FIELD: electrical power engineering. SUBSTANCE: facility is intended for preliminary surveys while designing and erecting grounding devices which are used by services of enterprises, including small businesses of various forms of ownership. Objective of invention lies in increased measurement accuracy in points with local surface inclusions with specific resistance different from specific resistance of ground. Proposed facility includes generator of stabilized electric current and microvoltmeter with voltage divider and circuit of replacement of measured signal with own signal, two potential electrodes M and N driven into ground and used to measure difference of electric potentials between points M and N on ground surface. One electrode is electrically connected to one terminal of microvoltmeter and another electrode is connected to second terminal of microvoltmeter. Current electrodes A and B are meant for transmission of current from generator of stabilized electric current through ground. One electrode ( current electrode A ) is located between potential electrodes M and N in section of straight line connecting mentioned potential electrodes M and N ( section MN ) and is electrically coupled to one pole of generator of stabilized electric current, second current electrode ( electrode B ) is electrically connected to second pole of generator of stabilized electric current. Connecting wires for above- mentioned electric connections include additional current electrode B0, driven into ground at vertex of isosceles triangle with base formed by section MN and height equal to ten sections MN and switch meant for temporary disconnection of electrode B from generator of stabilized electric current and for connection to it of additional current electrode B0 for tuning of facility for vertical electric sounding of ground by way of transmission of electric current from generator of stabilized electric current between electrodes A and B0 and installation of electrode A in section MN in such position in which difference of electric potentials induced by current electrode A in points M and N grows equal to zero. EFFECT: increased measurement accuracy. 1 dwg
