Article 680 of the National Electrical Code (NEC) governs the installation of electrical systems for swimming pools, fountains, hot tubs, spas, wading pools, decorative pools, artificial waterfalls, therapeutic tanks, and similar bodies of water. Its main focus is preventing electrical shock and fire hazards near water.

The scope of the article covers electrical installations associated with:

• Pools (permanently and storable)

• Spas and hot tubs

• Fountains

• Hydromassage bathtubs

• Therapeutic tanks

• Ponds, lagoons, and similar installations

Here is an overview of everything important stated in this article:

General Requirements For Water-Based Installations

• Equipment must be installed per manufacturer instructions and by all applicable listing and labeling.

• GFCI (Ground-Fault Circuit Interrupter) protection is required for nearly all pool- and spa-related circuits, including pumps, electrical heaters, lighting, and convenience outlets near water.

• Bonding of all conductive parts within 5 feet of the water is mandatory for shock prevention— must use #8 AWG solid copper (aluminum is not permitted for bonding).

• All metallic parts of equipment must be grounded with copper or insulated, corrosion-resistant aluminum conductors sized correctly, securely connected to grounding terminals or bars, and protected from physical damage.

• Voltage to ground must not exceed 150V for any circuit within 5 feet of the water (or underwater).

• Only listed and labeled equipment (pumps, lights, transformers, heaters, controls, etc.) shall be used and must be marked for pool, spa, or fountain use.

• Wet-location-rated wiring methods (e.g., THWN, XHHW, listed MC) and enclosures are required for all outdoor or near-water installations.

• No NM-B (Romex), BX, or unlisted MC cable is allowed near pools, spas, or fountains.

• Disconnects must be readily accessible, in sight of the equipment they control, and located at least 5 feet from the inside wall of the pool or spa.

• Underground wiring must be kept at least 5 feet away from the inside pool wall unless installed in rigid conduit (RMC, IMC, or listed PVC) at proper burial depth (at least 6 inches for RMC and IMC, at least 18 inches for PVC 80). Underground wiring without the conduit is strictly prohibited, even if it is rated for direct burial.

• Only qualified personnel should perform pool, spa, or water feature electrical installations.

• Overhead power lines must maintain a minimum clearance of 22.5 feet above the water and 10 feet horizontally from the pool’s edge, while communication lines must be at least 10 feet above the water.

Pool and Spa Luminaires

• Wiring to underwater luminaires must be in:

• RMC, IMC, PVC, EMT, or flexible metallic conduit if within allowable lengths.

• All conductors must be insulated copper rated at least 90°C.

Bonding

• Bonding conductors must be:

• Solid copper, not smaller than 8 AWG, unless otherwise specified.

• Run outside of conduit or cable assembly for visual inspection unless inside listed assembly rated for bonding.

Specific Cable Types Allowed

Here are cable types commonly accepted if marked for wet locations and used as permitted:

• THWN or THWN-2 conductors in conduit

• XHHW/XHHW-2 in conduit

• Type MC Cable — must be listed for wet locations and corrosion-resistant

• Type UF Cable — allowed only for storable pools and limited outdoor use

• Hard usage flexible cord (e.g., Type S, SO, SJ) — only where explicitly allowed (like pool pump cords and lights). The use is limited to short lengths of approximately 3 ft. #12 AWG min, hard usage rated, ≤3 ft, GFCI protected.

Prohibited Cable Types

• NM-B (Romex): Never allowed in wet or outdoor pool environments

• Any non-wet-rated cable

• Unlisted MC for wet locations

• AC cables

• Service entrance cables, as they are not listed for underground or pools.

• Tray cables are not allowed unless part of a listed system is approved for pool applications.

Copper vs. Aluminum Conductors In Water Installations

NEC Article 680 doesn't explicitly ban aluminum conductors, but it strongly favors copper, and in some cases requires it, especially for safety-critical parts. Here is the breakdown:

• Bonding conductors must be solid copper, not smaller than 8 AWG.

• Aluminum is not allowed for bonding due to corrosion risk in moist, chemical-laden pool environments.

• Copper or aluminum conductors are permitted for grounding by NEC Article 250.

• Copper is strongly preferred for wet and corrosive pool areas.

• Where used, aluminum grounding conductors must be insulated and protected from corrosion — which is often impractical around pools.

• Both copper and aluminum are permitted if listed and properly installed for branch circuits and feeders.

• Aluminum must be installed carefully:

• Properly sized (larger than copper for the same ampacity)

• Terminated with aluminum-rated lugs.

• Protected against moisture and corrosion

• Many pool-rated devices and terminals are copper-only.

• Even if aluminum is technically allowed for feeders, compatibility issues often make copper the default in real-world pool installations.

In general, even though aluminum is allowed for some elements of water installations, aluminum is a default.

Receptacle Requirements

• A minimum of one 15- or 20-amp GFCI-protected outlet must be provided between 6–20 feet from the pool.

• No receptacles are allowed within 6 feet of the pool wall.

• All outlets outdoors within 20 feet of the pool must have GFCI protection.

• Switching devices must be at least 5 feet from the inside walls of pools/spas unless separated by a barrier.

Lighting Requirements

• Low-voltage lighting (15–30V) is permitted if isolated via transformer and listed.

• 120V lighting must be GFCI protected and located at least 5 feet above water or 12 feet away horizontally.

• No lighting within 5 feet vertically or 5 feet horizontally of the pool edge unless it's listed and approved for such use.

Metallic Parts Not Requiring Bonding

• Certain parts are exempt from bonding, like:

• Isolated drain fittings

• Small metal parts more than 5 ft from the pool wall

• Metal window/door frames not likely to become energized

Inspections and Accessibility

• All junction boxes, ground connections, and transformers must be:

• Accessible without damaging building finishes

• Clearly labeled and weatherproof if outdoors

GFCI Protection Threshold

• 125V and 240V circuits near water must be GFCI protected

• Most outdoor and pool-related equipment is limited to 120V or 240V single-phase; three-phase power is generally avoided unless in large commercial settings.

NEC Article 680: Universal Circuit Requirements By Equipment Type

1. Pool Pump Motor

• Breaker: 15–20A

• Wire: #12 AWG

• Cable Type: THWN or XHHW in RMC, IMC, EMT, or listed MC for wet locations

• Notes: Dedicated GFCI circuit; size per motor full-load amps.

2. Pool Heater

• Breaker: 30–50A

• Wire: #10–#6 AWG

• Cable Type: THWN or XHHW in conduit; listed MC allowed

• Notes: GFCI required; size to 100% of nameplate rating.

3. Underwater Lighting

• Breaker: 15–20A

• Wire: #14–#12 AWG

• Cable Type: THWN in conduit; low-voltage lighting must use listed pool-light cable

• Notes: Transformer-fed, low-voltage preferred; must be listed and GFCI-protected.

4. Above-Ground Lighting

• Breaker: 15–20A

• Wire: #14–#12 AWG

• Cable Type: THWN in conduit or listed wet-rated MC

• Notes: GFCI required; install ≥7.5 ft above water (indoor).

5. Convenience Outlet

• Breaker: 15–20A

• Wire: #14–#12 AWG

• Cable Type: THWN in conduit; UF not allowed unless listed for assembly use

• Notes: GFCI required; must be 6–20 ft from pool.

6. Pool Cover Motor

• Breaker: 15–20A

• Wire: #14–#12 AWG

• Cable Type: Listed flexible cord for listed pool cover systems or THWN in conduit

• Notes: GFCI required; listed device; weatherproof installation.

7. Audio Equipment

• Breaker: 15A

• Wire: #14 AWG

• Cable Type: Listed Class 2 or low-voltage wet-rated cable

• Notes: Must meet low-voltage contact limits or be isolated and GFCI-protected.

8. Hydromassage Bathtub

• Breaker: 15–20A

• Wire: #14–#12 AWG

• Cable Type: NM cable allowed for indoor only, but often THWN in conduit preferred

• Notes: Dedicated GFCI circuit; bonding required for internal metal parts.

9. Hot Tub / Spa

• Breaker: 40–60A

• Wire: #8–#6 AWG

• Cable Type: THWN in RMC/IMC/PVC or listed MC for wet locations

• Notes: 240V dedicated GFCI circuit; bonding grid; disconnect ≥5 ft away.

10. Pool Subpanel Feeder

• Breaker: 60–100A

• Wire: #6–#3 AWG

• Cable Type: THWN in RMC/IMC/PVC or listed MC cable for wet locations

• Notes: Must include insulated ground; feeder must be GFCI-protected or feed GFCI-protected circuits.

11. Fountain Pump

• Breaker: 15–20A

• Wire: #12 AWG

• Cable Type: THWN in conduit; listed wet-rated MC

• Notes: GFCI required; listed pump; low-voltage preferred.

12. Interactive Water Features / Splash Pads

• Breaker: 15–20A

• Wire: #12 AWG

• Cable Type: THWN in RMC, IMC, or PVC

• Notes: GFCI for all circuits; bonding grid required; listed components.

13. Transformer (Primary Side)

• Breaker: 15–20A

• Wire: #14–#12 AWG

• Cable Type: THWN in conduit

• Notes: Size to transformer input load; GFCI recommended.

14. Transformer (Secondary Side)

• Breaker: Varies by load

• Wire: #12–#10 AWG

• Cable Type: Listed low-voltage wet-location cable

• Notes: Low-voltage wiring; must be protected from damage.

15. Spas (General)

• Breaker: 40–60A

• Wire: #8–#6 AWG

• Cable Type: THWN in conduit or listed MC for wet locations

• Notes: Same as hot tubs; bonding, GFCI, and disconnect rules apply.

16. Wading Pools

• Breaker: 15–20A

• Wire: #12 AWG

• Cable Type: THWN in conduit

• Notes: GFCI required; bonding grid; follow all pool rules.

17. Decorative Pools / Waterfalls / Reflection Pools

• Breaker: 15–20A

• Wire: #12 AWG

• Cable Type: THWN in conduit or listed MC for wet locations

• Notes: GFCI and bonding are required; all components must be listed and wet-rated.

18. Therapeutic Tanks

• Breaker: 15–20A

• Wire: #12 AWG

• Cable Type: THWN in conduit or wet-rated cable

• Notes: GFCI required; bonding for metal piping and accessible parts.

19. Receptacles Around Pool

• Breaker: 15–20A

• Wire: #14–#12 AWG

• Cable Type: THWN in conduit or listed MC for wet locations

• Notes: Must be 6–20 feet from the pool, GFCI protected, and weather-resistant if outdoors.

 Nassau National Cable sells all wire and cable approved for use under the NEC article 680.