10.3 Special Equipment (Pools, Industrial Machinery, Selected)

Swimming Pools, Fountains, and Similar Installations (Article 680)

Article 680 applies to permanently installed pools, storable pools, spas, hot tubs, fountains, and similar bodies of water. The Virginia exam heavily tests Part I (permanently installed pools), so this section focuses on those rules.

Motors and Circuits (680.20, 680.21)

Pool pump motors and circulation equipment must be supplied by a branch circuit with a wiring method suitable for the wet location. Per 680.21(C), all pool pump motors rated 60A or less at not over 150V to ground must have GFCI protection — whether connected by receptacle or direct connection. Per 680.21(D), replacement pump motors must also be provided with GFCI protection, even if the original motor was installed before the rule.

Receptacles (680.22)

The receptacle rules are the most-tested Article 680 rules:

• 680.22(A)(1) — At least one 15A or 20A, 125V receptacle must be installed on a general-purpose branch circuit, located between 6 ft and 20 ft from the inside wall of the pool. This receptacle may be no more than 6½ ft above the floor/platform.
• 680.22(A)(2) — Receptacles for circulation/related equipment must be at least 6 ft from the inside pool wall and must be GFCI protected.
• 680.22(A)(3) — Receptacles for non-circulation loads must be at least 6 ft from the pool wall.
• 680.22(A)(4) — All 15A or 20A, 125V receptacles located within 20 ft of the inside pool wall must be GFCI protected.
• Taken together, (A)(2) and (A)(3) prohibit any receptacle within 6 ft of the inside pool wall. Do not cite 680.22(B) for this — that subsection covers luminaires, lighting outlets, and ceiling-suspended (paddle) fans.
• 680.22(C) — A maintenance disconnecting means must be installed, readily accessible, and located at least 5 ft horizontally from the inside pool wall and within sight of the pool equipment.

Equipotential Bonding (680.26)

The purpose of 680.26 is to eliminate voltage gradients in the pool area. A solid 8 AWG bare or insulated copper bonding conductor (minimum) must bond together the parts listed in 680.26(B)(1)–(B)(7):

1. Conductive pool shell — structural reinforcing steel of a concrete pool shell, or a bonded copper grid for non-conductive shells.
2. Perimeter surfaces — a copper ring of 8 AWG solid copper (or larger), placed 18–24 in. from the inside pool wall, secured 4–6 in. below subgrade, attached at four points around the perimeter.
3. Metallic components — metal fittings, ladders, handrails, diving boards.
4. Underwater lighting forming shells.
5. Metal fittings within the pool (skimmer housings, etc.).
6. Electrical equipment — pool pump motor and other electrical equipment associated with the pool water circulation system.
7. Fixed metal parts — any fixed metal parts within 5 ft horizontally of the inside pool wall and within 12 ft vertically of the maximum water level — including door frames, window frames, fences, and metal awning frames.

Note: Bonding is not the same as grounding. Bonding ties the listed parts together to eliminate voltage differences; grounding ties equipment to earth. Article 680 bonding uses a separate 8 AWG bonding conductor and is required regardless of whether the metal part is grounded or not.

GFCI for Pool Equipment (680.32)

All 125V, 15A and 20A receptacles within 20 ft of the pool water must be GFCI protected. Luminaires, lighting fixtures, and submersible equipment rated 15A or less and 150V to ground or less must also be GFCI protected.

Worked Example — Residential Pool Receptacle and Bonding Layout

A homeowner installs an in-ground pool. The electrician must:

1. Provide a general-purpose receptacle between 6 ft and 20 ft from the inside pool wall, GFCI protected (680.22(A)(1) and (A)(4)).
2. Provide a GFCI-protected receptacle for the pump motor at least 6 ft from the pool wall, on a dedicated branch circuit sized to the motor full-load current (680.22(A)(2) and 680.21(C)).
3. Install a maintenance disconnect at least 5 ft horizontally from the pool wall, in sight of the pool equipment (680.22(C)). The disconnect may be lockable per 110.25 if not in sight.
4. Install an 8 AWG solid copper perimeter bonding ring 18–24 in. from the inside pool wall, 4–6 in. below subgrade, attached at four points (680.26(B)(2)).
5. Bond the reinforcing steel, the pump motor, the metal ladder/handrail, underwater light forming shells, and any fixed metal awning frame within 5 ft horizontally and 12 ft vertically of the pool (680.26(B)(1)–(B)(7)).
6. Thread the GFCI protection to the pump motor branch circuit so replacement motors also have GFCI (680.21(D)).

Common Traps

• Placing a receptacle at 4 ft from the pool wall — prohibited by 680.22(A)(2) and (A)(3). The minimum is 6 ft.
• Forgetting the perimeter surface bonding ring 18–24 in. from the pool wall (the 2020 NEC added the specific dimension; older codes just said "perimeter").
• Bonding only the pump motor and not the metal ladder or awning frame within 5 ft horizontally.
• Not installing a maintenance disconnect — this is separate from the pump motor disconnect and must be at least 5 ft from the pool wall.
• Assuming the perimeter surface bonding ring replaces grounding — bonding does not replace the equipment grounding conductor required by Article 250.

Industrial Machinery (Article 670)

Article 670 applies to industrial machinery — machine tools, assembly lines, and similar equipment permanently installed in industrial facilities.

Nameplate Marking (670.3)

Each machine must have a permanent nameplate listing:

• Full-load current of the machine (or the largest motor and the total connected load).
• Voltage and phases.
• Short-circuit current rating (SCCR) per 670.5 — the machine may not be installed where the available fault current exceeds the marked SCCR.
• Overcurrent protection ratings.
• The manufacturer's name and the machine identification.

Supply Conductors (670.7)

Supply conductors to the machine must have an ampacity not less than the full-load current marked on the nameplate. If the machine has multiple motors, the supply conductor ampacity is calculated per 430.24 (sum of all motor full-load currents plus 25% of the largest). Overcurrent protection must be sized per Article 430.

Disconnecting Means (670.7)

The disconnect must:

• Be rated in amperes not less than the machine full-load current.
• Be capable of being locked in the open position per 110.25 if not in sight of the machine.
• Disconnect all ungrounded conductors simultaneously.
• Be identified as the machine disconnect.

Per 670.5, a machine must not be installed if the available fault current at the line terminals exceeds the marked short-circuit current rating. This is a key exam point — installers must verify the SCCR before installation.

X-Ray Equipment (Article 660)

Article 660 covers x-ray equipment for diagnostic, therapeutic, and industrial use. Key rules: the branch circuit must be sized at not less than the momentary rating of the x-ray equipment (or the continuous rating if the momentary is not marked); a disconnect must be provided, lockable and in sight of the control; secondary circuits must be guarded. The work area and the control station are considered separately for wiring method purposes.

Induction Heating (Article 665)

Article 665 covers induction heating equipment — used for forging, heat treating, brazing, and similar industrial heating. The supply conductors must be sized to the nameplate input current; a disconnect must isolate the equipment; the induction coil is considered the load and requires guarding against accidental contact.

Electroplating (Article 668)

Article 668 covers electroplating, anodizing, and electropolishing lines. DC conductors and the plating tank area must be isolated from the AC system; the bonding of tank structures is required to prevent stray currents; a disconnect must isolate the rectifier/DC source from the supply.