Earthing & Bonding
Electrical earth bonding is the practice of intentionally electrically connecting all exposed metallic non-current carrying items in a room or building as protection from electric shock. If a failure of electrical insulation occurs, all bonded metal objects in the room will have substantially the same electrical potential, so that an occupant of the room cannot touch two objects with significantly different potentials. Even if the connection to a distant earth ground is lost, the occupant will be protected from dangerous potential differences.
Bonding is particularly important for bathrooms, swimming pools and fountains. In pools and fountains, any metallic object (other than conductors of the power circuit) over a certain size must be bonded to assure that all conductors are equipotential and do not provide a hazardous conductive path.