Why Sometimes Tap Water Can Be Electrified? 0 8

In electrical engineering, the term “ground” refers to the potential that corresponds to the level of the ground beneath a building. All people and objects inside the building (except for the wiring) should have a ground potential to avoid electric shock.

However, potential is also present on the wires of the electrical network. One of the wires carries the phase — an alternating potential that powers devices; the other wire is neutral, representing a constant potential corresponding to the ground at the electrical substation. This potential may differ from the local ground level.

If the neutral in a device is (mistakenly) connected to the casing, and someone in the hallway grounds such a device through the plumbing, the potential of the pipe will differ from the ground. As a result, electric shock may occur from the pipe (and the water within it). This can also happen when someone tries to bypass the electric meter by using the ground from the plumbing pipe instead of the neutral.