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National Electrical Code (NEC) Rules for Outdoor Wiring
Outdoor Receptacles
The NEC includes specific rules for installing outdoor receptacles to ensure safety and prevent shock hazards. These rules include:
- GFCI Protection: All outdoor receptacles must have ground-fault circuit-interrupter (GFCI) protection to prevent electrocution.
- Accessibility: Homes must have at least one outdoor receptacle at the front and rear, readily accessible from the ground and no more than 6 1/2 feet above grade.
- Deck and Balcony Outlets: Attached decks and balconies with interior access must have a receptacle no more than 6 1/2 feet above the walking surface.
- Weather Resistance: Receptacles in damp locations (under protective covers) must be weather-resistant with a weatherproof cover.
- Wet Locations: Receptacles in wet locations (exposed to weather) must be weather-resistant with a weatherproof “in-use” cover.
- Pool Access: A permanent swimming pool must have access to a GFCI-protected receptacle no closer than 6 feet and no further than 20 feet from the pool edge, no higher than 6 1/2 feet above the pool deck.
- Pump Systems: Receptacles for pool and spa pump systems must be at least 10 feet from pools and spas if not GFCI-protected, and at least 6 feet away if GFCI-protected.
Outdoor Lighting
The NEC also provides rules for outdoor lighting to ensure safety and proper illumination. These rules include:
- Location Rating: Light fixtures in wet/exposed areas must be listed for use in wet locations. Fixtures in damp areas (protected by an eave or roof) must be listed for damp locations.
- Surface-Mounted Boxes: Electrical boxes for all outdoor fixtures must be raintight/weatherproof.
- GFCI Protection: Exterior light fixtures do not require GFCI protection.
- Low-Voltage Lighting: Low-voltage lighting systems must be listed by an approved testing agency and installed as per manufacturer’s instructions.
- Proximity to Pools: Low-voltage light fixtures must be at least 5 feet away from outside walls of pools, spas, or hot tubs.
- Transformer Placement: Transformers for low-voltage lighting must be located in accessible areas.
- Switch Location: Switches controlling pool or spa lights or pumps must be at least 5 feet from the outside walls of the pool or spa, unless separated by a wall.
Outdoor Cables and Conduits
The NEC regulates the use of cables and conduits for outdoor wiring to ensure electrical safety and protection from moisture and damage. These rules include:
- Exposed Wiring: Exposed or buried wiring/cable must be listed for outdoor use. Type UF cable is commonly used for residential outdoor wiring runs.
- Underground Burial: UF cable can be direct-buried without conduit with a minimum of 24 inches of earth cover.
- Conduit Use: Wiring buried inside rigid metal (RMC) or intermediate metal (IMC) conduit must have at least 6 inches of earth cover; wiring in PVC conduit must have at least 18 inches of cover.
- Backfill: Backfill surrounding conduit or cables must be smooth granular material without rocks.
- Low-Voltage Wiring: Low-voltage wiring (carrying no more than 30 volts) must be buried at least 6 inches deep.
- Underground to Above Ground Transitions: Buried wiring runs that transition from underground to above ground must be protected in conduit from the required cover depth or 18 inches (whichever is less) to its termination point above ground, or at least 8 feet above grade.
- Electrical Service Wires: Electrical service wires overhanging a pool, spa, or hot tub must be at least 22 1/2 feet above the water surface or diving platform.
- Data Transmission Wires: Data transmission wires must be at least 10 feet above the water surface in pools, spas, and hot tubs.
Call Before You Dig
Before digging anywhere on your property, call 811, the national “Call Before You Dig” hotline, to prevent damage to underground utilities and potential injury. Utility providers will mark their lines, allowing you to dig safely.
