Pools and Spas — Part 1 of 3

If Art. 680 of the National Electrical Code (NEC) has one overriding concern, it's to keep people and water separated from electricity. Article 680 applies to pools, spas, hot tubs, fountains, and similar bodies of water. Thus, it provides extensive requirements for the installation of electric wiring and equipment for such locations. The wiring also must comply with Chapters 1 through 4 of the Code, except as modified by Art. 680 [680.3].

Unless you understand the meaning of certain terms used in Art. 680, you run a high risk of misapplying the Code requirements. The first step in avoiding a lethal mistake is to take the time to understand the Art. 680 definitions (see Definitions on page 36).

Overhead conductor clearances

The “maximum water level” is an important term to understand. To obtain the correct overhead clearance for conductors, measure from the maximum water level to the overhead conductors [680.8]. That distance is the minimum clearance requirement, and it must be in conformance with Table 680.8.

The Table 680.8 clearances apply to permanently installed pools, storable pools, outdoor spas, outdoor hot tubs, fountains, diving structures, observation stands, towers, and platforms ( Fig. 1 ).

NEC Table 680.8 prohibits installing a pool (storable or permanent), outdoor spa, outdoor hot tub, or fountain under an existing service drop that isn't at least 22½ ft above the maximum water level. This requirement does not apply to an electric utility installing utility-owned overhead service-drop conductors over a permanently installed pool, storable pool, outdoor spa, outdoor hot tub, or fountain, because the Code does not cover such an installation under the exclusive control of an electric utility [90.2(B)(5)].

The clearance to communications cables is 10 ft (to the maximum water level). This rule doesn't prohibit a communications utility from installing a utility-owned communications overhead cable over a pool (storable or permanent), outdoor spa, outdoor hot tub, or fountain [90.2(B)(4)]. However, it does prohibit anyone from installing a pool (storable or permanent), outdoor spa, outdoor hot tub, or fountain under an existing communications utility overhead supply that isn't at least 10 ft above the maximum water level.

Electric water heaters

Most pools and hot tubs have heaters installed to increase the comfort level for the user and extend the usable season in milder climates. In some cases, such heaters may be fueled by natural gas or other fuels, but they are very often powered by electric water heaters.

The ampacity of the branch-circuit conductors and overcurrent devices for an electric pool water heater must be at least 125% of the total nameplate rating [680.9] ( Fig. 2).

Cord- and plug-connected equipment

Fixed or stationary equipment other than an underwater luminaire for permanently installed pools, storable pools, outdoor spas, outdoor hot tubs, or fountains are permitted to be cord- and plug-connected to facilitate removal or disconnection for maintenance or repair [680.7].

Except for storable pools, the cord must not exceed 3 ft (the NEC doesn't specify a maximum cord length for a storable pool pump motor). The cord must have a 12 AWG or larger copper equipment grounding conductor, and the cord must terminate at a grounding-type attachment plug [680.7(A) and (B)].

Underground wiring

Underground wiring is not permitted under permanently installed pools, storable pools, outdoor spas, outdoor hot tubs, or fountains [680.10]. If you think about what could happen during a cable fault, this makes perfect sense.

That same logic leads to a second rule regarding the same cables. You can't run them within 5 ft horizontally from the inside wall of the pool, spa, hot tub, or fountain, unless doing so is necessary for supplying the permanently installed pool, storable pool, outdoor spa, outdoor hot tub, or fountain equipment ( Fig. 3 ).

Where space limitations prevent wiring from being at least 5 ft away, the underground wiring must be installed in a complete raceway system. That raceway must be intermediate metal conduit (Art. 342), rigid metal conduit (Art. 344), or PVC conduit (Art. 352) listed for direct burial. The minimum cover is 6 in. for metal raceways and 18 in. for PVC conduits [Table 680.10].

Because the NEC isn't a design guide [90.1(C)], it doesn't provide all the information needed for a successful installation of the underground wiring. Before you start trenching, think about potential issues that may arise with your particular site. Some of these aren't even electrical, but they will affect how you implement Art. 680 requirements.

For example, what's the intended foot traffic? You don't want to route that raceway under walkways or paths likely to be used for motorized maintenance carts such as golf carts.

How can you identify an intended traffic path — especially on a new site where there isn't any grass or indication of traffic trails worn in the grass? Find out who the landscaper is and ask for the landscaping plan. This will also help you avoid digging up and rerouting the raceway so landscapers can dig holes for trees, shrubs, or a flagpole. Plan ahead in order to avoid conflicts that may affect the project cost and schedule.

Equipment rooms and pits

If equipment serves a permanently installed pool, storable pool, outdoor spa, outdoor hot tub, or fountain, the rooms or pits for that equipment must have adequate drainage to prevent water accumulation during normal operation or filter maintenance [680.11] ( Fig. 4 on page 36).

The NEC doesn't define “adequate” in this case, so what does it mean? Remember, Art. 680 seeks to keep people and water separated from electricity. If you happen to make contact with an energized part or conductor, it won't make much difference if you're standing in half an inch of water. The goal of “adequate” drainage should be to provide a dry, safe working area as well as to protect equipment from moisture damage.

Maintenance disconnecting means

Article 680 requires the installation of a maintenance disconnecting means for all equipment other than lighting [680.12]. The intent is to facilitate de-energization of equipment and provide lockout/tagout means for worker's safety.

The maintenance disconnecting means must be readily accessible and within sight of the permanently installed pool, storable pool, outdoor spa, outdoor hot tub, or fountain equipment. It must also be at least 5 ft from any of these, unless separated from the open water by a permanently installed barrier that provides a 5-ft reach path or greater. Measure the horizontal distance from the water's edge along the shortest path required to reach the disconnecting means.

Flowing with Art. 680

Part 1 of this three-part series coincides with Art. 680, Part I, which provides the general requirements for all electrical equipment covered by Article 680.

Part 2 coincides with Art. 680, Part II, Permanently Installed Pools. That installment will also cover permanently installed spas and hot tubs.

Part 3 begins with Art. 680, Part III, which is very short and addresses storable pools. We'll also cover the requirements in Part IV, Spas and Hot Tubs, and Part V, Fountains.

Whether you're working on a pool project or fountain project, you'll be referring to Art. 680, Part I throughout the installation — but your installation must also comply with the first four Chapters of the NEC. A key area to focus on is Art. 250, Part V, as well as the Art. 100 definitions related to grounding and bonding.

Sidebar: Definitions

Forming shell. A structure designed to support a wet-niche luminaire and mounted in the wall of a permanently installed pool, storable pool, outdoor spa, outdoor hot tub, or fountain.

Fountain. An ornamental pool, display pool, or reflection pool.

Hydromassage bathtub. A permanently installed bathtub with a recirculating piping system designed to accept, circulate, and discharge water after each use.

Maximum water level. The highest level that water reaches before it spills out.

Permanently installed swimming, wading, immersion, and therapeutic pools. Any of the following meet this definition:

Those constructed in the ground (or partially in the ground).
Those capable of holding water in a depth greater than 42 in.
All pools installed inside of a building, regardless of water depth, whether or not served by electrical circuits of any nature.

Pool. Manufactured or field-constructed equipment designed to contain water on a permanent or semipermanent basis and used for swimming, wading, immersion, or therapeutic purposes. The definition of a pool includes baptisteries (immersion pools), which must comply with the requirements of Art. 680.

Spa or hot tub. A hydromassage pool or tub designed for recreational or therapeutic use, typically not drained after each use.

Storable swimming pool. An aboveground pool with a maximum water depth of 42 in. Storable pools are sold as a complete package that consist of the pool walls, vinyl liner, plumbing kit, and pump/filter device. Underwriters Laboratories (UL) requires the pump/filter units to have a minimum 25 ft cord, to discourage the use of extension cords.

Wet-niche luminaire. A luminaire intended to be installed in a forming shell where the luminaire will be completely surrounded by water.