Adding an outdoor outlet to an existing circuit can provide a convenient power source for patio lights, garden tools, holiday decorations and more. With some basic electrical knowledge and the right materials, this project can be completed safely by most DIYers.
Gather Necessary Materials
Before getting started, make sure you have all the necessary materials on hand:
- Exterior outlet box with cover – Ensure it is rated for wet locations
- Weatherproof GFCI outlet
- Outdoor-rated NM-B wire or UF-B cable
- Wire nuts
- Electrical tape
- Voltage tester
- Flat head screwdriver
- Phillips head screwdriver
- Wire strippers
- Drill and paddle bit (if installing new box)
Optional: Weatherproof outdoor box cover, junction box, electrical conduit
Turn Off Power
Safety should always be the number one priority when working with electricity. Before doing any work, locate the correct circuit breaker in the main service panel and turn it off. Verify power is off by using a non-contact voltage tester.
Tip: Write down which breaker controls the outlet circuit so you can easily turn power back on when the project is complete.
Choose Location
Decide where you want to add the new outdoor outlet. For most homeowners, placing it near an entryway, patio or balcony is ideal. Keep the following in mind:
- The box must be weatherproof and meet code requirements for wet locations if not under an overhang.
- Allow slack in the wire so the outlet can be pulled out for use. Don’t pull wires tight.
- For garages, outlets need to be located at least 18 inches off the floor per NEC code.
Feed the Wire
Run the new wiring from the chosen outdoor location back to the inside outlet you want to connect to. Here are two options:
Option 1: Through the Wall
If you have easy access behind the interior wall:
- Turn off power at the breaker.
- Cut a hole in the drywall behind the existing interior outlet.
- Feed the new NM-B wire from the outside, through the hole, to the interior outlet box.
- Secure the cable with cable clamps.
This method allows you to hide the wiring inside the wall. Patch and refinish the drywall when done.
Option 2: Through the Attic
If the outlet location does not align well for through-the-wall wiring:
- Locate the bay in the attic above the interior outlet.
- Drill a hole up through the interior outlet box.
- Push the cable up from the outside outlet location, through the hole into the attic bay.
- Pull the cable through to the interior outlet box.
This keeps wiring out of the living space. Seal up any holes with insulation when complete.
Connect the Wires
With the outlet boxes linked together, now you can make the electrical connections.
- Strip away 3/4 inch of outer insulation from the NM cable using wire strippers.
- Inside the interior box, use a wire nut to connect the black (hot) wire from the new cable to the hot wire on the existing outlet.
- Connect the white (neutral) wire from the new cable to the neutral on the existing outlet.
- Connect the ground wire from the new cable to the ground on the existing outlet.
- Wrap connections with electrical tape for extra protection.
- Follow the same process to connect the new wires to the new, exterior outlet.
Tip: Have at least 6 inches of extra wire in each box to make connections.
Install the Exterior Outlet Box
If the exterior wall surface is uneven, install a new weatherproof box:
- Trace the outline of the box on the wall.
- Drill holes at the corners and cut out the opening using a drywall saw.
- Place the box in the opening and secure with screws through the interior flanges.
- Caulk around the exterior edges for water seal.
- Secure the outlet and cover plate.
For flat walls, a simple weatherproof cover can be used over an existing electrical box.
Connect to a GFCI Outlet
Per code, outdoor outlets must be connected to GFCI (ground fault circuit interrupter) outlets for safety. This can be done in one of two ways:
At the Interior Box
Replace the standard interior receptacle with a GFCI outlet. Connect the new outdoor outlet wires to the LOAD terminals. This provides GFCI protection for the entire circuit.
At the Exterior Box
Use a weatherproof GFCI outlet for the exterior box only. Connect the new wires directly to the outlet. The indoor outlet will still need GFCI protection if near water sources.
Complete the Project
You’re almost done! Follow these final steps to finish off the new outdoor outlet installation:
- Make sure all wire connections are secure and tucked neatly into boxes.
- Attach weatherproof covers to both boxes.
- Caulk around exterior box edges for moisture seal.
- Label the new circuit at the electrical panel.
- Restore power and test that the new outlet works.
- Use a GFCI tester to verify protection on the outlet.
That’s it! Now you have a safe, code-compliant outdoor outlet ready for use.
Outlet Installation Tips
Follow these tips for the best results on your new outdoor outlet installation:
- Use rugged, weatherproof boxes and covers made for outdoor use. Look for the “WR” water-resistant rating.
- Only use wiring approved for outdoor, wet locations like UF-B underground feeder cable or outdoor-rated NM-B wire.
- Avoid voltage drop by using #12 AWG wire for outlet runs up to 100 ft from the panel. Go thicker for longer distances.
- Use in-box GFCI outlets for easiest installation. In-line GFCIs can also be used but may require an additional box.
- Replace standard interior outlets connecting an outdoor circuit with GFCI outlets for complete protection.
- Caulk thoroughly around exterior box to prevent moisture contact with wiring.
- Consider placing new outlet box inside a covered patio or balcony area whenever possible. This provides shelter and easier access.
- Shut off power and test GFCI outlets monthly by pressing the TEST and RESET buttons.
Outdoor Outlet Location Ideas
Some creative ideas for handy outdoor outlet locations include:
- By exterior doors for plugging in holiday lights and decorations.
- On porches, patios or balconies for lamps, bug zappers, fans.
- Near garage or shed entrances for powering tools and equipment.
- By garden areas for irrigation controllers, lighting, or DIY projects.
- Front walkways and driveways for holiday or event lighting.
- Backyards and decks for parties, string lights, inflatables.
- Near pools, hot tubs, or outdoor kitchens for convenient appliance use.
- End of docks or by boat lifts to power pumps or electric watercraft.
Strategically placing outdoor outlets allows easy access where you need it most for all your exterior lighting, appliance and entertaining needs.
Safety Tips for Outdoor Outlets
When installing and using outdoor receptacles, keep these safety guidelines in mind:
- Always turn off power at the breaker before doing any electrical work. Double check it’s off.
- Only work on wires when they are 100% de-energized for your safety.
- Choose outdoor-rated wiring designed for wet, exposed locations. Never use indoor-only NM cable outside.
- Use GFCI outlet protection on all receptacles installed in exterior, damp locations.
- Install weatherproof covers and boxes rated for outdoor use. NEMA 3R or better is ideal.
- Caulk thoroughly around the outlet box to prevent water intrusion into wires.
- Use ground fault protection on any circuits running near pools or hot tubs as required.
- Shut power off to outdoor outlets before pressure washing siding or using extension cords in the rain.
- Never touch outlets or wiring with wet hands.
- Have a qualified electrician handle any aspects you are unsure of.
FAQs About Adding an Outdoor Outlet
Some common questions that arise when adding an outdoor outlet:
How much does it cost to add an outdoor outlet?
The cost to add an outdoor outlet averages $150-$250 in materials and labor. DIY installation reduces costs to under $100 for parts.
Can I tap into an existing outdoor outlet?
Yes, you can connect multiple outdoor outlets in sequence on the same circuit. Use adequate gauge wiring and watch voltage drop.
Do outdoor outlets need to be GFCI?
NEC code requires GFCI protection on all outdoor outlets installed in damp, wet or exposed locations.
Can I install an outdoor outlet myself?
Most DIYers are able to safely install outdoor outlets. Follow code and use extreme caution when working with wiring.
How deep should an outdoor outlet box be mounted?
Outdoor boxes must be mounted with at least the front face flush with the siding. Any more than 1/4″ recessed requires an extension cover.
Can I use indoor wire for an outdoor outlet?
No. Outdoor wiring like UF-B and NM-B wire is specially designed for wet locations. Romex and other indoor-only wire can short out.
Do I need a permit to add an outdoor outlet?
Permits are not typically needed for minor outdoor outlet additions. But always check with your local permitting office to be sure.
Can outdoor outlets be linked to smart home devices?
Yes! Outdoor outlets can absolutely be incorporated into smart home systems using smart plugs or wirelessly controlled outlets.
Conclusion
Adding an outdoor outlet is a convenient DIY project that can provide power where you need it most outside your home. By following basic electrical safety precautions, using the proper outdoor-rated materials, and tying into an existing indoor circuit, you can create a safe, code-compliant exterior receptacle. Pay special attention to sealing boxes and covers from moisture and incorporating GFCI outlets. With attention to detail, you’ll have a professional new outdoor outlet to use for years to come.
So in summary:
- Turn off power and use safe practices when working with electrical.
- Choose an outdoor box location that’s accessible but protected from weather.
- Run wiring from the new outlet to an existing indoor circuit.
- Use the proper outdoor-rated wiring and connections.
- Install a weatherproof exterior box and GFCI outlet.
- Follow code requirements for outdoor outlets, like GFCI protection.
- Use caulk and covers to prevent moisture contact with outlet wiring.