Stray currents are a kind of directional movement of charged particles that occurs in the earth when the latter is used as a conductor. The main danger of this phenomenon is the development of corrosion of those metal objects that are underground or at least partially in contact with it.
Stray currents occur when several metal parts (metals must necessarily be dissimilar), between which there is contact, are placed in some kind of electrolytic liquid. This liquid can be absolutely everything except distilled water. At the same time, as the temperature rises, the conductivity of the electrolyte will only increase, as, for example, happens with ships that move from the northern seas to tropical countries.
Stray currents can be caused by both internal and external sources, such as, for example, a short circuit in the electrical network, incorrect connection of elements, poor insulation of electrical wiring. As for the majorbuilding structures, which can be safely attributed to any multi-apartment residential building, then stray current is formed in them due to the fact that a potential difference forms between the grounding elements in different parts of the building.
As you know, any metal structure must be closed to the neutral conductor in the input-distribution device. Such a system is called a potential equalization system, it is necessary so that no directed electric current occurs between the grounding elements.
Also an important reason for the formation of stray currents and, as a result, electrochemical corrosion, is the widespread replacement of metal pipes in apartments with plastic ones. The thing is that in this case, the metal connection is broken between the main risers, which are grounded through the potential equalization system, and additional pipes that lead, for example, to a heated towel rail. In this case, a potential difference is formed between the riser and the auxiliary pipes, and if a conductor appears between them, for example, flowing water, then an electric current occurs.
Protection against stray currents is to equalize the potentials between metal structures. To do this, it is enough to connect the main riser and auxiliary pipes, after which the possibility for the appearance of electric current will disappear.
Another danger is that water moving through pipes, which, as mentioned above, is an excellent conductor,constantly in contact with the pipes themselves - dielectrics. From this friction, an electric current arises, which, in accordance with the basic physical laws, will accumulate at the ends of the metal structures. The resulting static charge will play an important role in the fact that the resulting stray currents will have greater strength. This needs to be considered.
Thus, stray currents are a fairly common phenomenon in everyday life. To avoid their unpleasant impact, it is necessary to carefully approach the grounding of all metal structures in the house, especially considering that some of the pipes are now being replaced with metal-plastic ones.
