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): all metallic parts within 5 ft of pool/spa wall, pool reinforcing rebar (pre-stressed steel exempted), metallic light forming shells, metallic ladders + handrails (even removable), metallic diving board + supports, conductive pool deck within 3 ft (some jurisdictions 5 ft), heater + pump motor frames, metallic conduit/raceway within 5 ft, #8 AWG solid copper ground ring 18 - 24" below grade + 18 - 24" from pool wall.

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 within sight of equipment + readily accessible. 6 ft minimum from inside pool wall.

Receptacle placement

• 5 - 20 ft from inside pool wall: GFCI required (any height)
• 6 - 20 ft from spa or hot tub: GFCI required
• < 5 ft from pool: prohibited
• 5 - 10 ft from pool: low-voltage and GFCI receptacles for pool equipment only

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: USE-2 or THWN-2 in conduit (wet rated); all underground in conduit (no direct burial in pool zone). Non-metallic PVC schedule 40/80 OK; galvanized rigid OK; EMT NOT permitted. Burial depth: 6" PVC, 18" direct-buried cable (if permitted), 24" under driveway.

Disconnects: within sight of pump (≤ 6 ft), at light transformer/circuit, within sight of spa (≤ 6 ft). All readily accessible without tools.

Common inspection failures

Missing bonding within 5 ft (most common): retro-add #8 AWG solid copper to all required items with listed clamps to common point. Wrong wire type (THHN where THWN required): pull new wire or re-mark. Receptacle within 5 ft: relocate or enclose. Pool light without listed niche: replace with UL underwater fixture in proper niche. GFCI missing: add breaker + verify trip. No in-sight disconnect: install local 60A 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