Focusing on the grounding problem of the electrical safety, and considering the necessity of creating an electrical teaching power laboratory, we reveal the relation between the grounding resistance of the laboratory (the building) to the permitted power of the electrical generator to be studied in the laboratory. It is desirable to have a sufficiently powerful generator for study, but the safety requires a limit for the power. For the analysis, we introduce a single “parameter of order”, and, using it, create a simple theory of a rather complicated system, obtaining an important estimation and a conclusion, associated with the safety of the students intended to work in the laboratory.

power engineering, grounding (earthing), electrical engineering education.