NEC Rules on Swimming Pools and Spas

The installation requirements of Art. 680 help keep people safe when they’re using swimming pools, hot tubs, spas, fountains, or hydromassage bathtubs. With the 2011 NEC revision, the definition of “dry-niche luminaire” now includes floor-mounted units to accommodate newer designs. The 2011 Code also adds a definition for “low-voltage contact limit.” The new definition contains the voltages discussed in Chapter 9 tables, so you don’t have to go to the back of the NEC to find the values.

Underground wiring

Table 680.10 contains a new allowance for nonmetallic underground raceways with concrete cover. The 2008 edition of this table gave requirements for nonmetallic raceways near a pool that doesn’t have concrete encasement. However, it didn’t provide guidance for such raceways that don’t have concrete encasement but do have concrete cover. This change makes it clear that you can install nonmetallic raceways with 4 in. of concrete cover near a pool without having to bury them 18 in. deep. An example of this might be raceways installed beneath a concrete pool deck.

Permanently installed pools

Permanently installed pools must comply with Parts I and II [680.20]. Thus, any cord- and plug-connected equipment, other than underwater luminaires, must have a copper equipment grounding conductor (EGC) no smaller than 12 AWG [680.7(B)]. Section 680.21(A)(5) guides you on how to size an EGC by referring to 250.122. Prior to this revision, however, it didn’t include the provision that the EGC be copper and no smaller than 12 AWG. This change corrects that inconsistency for cord- and plug-connected pool equipment.

The 2008 NEC added a requirement for pool motors to have GFCI protection whenever they’re rated 120V or 240V, 15A or 20A. The 2011 revision changed 680.21(C) to include 208V by replacing the “or” with “through.” The requirements have also been relocated to 680.21 from 680.22 (subsections in 680.22 renumbered accordingly).

Section 680.23(A) now accommodates LED luminaires. The new ones use DC power supplies — not transformers — for their power source. LED luminaire power supplies now must be listed.

Similar changes were made throughout Art. 680 to include the word “power supply” or “supplies” when referring to transformers. This allows the inclusion of new technologies that rely upon DC as well as AC power supplies.

The 15V threshold that has long been in this requirement was presumed to be a safe limit for AC when contact is possible. With the changing technologies of luminaires, this value no longer addresses all types of luminaires. Many are supplied by DC voltage, and many use nonsinusoidal voltage wave forms. This change reflects that by pointing you to the definition of “low-voltage contact limit” in 680.2. Similar changes were made throughout Art. 680.

Although there are listed low-voltage luminaires for swimming pools that don’t include a grounding means, the NEC hasn’t provided for them. Section 680.23(F) now allows for some low-voltageluminaires to be connected without an EGC. With this change, these luminaires (such as plastic LED luminaires) are viable options for swimming pools.

Previous NEC editions didn’t contain an allowance for Type MC cable as a feeder circuit for permanently installed swimming pools. A change to 680.25(A)(1) allows for this wiring method (if the cable isn’t subject to physical damage or corrosion), as shown in Fig. 1.

The wiring methods allowed in 680.25 have also been made into an easier-to-read list, reducing the likelihood of misreading the requirements.

Section 680.26 addresses equipotential bonding. The requirements have been revised extensively over the last few Code change cycles. Recent revisions have inadvertently left holes that fostered misinterpretation and misapplication. The 2011 Code sought to remedy these problems. For example, it addresses the connection of the copper bonding grid discussed in 680.26(B)(1)(b)(1). When nonconductive structural reinforcing steel is used in a pool, a bonding grid of 8 AWG copper conductors is required. Unfortunately, previous NEC editions didn’t address how to connect the grid to itself. The 2011 NEC states that this grid must be bonded together at all points of crossing in the grid, and the bonding means must comply with the connection provisions of 250.8.

A revision to 680.26(B)(2) clarifies the requirements for bonding the pool deck perimeter surfaces. Where the perimeter surface is less that 3 ft and separated by a wall (or fence), the bonding doesn’t need to extend to the other side of a wall if the wall (or fence) is at least 5 ft tall (Fig. 2).

Section 680.26(B)(7) has long required that “metal wiring methods and equipment” be bonded to the equipotential grid. A common question has been whether the “equipment” contemplated in 680.26(B)(7) applies to only “electrical equipment,” as defined in Art. 100, or if it applies to nonelectrical equipment also. The clarification provided in the 2011 NEC confirms that this requirement is to bond all metal parts, including, but not limited to, metal-sheathed cables and raceways, metal piping, metal awnings, metal fences, and metal door and window frames (Fig. 3). So this applies to all equipment, including metal fences and similar items. Differences in potential can exist between any metallic equipment, electrical or not. Thus, you bond it all unless it fits one of the exceptions:

• Metal parts separated from the pool by a permanent barrier that prevents contact by a person are not required to be bonded [680.26(B)(7) Ex 1].
• Metal parts greater than 5 ft horizontally from the inside walls of the pool are not required to be bonded [680.26(B)(7) Ex 2].
• Metal parts greater than 12 ft vertically above the maximum water level are not required to be bonded [680.26(B)(7) Ex 3].

Storable swimming pools

Amperage ratings of receptacles requiring GFCI protection have been added in 680.32. Previous NEC editions required you to provide GFCI protection to all 125V receptacles within 20 ft of a storable pool, but it didn’t state the amperage ratings. Now, the NEC is clear that only 15A and 20A, 125V receptacles within 20 ft of storable pools require GFCI protection (Fig. 4).

Spas and hot tubs

Sections 680.42 and 680.43 require that spas and hot tubs comply with Parts I and II of Art. 680, including the bonding provisions of 680.26 (except as modified by 680.42 for outdoor installations and 680.43 for indoor installations). Consequently, some inspectors have been requiring that a bonding grid (similar to the deck bonding for pools) be installed around indoor spas or hot tubs. While this was never the intent of the NEC, this section didn’t address that issue.

A new exception in the 2011 NEC makes it clear that an equipotential bonding grid isn’t required around the perimeter of an indoor listed self-contained spa or hot tub when installed above the finished floor [680.43 Ex 2].

A similar exception to 680.42(B) is the focus of a Tentative Interim Amendment that was passed by the NFPA Standards Council with an effective date of March 21, 2011. This provides an exception to the perimeter bonding requirements for a listed self-contained spa or hot tub meeting the following two conditions:

• Is installed according to manufacturer’s instructions on or above grade.
• The vertical measurement from all permanent perimeter surfaces within 30 in. horizontal of the spa to the top rim of the spa is greater than 28 in.

Switches have been prohibited within 5 ft of indoor spas and hot tubs [680.43(C)]. While this rule was probably intended to apply to all switches, the title of this subsection left room for argument. Previous NEC editions titled this rule “Wall Switches,” which implied a general-use snap switch. While snap switches do require a 5-ft separation from a spa or hot tub, so do circuit breakers, disconnect switches, safety switches, and all other types of switches. This revision should help the Code user understand the scope of this rule.

Over the past several Code cycles, a real effort has been made to remove exceptions. The NEC has been incorporating negative text (in the form of exceptions) into positive text (included in the rule itself).

The 2011 NEC change to 680.43(D) [Indoor Installation Bonding] is an example of this. It removed (former) Exception 2 and added a few words to 680.43(D)(2). While this change doesn’t make any technical difference at first glance, it does help the NEC user to understand which portion of 680.43(D) the (former) exception applied to. Many Code users were unclear if the exception was a carte blanche exception to 680.43(D) or just to 680.43(D)(4).

Hydromassage bathtubs

When a hydromassage tub is cord- and plug-connected, it’s common to find the receptacle beneath the tub, arranged such that it’s nearly impossible to see (much less use). Often, these receptacles are several feet away from the access opening, facing away from the person trying to access the receptacle. The 2011 Code solves this problem by requiring such a receptacle to be installed close to the access opening (within 1 ft) and facing toward the opening [680.73].

Section 680.74 has long required a hydromassage tub pump motor (if not double-insulated) to be bonded to a metal water piping system, if such a piping system is present.

There’s some possibility that a double insulated motor (which didn’t have a bonding jumper installed) might be replaced by a motor that isn’t double-insulated, resulting in a noncompliant installation. When replacing the motor, the installer must bond the new motor to the metal water piping system. But this could require extensive remodeling to access the metal water piping system. To solve this problem, the 2011 revision requires installers to route a bonding jumper to a double-insulated motor.

Wading through

Article 680 contains a lot of material and may seem overwhelming. Keep in mind that this article is divided into seven parts. The various parts apply to certain types of installations, so be careful to determine which parts of this article apply to what and where.

For instance, Part I and Part II apply to spas and hot tubs installed outdoors, except as modified in Part IV. In contrast, hydromassage bathtubs are only covered by Part VII. Read the details of this article carefully so you’ll be able to provide a safe installation. The overriding concern of Art. 680 is to ensure that people and electricity don’t inadvertently mix. Keep that concern in mind, and the various requirements will be easier to understand and apply.         

Holt is the owner of Mike Holt Enterprises, Inc., Leesburg, Fla. He can be reached at www.mikeholt.com.