Article 680 of the 2017 National Electrical Code (NEC) provides the requirements for electrical equipment associated with most types of manmade containers of water, whether permanently installed or storable. Excluded are large containers such as lakes formed by dams (the containers themselves aren't manmade). When it comes to understanding what is covered, the definitions in Sec. 680.2 complement the scope defined in Sec. 680.1.
The main concern of Art. 680 is to keep water and electricity apart from each other, thereby closing one path by which people and electricity aren't kept apart from each other. Obviously, you keep the current-carrying conductors and energized equipment out of the water, but you also provide a low-impedance path for undesired current to flow back to its source. Most of the Art. 680 requirements are about the particulars of achieving these two goals.
In Part 1, General Requirements, we find such things as:
- Grounding and bonding requirements (bonding is especially critical) [Sec. 680.6].
- Overhead conductor clearances (power and communications have different requirements) [Sec. 680.9].
- Equipment rooms and pits (no electrical gear can be in these) [Sec. 680.12].