Pool + Spa Electrical (NEC Article 680)

Why this matters

Pool + spa electrical kills people every year - current leakage into water + ungrounded equipment + improperly-bonded handrails create lethal stray voltage. NEC Article 680 is the most stringent residential code section + is heavily inspector-scrutinized. The electrician who knows NEC 680 cold sells + installs + pool electrical work cleanly + passes first inspection; the generalist who guesses gets repeated rejections + ends up paying for rework + permit re-pulls. Customer's pool builder will hand you the work IF you can deliver code-compliant + on schedule.

NEC 680 scope

Permanent pools, spas, hot tubs, swimming pools, fountains, hydrotherapy tanks. Covers:

• Equipotential bonding (the critical part)
• Receptacle locations + GFCI requirements
• Light fixtures (underwater + adjacent)
• Equipment grounding + bonding
• Wire types + conduit
• Disconnects + service

Equipotential bonding (the critical part)

Single most important + most-failed inspection issue. Bonding equalizes voltage between all conductive parts so a swimmer can't be electrocuted by stray voltage.

What must be bonded (NEC 680.26): fixed metal parts within 5 ft horizontally of the pool/spa wall, the pool's unencapsulated structural reinforcing steel (steel that is ENCAPSULATED in a nonconductive compound is the case that is exempt, and it is exempt only because you then owe an alternate copper conductor grid in its place), metallic light forming shells, metallic ladders + handrails (even removable ones), metallic diving board + supports, the perimeter surface out to 3 ft horizontally from the inside wall, heater + pump motor frames, and metallic conduit/raceway within 5 ft.

Where the perimeter is bonded with a copper conductor rather than existing reinforcing steel, that conductor is 8 AWG solid bare copper, following the contour of the perimeter, set 18 to 24 in. from the inside walls of the pool and only 4 to 6 in. below the subgrade. The 18 to 24 figure is the horizontal offset. It is not the depth, and burying the ring a foot and a half down is a common and expensive way to fail the inspection.

Bonding conductor: solid copper #8 AWG min, listed bonding clamps (NOT regular ground clamps), all routed to single point, connected to pump motor terminal. Bonding is NOT the same as equipment grounding - bonding interconnects metal parts; grounding takes fault current back to service. Both required. Equipotential pool deck within 3 - 5 ft often must be wire mesh bonded to the system (NEC interpretation varies by jurisdiction).

GFCI requirements

All pool + spa equipment on GFCI:

• Pump + heater + lights - yes
• Receptacles within 20 ft of pool wall - yes, GFCI
• Outdoor lighting near pool - yes
• Hot tub or spa - entire unit GFCI

Disconnect: required for all utilization equipment, readily accessible, within sight from the equipment it serves, and located at least 5 ft horizontally from the inside walls of the pool, spa or hot tub. Note this is 5 ft, not the 6 ft the receptacle rule uses.

Receptacle placement

Two different dimensions live in Article 680 and they get swapped constantly. Receptacles are a 6 ft rule. The equipment disconnect is a 5 ft rule. Learn them as a pair so you stop reaching for the wrong one.

• Closer than 6 ft to the inside pool wall: no receptacles, measured as the shortest path a cord would take
• 6 to 10 ft: a receptacle supplying a pool pump motor is permitted here, but only as a SINGLE receptacle, of the locking and grounding type, GFCI-protected
• 6 to 20 ft: where the general-purpose receptacle required at a dwelling-unit pool goes
• Within 20 ft of the inside wall: every 125 V, 15 and 20 A receptacle needs GFCI, at any height
• Spa or hot tub: same 6 ft floor, same 20 ft GFCI reach

Distances are measured as the shortest path the cord would follow, not straight through a wall or a permanent barrier.

Underwater lighting

Low-voltage (typical residential, 12 - 14 V):

• Most common; safer in water
• Transformer in dry location ≥ 5 ft from pool wall
• GFCI required on supply
• Niche-mounted OR LED inline

Line-voltage (older installations, 120 V):

• More stringent requirements
• Forming shell bonded
• Conduit + bonding back to bond grid
• GFCI required at transformer/circuit

Niche fitting: stainless or brass forming shell embedded in pool wall; light fixture mounts in niche; cord goes through conduit. Niche must be bonded.

Equipment + wire + disconnects

Pump + filter equipment outdoors or in equipment room; disconnect within sight + readily accessible; grounded + bonded. Gas heater: gas per IFGC + electrical for ignition/controls/pump. Electric/heat-pump heater: 240V 30 - 60A typical, GFCI required (heat pump exception in specific conditions). Spa control panel adjacent to spa, GFCI breaker, bonded.

Wire: wet-rated conductors only, THWN-2 or USE-2, and treat every raceway underground and in the equipment area as wet. Non-metallic PVC schedule 40/80 OK; rigid metal and IMC OK; EMT is limited to where the code allows it and is a poor choice in the corrosive environment around a pool pad, so most inspectors expect not to see it there.

Burial depths come from NEC Table 300.5 and the common field error is attaching them to the wrong raceway. Read the row:

• Rigid metal conduit and IMC: 6 in.
• PVC and other nonmetallic raceway listed for direct burial: 18 in.
• Direct-buried cable or conductors: 24 in.
• Under the driveway of a one- or two-family dwelling: 18 in., for both the direct-burial and the raceway cases

Disconnects: within sight from the pump, within sight from the spa, and at the light transformer circuit. "Within sight" is a defined term and it means visible AND not more than 50 ft away, which is not the same as being right beside it. All readily accessible without tools, and all at least 5 ft horizontally from the water.

Common inspection failures

Missing bonding within 5 ft (most common): retro-add 8 AWG solid copper to all required items with listed clamps to a common point. Wrong wire type (THHN where a wet-rated conductor is required): pull new wire. Receptacle inside the 6 ft restricted space: relocate it. Pool light without listed niche: replace with a listed underwater fixture in a proper niche. GFCI missing: add breaker + verify trip. No in-sight disconnect: install one sized for the load, which on a 240 V pump means a 2-pole device, not a single-pole. Conduit too shallow: re-trench or add concrete/rigid cover. Bonding to wrong reference: must connect to pool rebar or equipotential plane, not arbitrary ground.

New construction sequence

Builder pours pool shell with rebar stub for bonding. Electrician bonds rebar BEFORE concrete cures (#8 AWG solid copper from rebar to pump motor location). Equipment pad install (pump, heater, filter, transformer). Lighting niche set during shell pour. Conduit runs to equipment pad + lighting + disconnects. Equipotential plane in deck pour. Final electrical install + bonding terminations. Inspection + commissioning with builder + customer.

Retrofit / repair

"Pool light not working":

• Verify GFCI not tripped
• Check transformer output voltage
• If line-voltage light, check breaker + transformer
• If LED, may need replacement bulb / fixture
• Niche pull-out for replacement (drain pool typically)

"Pump trips GFCI":

• Wet motor connections
• Insulation breakdown
• Bond connection failed (creates ground path)
• Aging motor
• Replace motor OR repair connections

"Stray voltage tingle in pool" (RED FLAG):

• Bonding failure somewhere
• IMMEDIATE shut down + diagnostic
• Tester / fluke meter measure voltage between bonded points
• Recheck every bonding connection

References

• NEC 2023 Article 680 (Swimming Pools, Fountains, + Similar Installations)
• IRC + IPC pool sections (where pool plumbing intersects)
• Local AHJ pool electrical inspectors (varies by jurisdiction)
• Manuall internal: Annual Electrical Inspection, Conductor Ampacity Reference