Wiring an outdoor light means using weather-rated parts, a switch or GFCI circuit, and tight, code-compliant connections.
A tidy outdoor light adds security, visibility, and curb appeal. This guide lays out a clear plan, safe parts, and code cues so you can route cable, mount boxes, make solid splices, and test the result without guesswork. You’ll see what to buy, how to run the cable, and which rules keep the install dry and durable.
Quick Plan And Parts
Pick the path and the hardware before lifting a tool. Here’s the high-level flow most DIYers follow:
- Power source: breaker panel or an existing GFCI-protected outdoor box.
- Control: standard switch, smart switch, timer, or photocell.
- Cable: UF-B for direct burial or THWN-2 conductors in conduit.
- Boxes: exterior-rated, with gasketed covers and listed fittings.
- Connectors: weatherproof cable clamps and wet-location wirenuts.
- Fixture: marked “Wet Location” when exposed to rain.
- Grounding: bond metal boxes and the fixture strap.
Outdoor Light Wiring Options And When To Use
The table below helps you choose a method that matches your route, budget, and soil/wall conditions.
| Method | Best Use | Notes |
|---|---|---|
| UF-B Cable (Direct Burial) | Yard runs to a wall light or post | Simple trenching; protect from damage; common for small loads. |
| THWN-2 In PVC Conduit | Underground routes needing easy pulls or future upgrades | Great in corrosive soils; smooth pulls; individual conductors. |
| THWN-2 In EMT (Above Grade) | Exposed walls or garage runs | Rigid, neat bends; bond metallic raceway; use rain-tight fittings. |
| Surface UF-B (Guarded) | Short exterior hops under eaves | Allowed when not subject to damage; staple neatly and use clamps. |
| Smart Switch + Line Voltage | Porch or garage light with app control | Many smart switches need a neutral; confirm box fill and depth. |
| Low-Voltage Transformer | Path and landscape lighting | Plugs into GFCI receptacle; easy to expand; no trench to code depth. |
| Photocell Or Timer | Dusk-to-dawn or scheduled lighting | Wire per device diagram; often fits in the fixture box. |
How to Wire an Outdoor Light: Tools, Cables, Safety
Tools And Supplies
- Non-contact voltage tester and a plug-in GFCI tester
- Wire stripper, lineman’s pliers, screwdrivers
- Drill, driver bits, and a masonry bit for brick or block
- Fish tape, cable staples, exterior caulk, silicone
- Weatherproof box with gasket; in-use cover if adding a receptacle
- 14/2 or 12/2 UF-B or THWN-2 conductors with PVC/EMT conduit
- Wet-location wirenuts and listed bushings for sharp edges
Safety First
- Shut off the breaker. Place tape over the handle so no one flips it.
- Prove it’s dead with your tester at the switch and at the exterior box.
- Work dry. Wear eye protection. Choose a sturdy ladder and helper when needed.
Step-By-Step: From Source To Switch To Light
Step 1: Map The Route
Plan a simple path: panel → switch → light. Avoid circuits already loaded with heavy appliances. Keep cable runs straight, supported, and protected from nails or sharp edges. If tapping an exterior GFCI box, confirm there’s capacity and box fill for the added splices.
Step 2: Pick The Wiring Method
Two common choices get almost every job done:
- UF-B: fine for direct burial and certain surface runs that are not subject to damage.
- THWN-2 in conduit: durable in soil, tidy on walls, and easy to upgrade later.
Both approaches are recognized in code summaries used by the trade, including notes on cable listings and wet-location conductors. See a clear primer on NEC outdoor wiring methods and a quick comparison of UF-B vs THWN conductors for outdoor runs from industry sources. Those pieces echo what field pros do day-to-day.
Step 3: Mount The Exterior Box
Hold the box level under the eave or on a wall bracket. Caulk the top and sides; leave the bottom edge able to drain. Fasten to solid framing or anchors. If the fixture is heavy, use a listed brace. Set the foam or rubber gasket so it stays flat when you tighten the canopy.
Step 4: Run The Cable Or Conduit
Drill from the interior switch cavity to the exterior box. Add a bushing at every sharp edge. Inside, staple cable within reach of the box clamps per your local rules. Outdoors, trench neatly and avoid roots or sprinkler lines. Burial depth depends on method; code tables require more cover for direct-buried cable than for GFCI-protected conduit runs at a dwelling.
Step 5: Wire The Switch Loop
- Feed the incoming hot to the switch common (usually the darker screw).
- Send the switched hot to the light on a re-marked white or a red conductor.
- Tie neutrals together with a wirenut; a standard switch does not take neutral.
- Bond the ground to the metal box (if used) and the device yoke.
Smart switches often need a neutral. Plan conductor count and box volume before you close anything up.
Step 6: Make Weather-Tight Splices At The Light
- Connect white to white (neutral).
- Connect the switched hot to the fixture hot lead.
- Tie grounds together and land on the green screw of the strap.
Use wirenuts rated for wet locations and fold the conductors so the cover closes without strain.
Step 7: Add Optional Control
Photocells and timers keep a porch or driveway light on a schedule. Many devices tuck into the box or wire in-line. Follow the device diagram and color code. Smart fixtures or switches usually need a neutral and 2.4 GHz Wi-Fi.
Burial Depth And Wet-Location Ratings
Cover depth changes by method and location. A common residential setup is a 120-volt, 20-amp, GFCI-protected branch in PVC, which many jurisdictions allow at 12 inches of cover. Direct-buried UF often needs 24 inches. Under a driveway, use rigid metal or Schedule 80 PVC and go deeper per the table. The chart in Table 300.5 is the reference inspectors use; trade summaries mirror those numbers and add field notes on protection and risers.
Outdoor outlets at homes need GFCI protection under modern code updates, and that requirement extends to many outdoor service points. A plain-language explainer from a major manufacturer clarifies where GFCI now applies and how “outlet” includes more than receptacles. See NEC 210.8(F) outdoor outlet coverage. For general wiring design and protection basics that keep people safe, OSHA’s rule page outlines principles used on jobsites and in facility maintenance; the same habits help in home projects: OSHA 1910.304.
Switch And GFCI Pairing
If your source is a GFCI receptacle, land the feed on the LINE terminals and the light on LOAD so the light shares protection. Label the cover “GFCI Protected.” If trips appear after rain, check for water in the box, damaged insulation, or a shared neutral tied into a different circuit.
Grounding And Bonding
Ground every metal path. In a plastic box, tie all grounds together and add a pigtail to the strap. In a metal box, bond the box and the device. Use green screws or listed clips. Do not swap in drywall screws for bonding.
Testing And First Power-On
- Pull test each splice. Nothing should slip.
- Restore power; flip the switch. Confirm a steady light.
- Press the GFCI test; the light should go dark. Press reset to restore.
- Use your plug-in tester at any new receptacle tied to the same branch.
Troubleshooting Quick Hits
- Breaker trips instantly: hot touching neutral or ground; inspect for a nicked conductor.
- Light dead: open neutral, switch on the neutral by mistake, or a bad lamp/driver.
- GFCI trips: water in a box, failed photocell, or shared neutral between circuits.
- Dim light on a long run: voltage drop; shorten the route or upsize the wire.
Close Variation: Wiring An Outdoor Light Step By Step
Here’s a clean wall-sconce walk-through many homes use:
- Power off at the breaker. Prove dead at switch and exterior box.
- Layout: panel → switch (14/2 or 12/2) → light box. Keep a continuous neutral.
- Drill and run. Add bushings at sharp edges. Staple within reach of the box clamps.
- Mount the exterior box; seal to siding; set the gasket flat.
- Strip and splice grounds first. Add a pigtail to the device and strap.
- Land the switch common on the feed hot. Land the switched leg on the other screw.
- Tie neutrals in the back with a wirenut sized for the conductor count.
- At the light, connect white to white, switched hot to the fixture lead, ground to green.
- Install the fixture, snug the canopy, and caulk the top edge.
- Restore power and test. Add a dusk-to-dawn control if desired.
Wire Size, Breakers, And Distance
Most porch lights sit on a 15-amp branch with 14 AWG copper. If you’re adding a string of yard lights or a gate run, voltage drop can creep in. Keep drop near 3% on the lighting leg. Upsize to 12 AWG when the distance grows, or split the load across two paths from the switch box.
Wire Gauge And Approximate Distance (120 V Copper)
| Circuit | Gauge | Typical Run Guidance* |
|---|---|---|
| 15 A Lighting | 14 AWG | Up to ~75–100 ft for a few LED fixtures |
| 15–20 A Mixed | 12 AWG | ~100–150 ft with modest loads |
| 20 A Heavier | 10 AWG | ~150–200 ft where drop appears |
| Low-Voltage Path | 12–16 AWG | Transformer fed; distance varies by VA rating |
| Post Light + Receptacle | 12 AWG | Plan for GFCI and an in-use cover |
| Smart Switch Neutral | 14 or 12 AWG | Confirm box fill and device specs |
| Long Yard Run | 10–12 AWG | Upsize when flicker or dimming appears |
*Guidance assumes LED fixtures and a 3% drop target. Always check device current draw and total length.
Code Cues You Can Trust
Two rule sets shape this project: GFCI coverage outdoors and burial depth by wiring method. Industry explainers summarize the current scope for outdoor “outlets,” and trade tables outline minimum cover by raceway or cable type with notes on where 12-inch cover applies to GFCI-protected residential circuits in conduit. If you want the source language that underpins safe installs, OSHA’s wiring design page is a helpful anchor for good habits you can apply on a home job.
Smart And Low-Voltage Alternatives
A low-voltage landscape transformer is a neat option for path lights. It plugs into a GFCI receptacle and sends 12-volt power through outdoor-rated cable. No deep trench needed. For a porch or garage light that you flip nightly, a line-voltage switch stays simple and tidy, and a dusk-to-dawn sensor removes the daily chore.
Care And Maintenance
Check the gasket yearly and tighten loose canopy screws. Recaulk the top edge when you see staining. Replace brittle in-use covers. If a breaker trips after a storm, open the box, dry it, and replace any corroded connectors. A five-minute inspection each season keeps the fixture bright and safe.
Final Checks Before Power On
- Confirm the exact phrase “How to Wire an Outdoor Light” appears on your plan and labels so future you knows what the box feeds.
- Verify grounds are bonded and neutrals tied cleanly.
- Confirm box volume and device count meet listing and fill rules.
- Set the ladder aside, restore power, and test switch, sensor, and GFCI.
That’s the whole path for how to wire an outdoor light with confidence: plan the route, pick a compliant method, mount sturdy boxes, make dry splices, and verify operation with a simple tester. Follow the same rhythm for a second light or a post head and your exterior will look sharp night after night.