Dangares of stray current to information and communication technologies in electrical installations with TN-C-S system of distribution

In electrical installations with TN-C-S system distribution with unsymmetrical or unfullphase load occurs return current, which is the point of connection of neutral (N), protective (PE) and protection-neutral (PEN) conductors industries. One part of this current over the protection-neutral (PEN) conductor returns to the substation, while the other part is distributed over protective (PE) conductors, conductors bonding (PA) and metal constructions in the building, and then through the earth back to the substation. The aim of this paper is to point out the dangers to information and communication technology by stray currents in their passing through various metal constructions in an object, such as: water pipes, gas pipes, heating pipes, steel reinforcement in concrete constructions building, lightning installation, metal casings of energy and information and communication cables etc.