Installing an outdoor outlet box allows you to power outdoor lighting, appliances, tools and more. Having an outdoor receptacle makes outdoor living easier and more convenient. With the right materials and safety precautions, installing an outdoor outlet box is a manageable DIY project.
Materials Needed
Before starting this project, make sure you have all the necessary materials:
- Outdoor outlet box with cover – Choose a weatherproof box rated for outdoor use. A plastic or fiberglass box works well. Make sure it has a cover to keep out moisture.
- GFCI outlet – Outdoor outlets must be GFCI protected for safety. Choose an outdoor-rated, weather-resistant GFCI outlet.
- Outdoor-rated cable – Use 12/2 or 12/3 cable rated for outdoor and underground use. It should be clearly labeled as sunlight and water resistant.
- Wire connectors – Get twist-on wire connectors rated for outdoor use. They will resist corrosion better than indoor connectors.
- Conduit – Use rigid metal or PVC conduit to protect the wiring running to the outlet box.
- Fasteners – Get weatherproof screws, nails or other fasteners for securing the outlet box and conduit. Outdoor-rated adhesives work too.
- Circuit breaker – Have a dedicated 15 or 20 amp circuit breaker for the outdoor outlet.
- Wire strippers, cutters, drill, hammer, level, tape measure and other basic tools.
- Personal protective equipment – Wear safety goggles, work gloves and appropriate work clothes when installing the outlet.
Before starting, make sure to:
- Turn off the main power at the breaker box.
- Test wires with a voltage tester to be sure they are dead.
- Review electrical codes for your area and get any necessary permits.
Choosing an Outdoor Location
Pick an outdoor spot for the outlet that is:
- Close enough to power tools, lighting or appliances.
- Protected from severe weather as much as possible.
- Not in a low spot where water collects.
- Not directly under roof overhangs where moisture drips.
Consider placing it:
- On a covered porch or patio.
- Under an eve or overhang on the house or garage.
- On a post or side wall of the garage, shed or workshop.
Avoid putting it somewhere it will be directly exposed to heavy rain, snow, mist or lawn sprinklers.
Place it at least 12 inches off the ground to avoid lawn mower damage, ground moisture and flooding.
Make sure the location allows wires to be run neatly and safely from the indoor panel.
Installing the Outdoor Box
Follow these steps to install the outdoor receptacle box:
Step 1: Turn Off Power
Before installation, turn off power at the main breaker panel. Use a non-contact voltage tester to confirm power is off to the outlet location before working.
Step 2: Cut Power Cable to Length
Run cable from the indoor panel to the outlet box location. Leave plenty of extra length for adjustments. Cut the power cable to the needed length using cable cutters.
Step 3: Strip the Wires
Strip away 3/4 inch of the outer plastic sheathing from the end of the cable using a wire stripper tool or utility knife.
Be careful not to nick the inner wires. Strip 3/8 inches of insulation from the ends of the black, white and ground wires.
Step 4: Install Conduit
Run plastic or metal conduit from the power source to the outlet box. Conduit protects the wiring. Use waterproof fittings and connections when joining conduit pieces.
Step 5: Mount the Outdoor Box
Hold the outlet box against the mounting surface and mark the spots for screws or anchors. Drill guide holes if needed.
Use outdoor-rated screws or waterproof adhesive to mount the box securely. Make sure it is plumb and level.
Step 6: Thread Cable Through Conduit
Thread the end of the cable through the conduit from the power source to the outlet box. Pull steadily to move it through the conduit until it comes out at the box.
Step 7: Connect Wires to the GFCI Outlet
Strip 3/8 inches of insulation from the wire ends. Connect the black (hot) wire to the brass screw, white (neutral) wire to the silver screw, and ground wire to the green screw on the GFCI outlet using wire connectors.
Step 8: Secure the GFCI in the Box
Once wired securely, push any excess wire back into the box to reduce clutter. Secure the GFCI outlet in the outdoor box using the included screws.
Step 9: Attach the Cover
Attach a weatherproof cover and seal it according to the manufacturer’s directions. This protects the outlet from moisture.
Step 10: Turn Power Back On
Head back inside and turn the power back on at the breaker box. Go outside and test the outlet. Press the “Test” and “Reset” buttons on the GFCI to confirm it works.
Installing and wiring an outdoor outlet is now complete. Keep reading for more tips on using and maintaining it.
Operating an Outdoor Outlet Safely
Take the following precautions when using your new outdoor receptacle:
- Always plug outdoor appliances and tools into a GFCI-protected outdoor outlet. This will shut off power if a problem occurs.
- Inspect the outlet frequently for signs of damage, cracks or corrosion. Call an electrician if you see any issues.
- Use a plastic weatherproof cover that completely seals the outlet from moisture. Replace it if cracked or damaged.
- Consider using a plastic bag or commercial outlet cover to keep the outlet extra dry when not in use.
- Avoid using electrical appliances outdoors in wet conditions or while standing in water.
- Exercise caution when using long extension cords. Don’t let cords cross walking areas or dangle where they can get damaged.
- Check that all outdoor power tools and appliances are rated for outdoor use and grounded properly.
- Always power outdoor lighting and decor through a GFCI outlet for protection.
- Hire an electrician if you experience tripped GFCI outlets, flickering lights, tingling from the outlet or other electrical issues.
Tips for Maintaining an Outdoor Outlet
Regular maintenance keeps your outdoor outlet working safely and reliably:
- Inspect it periodically for damage, dirt, moisture or insects. Clean out any debris.
- Spray with electrical contact cleaner or wipe down with isopropyl alcohol to clean corrosion and improve electrical connections.
- Clear dirt, grass, leaves or other matter away from the box and conduit openings.
- Check that all covers, conduit and the box are sealed to keep moisture out. Reseal if needed.
- Make sure the mounting screws are tight and connections are secure.
- Test the GFCI outlet by pressing “Test” then “Reset” buttons. Replace GFCIs that fail to trip and reset properly.
- Check that GFCI outlets are rated for “weather resistant” use if exposed to the elements.
- In harsh climates, install extra weatherproof outlet covers when the outlet is not in use.
- Rewire, upgrade or relocate the outdoor outlet if it gets damaged or worn out.
With proper installation, safe operation and maintenance, your outdoor outlet will serve you reliably for years to come. Call an electrician if you have any concerns about electrical safety, performance or repairs.
Wiring an Outdoor Outlet from an Indoor GFCI
Outdoor outlets should be wired through a GFCI outlet indoors for added protection. Here are the steps:
Step 1: Turn Off Power
Switch off electricity at the main breaker panel before wiring the outlet.
Step 2: Install Indoor GFCI Outlet
Replace an indoor receptacle along the circuit you are using with a GFCI outlet. Follow typical wiring procedures.
Step 3: Run Cable to Outdoor Box
Run 12/2 outdoor-rated power cable from the indoor GFCI to the outdoor box location. Run it through conduit for protection.
Step 4: Splice to Extend the Circuit
Inside the outdoor box, use waterproof wire connectors to splice the new cable wires to the wires running from the indoor GFCI:
- Black cable wire to black wire
- White cable wire to white wire
- Grounds connected together
This extends the indoor GFCI-protected circuit to the outdoor box.
Step 5: Connect Wires to Outlet
Connect the black, white and ground wires to the outlet as usual. Follow the wiring diagram on the back.
Step 6: Mount Outlet in Box
Attach the wired outlet securely in the outdoor box. Install covers and seals.
The outdoor outlet is now powered safely through the indoor GFCI. Test that the GFCI provides expected protection.
Frequently Asked Questions
How deep should the outdoor box be mounted?
Mount the outlet box so the front face will sit about 1/2 inch back from the finished outdoor wall surface. This allows room for the outlet and cover to fit.
Can I use the same neutral for two outdoor circuits?
No, you should not share a neutral between two branch circuits. Each 120V circuit needs its own dedicated neutral wire.
Is conduit required for outdoor outlets?
Outdoor electrical conduit is required by code for any wiring that is not going to be buried underground. It protects against damage.
How do I weatherproof an outdoor outlet?
Use weatherproof boxes and covers, conduit, caulk all holes, seal openings with silicone, use GFIC outlets, and keep connections tight.
What size wire is needed for an outdoor outlet?
For a standard 15 or 20 amp outdoor receptacle circuit, use 12 AWG or larger copper wire rated for outdoor use.
Can I install low voltage lighting on the same transformer as an outlet?
No. Low voltage lighting should have its own separate transformer that is not associated with the high voltage outlets.
How many outlets can I have on one 20 amp outdoor circuit?
10 to 12 15 or 20 amp outlets is a common configuration for a 20 amp outdoor lighting circuit. Space outlets evenly around the circuit.
Is a neutral required for an outdoor light switch?
Most outdoor light switches do not require a neutral connection. However, some smart switches and timers may need a neutral wire.
Can I bury Romex underground?
No. Romex or NM cable should never be run underground or embedded in concrete. Use wiring approved for direct burial.
How do I control moisture in an outdoor box?
Use plastic or fiberglass box rated for wet locations, mount vertically, seal openings with silicone caulk, use foam gaskets behind covers, and close unused knockouts.
Conclusion
Installing an outdoor outlet is essential for powering patio lighting, appliances, holiday decorations and yard tools. With the right waterproof boxes and wiring, it can be a DIY project for a homeowner comfortable working with household electrical.
Always exercise extreme caution when working with any electrical systems. Follow local building codes and permit requirements. If unsure about any wiring procedures, hire a professional electrician service. They can ensure proper installation that will pass inspection and provide peace of mind about electrical safety.
A properly installed GFCI-protected outdoor receptacle will offer many years of trouble-free performance and convenience for your home. With regular inspection and maintenance, your outdoor outlet will enhance your living space and provide power where you need it outside.