, not just siding.

How far apart should I space landscape path lights?

For general landscape path lighting, spacing the path light boxes 10 to 15 feet apart will provide nice, even illumination along the walkway. Adjust spacing as needed for desired light levels.

Conclusion

Installing an outdoor light fixture box allows you to easily mount path lighting, spotlights, or other exterior illumination perfectly positioned to enhance your home’s landscape and architecture. We have covered the key steps including selecting the ideal outdoor-rated box, running protective wiring, securely mounting the box, and finishing the installation like a professional.

With the techniques outlined in this guide, you can confidently install robust outdoor light boxes that will keep your home and property beautifully illuminated for many years of enjoyment and added security.