One of the objectives of Article 680 is to provide some kind of very careful equipotential bonding to make certain that metal parts that people could contact cannot be at different potentials.

Ideally, all metal parts will also be at the same potential as the water. It is critical to recognize that when people are exposed to water, the shock hazard is increased if for no other reason than their skin resistance is likely to be decreased, making them susceptible to shock at lower voltages.