Based on the 2020 NEC

by Mark Lamendola

National Electrical Code Tips: Article 680 -- Swimming Pools, Fountains, and Similar Installations

Humans have enjoyed swimming pools for thousands of years, but they haven't always installed electric lights in them or circulated the water with pumps. Adding those and other electric features makes pools potentially lethal, and the requirements of Article 680 protect against such an outcome. This article covers similar installations, such as spas and hot tubs, too.

Similarly, we enjoy fountains in our cities and parks. We probably wouldn't enjoy being shocked by them. And again, Article 680 provides requirements that protect people.

The main job Article 680 tries to do is keep electricity and water separated, so that when people are in the water or in contact with related equipment, they are also separated from electricity.

  1. If you install any type of pool, tub, or fountain and supply it with lighting, pumps, or similar equipment, the installation must conform to Article 680 [680.1].
  2. You'll read in 680.6 that equipment must be grounded per Parts V, VI, and VII of Article 250. Unfortunately, this requirement is incorrect. Part V of Article 250 is about bonding, not grounding. Generally, you do not ground load-side equipment. You bond it. Because of incorrect wording throughout the NEC, you'll need to read the Article 100 definitions of bonding and grounding, and then apply some common sense to interpret which one a particular requirement really means.
  3. Overhead clearances can be a bit confusing with regard to pools. Fortunately, the NEC now (as of 2011) provides a means of determining clearances without pulling your hair and gnashing your teeth. In 2011, you'd have used Table 680.8 and Figure 680.8. In the 2020 NEC, you use Table 680.9(A) and Figure 680.9(A).
  4. For underground wiring requirements, see 680.11. Generally, you must bury metallic raceways at least 6 inches deep and nonmetallic at least 18 inches deep. If you have a good trenching tool, consider going deeper. The added protection can't hurt. Be sure you contact the local utility companies for a survey (typically, that means calling 811) and properly map out the route before trenching. Remember, you can dial 811 now or 911 later.
  5. The requirements for permanently installed pools are in Part II. Key concept: The branch circuits are permanently run in raceway and everything must be bonded back to the service through a "grounding" conductor run in the raceway with the current-carrying conductors.
  6. The requirements for storable pools are in Part III. Key concept: Cord-connected pumps, which are typical of these installations, must be double-insulated.
  7. The requirements for spas, hot tubs, and permanently installed immersion pools are in Part IV. Key concept: You must provide an emergency switch. This is a special kind of switch, and the on/off switch at the control system does not meet the requirement. Also, you can bond through a common equipment frame. But from an engineering standpoint, that should be an additional bonding path. It's best to run bonding conductors from point to point. You can't really overbond, but you can have problems if a bonding connection fails.
  8. The requirements for fountains are in Part V. Key concept: All equipment must be removable for servicing, without lowering the water level. So, for example, you can't embed a light into the fountain structure below the water line.
  9. The requirements for therapeutic pools and tubs are in Part VI. Key concept: You must bond certain things together [680.62(b)]. What you should do is bond everything metallic. This list of five items probably covers everything, but if you make a point of bonding everything metallic then you have certainty and not mere probability. Remember, bonding eliminates dangerous differences of potential.
  10. The requirements for hydromassage tubs are in Part VII. Key concept: Such tubs and their associated equipment must be on an individual branch circuit and protected by a readily available ground-fault circuit interrupter. And Part VIII has the requirements for electrically powered lifts.