Outdoor wiring faces harsher conditions than indoor installations as it is exposed to moisture, sunlight, and mechanical damage. Below is a comprehensive guide to NEC rules for outdoor receptacles, lighting, conduit, boxes, pool zones, and more.

1. Outdoor Receptacles (NEC 210.8, 210.52, 406.9, 680.22, 210.12)

• All 15- and 20-amp, 125-volt outdoor receptacles must have GFCI protection.

• Exception: Some snow-melting or deicing equipment may be exempt if powered by an inaccessible outlet.

• Receptacles must be weather-resistant (WR-rated) and installed in weatherproof enclosures.

• Receptacles require a weather-tight cover in damp locations (e.g., under a porch roof).

• In wet locations (e.g., exposed to rain), they must use an in-use weatherproof cover that seals even when something is plugged in.

• At every one-family dwelling, at least one receptacle must be installed at the front and one at the rear of the building.

• Decks, balconies, and porches attached to the home and accessible from indoors must have at least one receptacle.

• The outlet must be placed no more than 6.5 feet above the walking surface.

• All outdoor receptacles must be mounted no higher than 6.5 feet above grade and must be readily accessible.

• For permanent pools, a general-purpose GFCI-protected receptacle must be installed:

• No closer than 6 feet and no farther than 20 feet from the pool’s edge.

• Installed no higher than 6.5 feet above the pool deck.

• Receptacles for pool or spa pump systems must follow these distance rules:

• With GFCI: minimum 6 feet from the water.

• Without GFCI: minimum 10 feet.

• Must be single-use receptacles serving only the pump or equipment.

• Note: AFCI protection may also be required if the circuit originates in or serves indoor areas where AFCI is mandated (e.g., bedrooms), per NEC 210.12.

2. Outdoor Lighting (NEC 410.10, 680.22(B), 411.3, 314.15)

• All fixtures must be listed for wet or damp locations, depending on their placement:

• Wet-location-rated for fully exposed areas.

• Damp-location-rated for sheltered spots like under eaves.

• Fixtures must be securely mounted to listed weatherproof boxes, with all connections sealed against moisture intrusion.

• Standard exterior lighting does not require GFCI, unless installed near a pool or spa.

• Low-voltage lighting systems must either be:

• Listed as a complete system, or

• Built from individually listed components (e.g., transformer, luminaires, cabling).

• Low-voltage luminaires must be placed at least 5 feet from the walls of pools, spas, or hot tubs.

• Transformers for low-voltage systems must remain accessible, not buried or sealed in inaccessible spaces.

• Switches for pool/spa lights or pumps must be located at least 5 feet from the water unless physically separated by a wall.

3. Conduit and Cable Protection (NEC 300.9, 352, 358, 344)

• All conduit outdoors is considered to be in a wet location, even if not exposed.

• Therefore, all conductors inside must be wet-rated (e.g., THWN-2).

• Allowed outdoor conduit types include:

• PVC (Schedule 40 or 80) – must be sunlight-resistant; use Schedule 80 if subject to damage.

• EMT (Electrical Metallic Tubing) is permitted above ground only.

• RMC (Rigid Metal Conduit) and IMC (Intermediate Metal Conduit) are approved for exposed or buried installations.

• Expansion fittings are required on long outdoor PVC runs to prevent stress from thermal expansion.

• UF cable is suitable for outdoor use, but must be protected by conduit where exposed to damage.

• NM cable (Romex) is not allowed outdoors, even if covered or enclosed.

Burial Depth Reminder

If your outdoor wiring runs underground, NEC Article 300.5 sets minimum burial depths — generally 6 to 24 inches, depending on conduit type, voltage, and GFCI protection. For a full breakdown of these requirements, see our dedicated guide:

How Deep Does an Electrical Wire Need to Be Buried?

4. Boxes, Splices, and Enclosures (NEC 314, 300.15)

• All boxes and enclosures must be rated for outdoor/wet location use.

• Entries and exits must be sealed using listed watertight fittings.

• Splices must be made inside approved weatherproof enclosures, using connectors rated for wet conditions.

• All outlet, junction, and switch boxes used outdoors must have weatherproof covers, whether or not devices are plugged in.

5. Pools, Spas, and Water Features (NEC 680)

• A general-purpose receptacle must be:

• Placed 6–20 feet from the edge of the pool or spa.

• GFCI-protected.

• Mounted no higher than 6.5 feet above the pool deck.

• Pump receptacles must be:

• At least 6 feet away if GFCI-protected.

• At least 10 feet away if not GFCI-protected.

• Dedicated single outlets serving only the pump or spa motor.

• Luminaires within 5 feet of water must be low voltage, separated by a barrier, or mounted at a code-compliant height.

• All metal components (railings, ladders, fencing, etc.) must be bonded and grounded to eliminate shock hazards.

• Switches for pool and spa equipment must be located at least 5 feet from the water unless separated by a permanent barrier.

6. Support and Securing of Cables and Conduit (NEC 334.30, 352.30, 358.30)

• UF cable must be supported every 4.5 feet, and within 12 inches of every box.

• PVC conduit must be supported every 3 feet.

• EMT conduit must be supported every 10 feet and within 3 feet of each termination point.

• All supports, straps, and fasteners must be weather-resistant and approved for outdoor use.

7. Protection from Physical Damage (NEC 300.4, 300.5(D))

• Any outdoor wiring exposed to impact, abrasion, or other physical damage must be shielded or enclosed in conduit.

• Low-voltage wiring, even though less hazardous, must still be protected when routed through vulnerable areas like fence lines, garden beds, or along structures.

8. Use of Flexible Cords Outdoors (NEC 400.7, 400.8)

• Flexible cords (e.g., extension cords) cannot be used in place of permanent outdoor wiring.

• Temporary cords such as SJTW or SJEOW types must be listed for outdoor use.

• Permanent outdoor fixtures and appliances (like pumps or lights) must be wired with fixed, code-approved methods — never plug-in cords long-term.

9. Outdoor Disconnects (NEC 430.102, 680.12)

• Equipment such as AC units, spas, and pumps must have a readily accessible disconnect within sight of the equipment.

• Disconnects must be weatherproof, listed for outdoor use, and installed at least 5 feet from the edge of any pool or spa to protect service personnel.

10. Overhead Clearances for Conductors Above Pools (NEC 680.8)

• Service drop conductors must be at least 22.5 feet above the surface of the pool or diving platform.

• Communication cables (e.g., phone or internet lines) must be at least 10 feet above the water surface.

11. Cables Commonly Used for Outdoor Wiring

The NEC limits what types of cable you can use in different conditions:

• UF-B Cable

• Used for direct burial and above-ground outdoor runs (if protected from physical damage).

• Commonly powers outdoor outlets, lights, sheds, and small buildings.

• THWN-2 Conductors in Conduit

• Used when cables must be run through PVC, EMT, or RMC conduit.

• Ideal for underground feeders, outdoor lighting poles, or runs under driveways and patios.

• XHHW / XHHW-2

• Cross-linked polyethylene insulation for higher temperature and moisture resistance.

• Used in wet locations, including conduit installations and some commercial outdoor feeders.

• USE-2 Cable

• Designed for underground service entrance and direct burial.

• It is not rated for indoor use; it is typically used by utilities, not homeowners.

• RHH / RHW-2 Cable

• Flame- and moisture-resistant, suitable for conduit in outdoor wet locations.

• Often used in commercial and industrial outdoor setups.

• Low-Voltage Landscape Lighting Cable

• Rated for direct burial up to 30V.

• Used for garden lights, irrigation systems, and other outdoor low-voltage circuits.

Each cable type must match both the environment (e.g., wet, exposed, underground) and installation method (e.g., direct burial, conduit, surface-mounted).

Final Thoughts

Key considerations for outdoor outlets include:

• GFCI and WR protection

• Weather-sealed boxes and covers

• Approved conduit types and wet-rated wires

• Rules near water (pools, spas)

• Secure support and mechanical protection

• Fixed wiring methods only — no flexible cord substitutes

• Clearance and disconnect requirements

Always consult the latest NEC code and your local authority having jurisdiction (AHJ) before starting any outdoor installation, especially when digging.