We know that 1.5 volt batteries are safe, but outlets are too dangerous and should be covered to protect children. We also know not to use a hair dryer in the bath. But have you ever thought about how electricity hurts people? The leakage protector fails, and it cannot guarantee that the leakage is more than 30mA and the action trips. Because the ground wire in the home is not properly grounded. The metal casing of the electric water heater used has no grounding wire or is poorly grounded, and the steeper the slope, the more water wants to flow down. The zero voltage between two points is like a plane, so no current flows.